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NEET Biology Notes For Major Abiotic Factors

NEET Biology Notes For Temperature

Ecologically, it is the most relevant factor as temperature variation affects the enzyme kinetics, basal metabolic activities, and physiological functions of organisms. So, thermal tolerance de- cides to a large extent the geographical distribution of different species.

NEET Biology Notes For Stenothermal

Such organisms live in areas where the temperature is uniform throughout the year. These organisms cannot tolerate temperature variation.

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NEET Biology Notes For Eurythermal

Such organisms can tolerate large changes in temperature. These organisms are classified into four temperature groups on the basis of their occurrence in different climatic zones.

• Megatherms: High temperature throughout the year as found in a tropical zone.
• Mesotherms: They are adapted to winters and high summer temperatures. These organisms live in subtropical zone.
• Microtherms: They live in temperate areas where the winter temperature is low but the summer temperature is moderate.
• Hekistotherms: These organisms are adapted to a brief period of summer below 10°C and a long snowy winter period. This condition occurs in arctic or alpine zone.

Some effects of temperature are defined as under:

• Bergman’s rule: Warm-blooded animals (birds and mammals) have a larger body size in cold climate than in hotter areas..
• Allen’s rule: Extremities (legs, ears, tail, and mouth) of warm-blooded animals become smaller in colder areas as compared to the animals of warmer areas.
• Renton’s rule: In a colder climate, birds possess narrow and acuminate wings as compared to broader wings of birds found in warmer areas.
• Jordan’s rule: As the temperature is lowered, some fishes possess a larger size with a larger number of vertebrae.

NEET Biology Notes For Thermoperiodicity

Thermoperiodicity or thermoperiodism is the response of living organisms to regular changes of temperature. It is of two types: diurnal and seasonal.

• Diurnal thermoperiodicity: It is the response of organisms to daily changes of temperature. Generally, the day-time temperature is higher while the night-time temperature is lower.
• Seasonal thermoperiodicity: It is the response of organisms to seasonal changes in temperature. Along with photoperiodicity, it controls the growth of plants.

NEET Biology Notes For Thermal Stratification in Lakes

The occurrence of different temperatures in different horizontal layers as in a forest or a deep water body is called thermal stratification. A deep-water body, such as a lake, has three temperature strata: epilimnion, metalimnion, and hypolimnion.

• Epilimnion: It is the upper stratum in the water body. Epilimnion is warmer during summer and cooler during winter.
• Metalimnion: It is a short transitional zone between epilimnion and hypolimnion. The middle part of metalimnion is called thermocline. It is the area of maximum temperature changes.
• Hypolimnion: It is the lower stratum of a water body with lesser temperature fluctuations.

class 12 organisms and population notes

NEET Biology Notes For Water

Water is an important component of protoplasm, which is a general solvent. Water is also present over more than 71% surface of the earth as oceans, lakes, rivers, ice caps, and glaciers. The seawater has a high percentage of salt content (3.5%). Water present on land is called fresh water. Its salt content is low-less than 0.5%. The salt concentration (measured as salinity in parts per thousand) is less than 5% in inland water, 30-35% in the sea, and more than 100% in some hypersaline lagoons.

The regular movement of water among various regions and components of biosphere, viz., aquatic systems, air, and land, constitutes a water cycle. Water comes over land and water bodies as precipitation or rainfall. The total global rainfall is 4.46 G. Precipitation comes from water vapors present in the air. At any time, the atmosphere contains only 0.13 G of water vapors (1 G or genogram

Animals found in coastal water are called neritic and those found in open water are termed pelagic. Pelagic organisms are plankton (if microscopic), neuston (if macroscopic and found on the surface), and nekton (if actively swimming). Organisms found at the bottom of water bodies are called benthos.

NEET Biology Notes For Light

Light has a wide range of spectrum. The electromagnetic spectrum is a complete range of oscillating waves that travel together through space at a speed of 3 x 105 km/s. At 83 km above the surface of the earth, solar radiation carries an energy equivalent to 2 cal/cm2/min. This value is called solar constant.

Shortwave radiations are cosmic rays (with a wavelength less than 10-5 nm), gamma rays (103-105 nm), X-rays (10-1–10-2 nm), and UV rays (100-400 nm).

All shortwave radiation is extremely harmful. Most of them are trapped in the ionosphere and mesosphere. UV rays are also harmful.

UV-C and half of UV-B radiations are absorbed by the ozone layer of the stratosphere. A large amount of the rest is dissipated by the particles of troposphere; only a small amount reaches the earth.

Light affects photosynthesis, growth, reproduction, movement, stratification, photoperiodism, and phenology in plants, whereas it affects migration, reproduction, development, pigmentation, locomotion, and the period of activity in animals.

NEET Biology Notes For Light Zonation Of Lakes

• Littoral zone: It is exposed to wave action and is highly productive.

• Limnetic zone: It is an open water body.
• Euphotic zone: This zone receives maximum light above the light compensation point.
• Disphotic zone: This zone receives diffused light at or below the light compensation point. It is also known as the twilight zone.
• Profundal (dark, abyssal) zone: It has no light.
• Benthic zone: It lies at the bottom of the sea.

NEET Biology Notes For Soil

Soil Composition

Soil consists of four components: two solid and two nonsolid. The solid components are mineral particles and organic matter. The nonsolid components are air and water. A fifth component of variable nature is soil organisms.

Chief characteristics of soil are studied with the help of a soil profile. The type of soil profile depends upon the climate and vegetation of the area. The smallest three-dimensional volume of the soil required to study the profile is called pedon. Most soils possess three-four horizons and a number of subhorizons. A soil horizon is a horizontal layer approximately parallel to the soil surface that possesses distinctive properties which are unlike the ones present in adjoining regions. In general, a profile consists of O, A, B, C, and R horizons.

• Weathering: It is the breaking of rocks into fine particles as present on the soil. Weathering occurs by the following methods:
  • Physical weathering: It is caused by alternate heating and cooling, alternate wetting and drying, and action of frost, snow, rain, and wind.
  • Chemical weathering: Oxidation, reduction, carbonation, and solubilization are performed to break the rock.
  • Biological weathering: It is caused by lichens, mosses, and other organisms.
• Humification: It is addition of organic matter or humus to a weathered rock. Humification is essential to starting biological activity and nutritional cycling. Humus is a dark-colored amorphous substance. It is slightly acidic and colloidal and is a reservoir of nutrients. The main functions of humus are biogeochemical cycling, preventing soil from compaction, helping in the formation of soil crumbs, and improving the aeration and water-holding capacity of the soil. It also makes the soil spongy, therefore, rendering it easy for penetration by roots.
• Eluviation and illuviation: The two processes bring about transport and deposition of materials in the soil. Eluviation is washing down of materials from the upper strata of soil and helping in enriching the different layers of soil with minerals. Illuviation is deposition of minerals in the lower strata of soil.
• Mineral matter: It consists of inorganic substances present as particles of different sizes and composition.
  • Gravel: It is made of fine pebbles with a size of 2-10 mm.
  • Sand: It consists of grains of quartz or silicon dioxide (SiO2). Size varies from 0.02-2.0 mm. Sand is chemically inert. It allows quick percolation of rain or irrigation water. Aeration is good.
  • Silt: It is formed of fine grains of quartz. The size is 0.002-0.02 mm. It is chemically inert.
  • Clay: It is made of Al, Fe, and Si. The size is less than 0.002 mm. Clay particles are chemically active and have fine interspaces that can hold abundant water, but aeration is poor.
  • Soil air: It is the air present in macropores with a size between 20 and 50 μm. A good soil should have 25% air by volume. Soil air is required for the respiration of roots and several microorganisms. Soil air is richer in CO2 and poorer in O2.
  • Soil porosity: It is the percentage of interspaces present per unit dry weight of soil. The value of soil porosity is 30% in sandy soil, 45% in loam soil, and 50% in clay soil. There are two types of soil pores: micropores and macropores. Micropores are small sized interspaces having a diameter of 20 μm or less. These hold water by capillarity. Macropores are interspaces with a size of more than 20 μm.
    Residual soils develop in situ. Transported soils are brought from other places through gravity (colluvial), running water (deposited on flood plains and called alluvial), wind (colian or acolian), and glacier (glacial soil).

Soil Types:

• Red soils: These are acidic laterite soils which are deficient in lime, magnesium, phosphorus, and potassium but rich in organic matter, iron, and aluminum. These soils support tea, coffee, rubber, cardamom, areca nut, and paddy plantation.
• Black soils: Also called black cotton soils, locally known as regular, these soils have dark brown or black color from organic matter, clay/hydrated iron, aluminum silicate, and undifferentiated B-horizon (A-C soil).
• Terai/Bhabar soils: These soils are mostly colluvial and highly productive.

Soil Texture:

There are three main types of soil textures.

• Sandy soils: These soils contain about 80% or more of sand, the remaining being silt and clay. Sandy soils are porous and loose. Their water-holding capacity is poor and there is little chemical nutrition.
• Clay soils: These are soils having 40-50% clay, the rest being silt. Sand is little. Clay soils have abundant capillary pores; therefore, their water-holding capacity is high. Inorganic nutrients are available in good quantity. However, aeration is poor.
• Loam soils: These soils contain 20% clay, 40% sand, and 40% silt. These have good mineral nutrition, aeration, and hydration. Therefore, loam soils are the best for plant growth.

Soil pH:

Soil pH determines the type of soil microorganisms, the solubility of different minerals, and the type of plants which will grow on it. In alkaline soils (pH above 7), there is reduced availability of Zn, Mn, Cu, and Fe. In acidic soils, there is an abundance of Fe, Mn, and Al but deficiency of Ca, Mg, and K. Certain soils possess excess of salts, especially of Na and Mg. These are called saline soils. Salinity increases with excessive irrigation. Another category of infertile soil is alkali soil.

NEET Biology Notes For Topography

Topography, i.e., surface configuration of an area (physical features like hills, plains, or slopes), also influences the distribution of organisms. For example, the center and edge of a pond or a stream, the top side and underside of a rock, and the north and south face of a ridge or a mountain are usually inhabited by different species of organisms,

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NEET Biology Notes For Fungi Zygomycetes

• Common Name: Conjugation fungi.
• Cell Wall: Chitinous
• Mycelium: Coenocytic
• Sexual Reproduction: Gametangial copulation
• Sexual Spore: Zygospore Motile stage is absent.

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NEET Biology Notes For Life Cycle Of Rhizopus

Rhizopus grows on carbohydrate-rich medium. It is a saprophyte with an absorptive mode of nutrition.

The mycelium contains two types of vegetative hyphae, which arise from definite points called apparent nodes or holdfasts. The two types of hyphae are stoloniferous and rhizoidal in the asexual phase the mycelium produces a third type of hyphae called sporangiophore.

A dome-shaped partition or columella separates the spore-bearing part from the rest of the sporangiophore. During sexual reproduction, a fourth type of hyphae arises. They are called as zygospores.

1. Life Cycle Of Rhizopus Asexual Reproduction: Mycelium can multiply asexually by means of three types of mitospores: sporangiospores, chlamydospores, and oidia. Oidia formation occurs when the hyphae get submerged in sugary fermentation. Chlamydospores are produced under unfavorable conditions while sporangiospores are formed in favorable environments.
2. Life Cycle Of Rhizopus Sexual Reproduction: Most of the species of Rhizopus are heterothallic, but a few (for example, R. sexualis) are homothallic. The phenomenon of heterothallism was discovered by Blakeslee in R. stolonifer. Heterothallism results in greater variations and it is a device to prevent inbreeding.

Sexual Reproduction occurs by conjugation. In heterothallic species, mycelia are morphologically similar but genetically different. They are designated as plus (+) and minus (-). The presence of both types of mycelia stimulates (through trisporic acid) each other to produce special subaerial hyphae called zy- gophores.

The two types of zygophores come in contact and produce gametangia at the tips of club-shaped branches. The common wall between the gametangia dissolves. Their protoplasts function as gametes. They fuse to form a diploid zygote- spore. The wall of the mature zygospore is five-layered (two in exosporium and three in endosporium).

NEET Biology Notes For Zygomycetes

Zygospore germinates under favorable conditions. Its diploid nuclei divide meiotically to produce haploid nuclei. Only one haploid nucleus remains functional. It multiplies repeatedly to produce multinucleate conditions.

Importance Of Zygomycetes:

• Ramysin antibiotic is produced by Mucor Armenians.
• The growth of Mucor arrhizus removes heavy metal contamination of water.
• Fumaric acid is obtained from R. stolonifer and citric acid is obtained from Mucor.
• Rhizopus species produces soft rot or leak disease in sweet potatoes, apple, and strawberries.
• Ahsidia corymhifera causes bronchomycosis.

NEET Biology Notes For Ascomycetes (Sac Fungi)

• Plant body is unicellular (for example, yeast) or mycelial (for example, Penicillium, Aspergillus).
• Mycelium is branched, septate, generally monokaryotic (for example, Penicillium) or dikaryotic (shorter phase).
• The simple septal pore is present in mycelia, which may get partially plugged by membrane-bound bodies and a crystalline structure called worn bodies.
• Asexual reproduction takes place by the formation of conidia.
• Sexual reproduction occurs by (1) gametangial contact (for example, Pyronemd), (2) conjugation (for example, yeast),
• somatization (for example, Ascoholus), (4) homogamy (for example, Peziza), or (5) autogamy.
• Each ascus lias four to eight ascospores arranged either in linear order (for example, Neurospora) or unorderly (for example, yeast).
• Asci are aggregated into fructifications called ascocarps. It is surrounded by a peridium of vegetative hyphae and internal contents collectively called centrum.

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NEET Biology Notes For Kingdom Fungi

These are eukaryotic, heterotrophic, non-flowering, thalloid, mostly multicellular, decomposers, mineralizers of organic wastes, and help in the recycling of matter in the biosphere. The study of fungi is called mycology’. The term fungus was given by Gaspard Bauhin. Some important mycologists and their contributions/popularly known as

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Pier Antonio Micheli: Father or founder of mycology

E.M. Fries: Father of systematic mycology

H.A de Barry: Father of modem mycology

E.J. Butler: Father of Indian mycology

K.C. Menta: Famous for studying rust disease in wheat

Bessey: Defined fungi as chlorophyll-less. nonvascular Plants

NEET Biology Notes For Fungi General Characters

Fungi are mostly terrestrial and occur in soil. They may be aquatic, parasitic, saprotrophic, or symbiont (Lichen and Myconhiza). Saprophytic fungi are called vegetable vultures.

On the basis of habitat, fungi are classified as coprophilous (on dung), corticolous (on bark), epixylic (on wood), xerophilous (on burnt wood), lignicolous (on lignified wood), keratinophilic (on hairs, horns).

NEET Biology Notes For Fungi Somatic Structure

In most of fungi, the thallus consists of a mass of fine, tubular branching thread-like structures called hyphae which are usually woven into a network called mycelium.

Mycelium Is Of The Following Types:

1. Primary Mycelium: Uninucleate, septate, for example, ascomycetes.
2. Secondary Mycelium: Dikaryotic mycelium, for example, basidiomycetes.
3. Coenocytic Mycelium: Multinucleate, aseptate, for example, oomycetes, zygomycetes.

NEET Biology Notes For Modifications Of Mycelium

• Prosenchyma: Loosely arranged long elongated hyphae.
• Pseudoparenchyma: Densely arranged hyphae giving a false appearance of parenchyma.
• Sclerotium: Tough and hard perennating structure formed by a compact mass of hyphae, for example, Claviceps.
• Rhizomorph: Dense mass of hyphae, running parallel. The hyphae lose their individuality; and subterranean nature; the growing tip looks like a root, for example, Agaricus.
• Appressorium: Terminal swollen structure of germ tube for penetration and attachment.
• Haustoria: Terminal swollen structure of germ tube for absorption of food.
• Snares Or Hyphal Traps: Helps in capturing nematodes in preda¬ceous fungi such as Dactylaria and Arthrobotrys.

NEET Biology Notes For Fungi Cellular Structure

• The cell wall is made of fungus cellulose/chitin, a polymer of TV-acetyl glucosamine (except oomycetes where cellulose occurs).
• Presence of unicistemal Golgi bodies.
• Karyochorisis type of mitosis occurs, it is mitosis with intranuclear spindle fibers formation.
• Reserve food material is glycogen and oil.
• Hyphae can be septate or aseptate. There are three types of septa in septate hyphae:
  • Complete septum,
  • Septum with simple pore (ascomycetes), and
  • Dolipore septum (basidiomycetes).

Fungi Nutrition: It is heterotrophic and absorptive.

NEET Biology Notes For Fungi Asexual Reproduction

Fungi Asexual Reproduction occurs by following asexual spores.

1. Zoospore: Many fungi, especially aquatic fungi, produce this type of spore. It may be uniflagellate or biflagellate. The flagella are always heterokont type, i.e., of unequal length. Example. Saprolcgnia.
2. Conidiosporcs Or Conidia: These are single-celled, double-celled, or many-celled structures borne on the sides of the hyphal structures called conidiophores. These are borne singly in chains.
3. Chlamydospores: These are usually formed during unfavorable conditions and are thick-walled, single-celled spores that are highly resistant to adverse conditions, for example, Mucor.
4. Sporangiospore: Noil-motile, multinucleate spore produced inside the sporangium, for example. Rhizopus.
5. Oidia: Non-motile, thin-walled spores develop under the condition of excess sugar. The budding condition of oidia is called the tomla stage, for example, Mucor, and Rhizopus.

Fungi Sexual Reproduction: It involves plasmogamy, karyogamy, and meiosis. As a result of sexual reproduction, sexual spores are produced. However, these are fewer in number than the asexual spores. There are several types of sexual spores:

• Ascospores: Usually, but not always, single-celled haploid spores are produced in a sac called an ascus (plural asci).
• Basidiospores: Haploid spores produced exogenously by special structures called basidia (singular basidium)
• Zygospores: Thick-walled diploid spores produced by tire fusion of entire gametangia.
• Oospores: Formed within a special female structure, the oogonium as a result of fertilization of female oospheres by male gametes.

Plasmogamy is brought about by any one of the following methods:

• Gametic Fusion Or Copulation: It may be isogamy, anisogamy, or oogamy, for example, Phytophthora.
• Gametangial Contact: Fusion of female and amoeboid male gamete by fertilization tube, for example. Albugo, Pythium.
• Gametangial Copulation: By fusion of gametangia, for example, Rhizopus, and Mucor.
• Spermatization: Fusion between spennatia and receptive hyphae, for example, Puccinia.
• Somatogamy: Fusion of somatic cells, for example, Agaricus.
  • The site of meiosis is zygospore/zygote/oospore, for example, oomycetes, or zygomycetes.
  • Site of meiosis is ascus, for example. ascomycetes.
  • Basidium, for example, basidiomycetes.

NEET Biology Notes For Classification Of Fungi

Humycota (true fungi) are classified into five classes:

1. Oomycetes/Phycomycetes
2. Zygomycetes
3. Ascomycetes
4. Basidiomycctcs
5. Deutcromycetes

NEET Biology Notes For Fungi Oomycetes/Phycomycetes

• Common Name: Algal fungi
• Mycelium: Coenocylic
• Cell Wall: Cellulosic
• Asexual Spores: Zoosporcs/conidiosporangia
• Sexual Reproduction: Gametic fusion and gametangial contact
• Sexual Spore: Oospore
• Aquatic phycomycetes are called water molds, for example, Saprolegnia, Plasmodiophora, etc.
• Saprolegnia grows on dead bodies of insects, houseflies, tadpoles, and gills of fish causing salmon disease of gills in fishes. It shows diamagnetism, i.e., the formation of two types of zoospores-primary and secondary zoospores.

Common examples of oomycetes and diseases caused by them are as follows:

• Synchytrium Endobioticum: Black wart disease of potato.
• Phytophthora Infestens: Late blight disease of potato. The great Irish famine (1845-47) was caused by this fungus.
• Albugo Candida: White rust of crucifers.
• Pythium Debaiyanum: Damping off disease (seedlings).
• Sclerospora Graminicola: Downy mildew of cereals

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NEET Biology Notes For Kingdom Protista

They are solitary, unicellular eukaryotic organisms. Few may be colonial.

• They are mostly aquatic organisms.
• A well-defined nucleus is present. Protists can be uni-nucleate, binucleate, or multinucleate.
• The cytoplasm contains, besides ribosomes, a variety of membrane-bound organelles. Many have centrioles also.
• Cell wall, if present, contains cellulose.
• Locomotion can occur through flagella, cilia, and pseudopodia. Ciliary mode is the fastest averaging to 2 mm/s.
• Flagella and cilia, when present, have 9 + 2 patterns of microtubular strands.
• The nutritive modes are variable: photosynthetic (holophytic), ingestive (holozoic, phagotrophic), and absorptive (saprobic, parasitic). The photosynthetic protists act as chief producers of food in the oceans and in freshwater.
• Some protistans are parasitic. Some live symbiotically as in the guts of other animals while a few act as decomposers.
• Reproduction is through asexual and sexual processes. Sexual reproduction involves meiosis and syngamy. Meiosis is zygotic in some and gametic in others.
• Reserve food can be starch, paramylum, chrysolaminarin, glycogen, and fat.

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NEET Biology Notes For Photosynthetic Protists: Diatoms (Chrysophytes)

Salient Features Of Diatoms

• Basically unicellular and aflagellate except in the reproductive state.
• They possess beautiful colors and shapes.
• They may be marine, freshwater forms, or ones dwelling in moist terrestrial habitats.
• A transparent, siliceous, bivalved frustule covers the body. It has two valves, the upper epitheca and the lower hypotheca. The frustule is variously sculptured. It may possess bilateral symmetry (centric as in Melosira) or radial symmetry (centric as in Melosira).
• Large central sap vacuole present. Primordial utricle condition exists.
• Nutrition: holophytic or photosynthetic. Plastids contain chlorophyll-a and chlorophyll-c, carotene, and a variety of xanthophylls (diatoxanthin, etc.). The reserve food is oils and leucosin. Proteinaceous volutin granules are also present.
• Movement is brought about by mucilage propulsion.
• Diatoms synthesize about half the total organic matter synthesized in the biosphere. Oils extracted from fish are actually contributed by diatoms.
• Siliceous frustules of diatoms form diatomaceous earth diatomite or kieselguhr which is employed for a variety of purposes such as filtration, soundproofing, industrial catalysts, etc.
• They serve as sewage pollution indicators.

NEET Biology Notes For Reproduction In Diatoms

1. Asexual Reproduction: By binary fission, each daughter cell receives the epitheca from the parent cell because of which the size goes on reducing in successive generations. Extrusion of protoplasm may serve to restore normal cell size. Resting spores called statospores may be formed by centric diatoms.
2. Sexual Reproduction: It ranges from isogamy to oogamy. The zygote grows in size and forms a rejuvenescent cell called an auxospore.
3. The life cycle is diploidic.

botany notes

NEET Biology Notes For Dinoflagellates – Salient Features Of Dinoflagellates

• These are basically unicellular (rarely palmelloid or filamentous), and biflagellate (rarely nonmotile) with heterokont conditions.
• They are mostly marine; some are freshwater species also.
• Cells are generally covered by a rigid coat (theca/lorica) of sculptured plates of cellulose and pectin Due to the presence of sculptured plates these are also called armored dinoflagellates.
• It is absent and replaced by pellicle/penpals in endosymbiotic dinoflagellates called zooxanthellae
• The longitudinal flagellum is narrow and smooth and lies in the longitudinal groove (sulcus).

The transverse flagellum is ribbon-like and lies in the transverse groove (cingulum/annulus/girdle):

• Both flagella are oriented at right angles to each other and produce spinning movement.
• Therefore, these protists are also called “Whirling whips ”
• Holophytic or photosynthetic (rarely holozoic).
• Pigments are chlorophyll-a, c, carotene, and xanthophylls (such as peridinin).
• A non-contractile vacuole, called a pustule, is present.
• Reserve food: carbohydrates and oil.
• Gymnodinium and Gonyanlax cause red tides.
• Gonyaulax calendula produces saxitoxin (a neurotoxin) that accumulates in marine shellfish. When these shellfish are eaten by humans, it causes paralytic shellfish poisoning (PSP) that may be fatal.
• Bioluminescent dinoflagellates: Noctiluca, Pyrodinium, Pyrocystis.
• Some dinoflagellates possess trichocysts and cnidoblasts (nematocysts).
• The nucleus in dinoflagellates is called a mesokaryon (Dodge et. al). It is large and possesses permanently condensed chromosomes that lack association with histones.
• The life cycle is haplontic (for example, Ceratium) or diplontic (for example, Noctiluca)

NEET Biology Notes For Reproduction In Diatoms

1. Diatoms Asexual Reproduction: Through cell division and encystment.
2. Diatoms Sexual Reproduction: It is reported in some organisms such as Ceratium. It may be isogamotts or anisogamous.

NEET Biology Notes For Kingdom Monera

Kingdom Monera is the kingdom of prokaryotes that includes Eubacteria, Archaebacteria, Actinomycetes, Mycoplasma, Spirochaetes, Rickettsiae, Chlamydiae, Cyanobacteria, etc.

• These are unicellular/colonial/multicellular prokaryotic organisms without nuclear membrane, nucleolus, chromatin, and histone proteins.
• The nucleoid or genophore incipient nucleus or pro-chromosome is composed of naked DNA, RNA, and non-histone proteins.
• Membrane-bound organelles are absent.
• Cyclosis is absent and ribosomes are of 70S type.
• The cell wall is made of peptidoglycan (exceptions are archaebacteria and mycoplasmas).
• Respiratory enzymes are found associated with the plasma membrane.
• Reproduction is by the asexual method.
• Cell division is the amitotic type and lacks spindle formation.

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NEET Biology Notes For Archaebacteria

They form a primitive group of bacteria and are the oldest of the “living fossils.” Some important characteristics of archaebacteria are distinct from eubacteria and are as follows:

• The cell wall lacks muramic acid and peptidoglycan.
• The lipids contain phytanyl side groups (branched lipids). Branched-chain lipids decrease membrane fluidity and increase tolerance to extremes of heat as well as low pH.
• Ribosomal proteins are unusually acidic.

Archaebacteria Are Of The Following Types

• Methanogens: Methanobacteria are obligate anaerobic forms of Gram-negative bacteria that produce methane gas from CO₂  or formic acid. These bacteria are found in the rumen (first part of the stomach) of cattle and in marshy areas.
• In biogas plants, they produce methane gas. The cell wall contains protein (for example, Methanospirilium, Metlumococcus) or noncellulosic polysaccharides (for example, Methanosarcina) or pseudoinurein (for example, Methanobacterium) in which Ar-acetyltalosaminuronic acid is present instead of NAM.
• Halophiles: Halophilic bacteria are Gram-negative obligate anaerobic forms associated with coccoid forms of bacteria. Their habitats are tidal pools, salt ponds, brines, salted fish, salted hides, etc. Halobacteria can grow well in culture medium containing as high as 25-35% of NaCl. In the presence of sunlight, they develop a purple pigment (bacteriorhodopsin) in the membrane to use sunlight. They trap light with the help of purple pigment and synthesize ATP, but do not use the latter for synthesizing organic food.
• Thermoacidophiles: They are aerobic from of Gram-negative bacteria found in hot sulfur springs. At a temperature of about 80°C, they oxidize sulfur to sulfuric acid. This happens in a highly acidic medium (pH = 2). Under anaerobic conditions, they reduce sulfur to hydrogen sulfide, and under aerobic conditions, they oxidize sulfur to sulfur dioxide. They are facultative anaerobes and are chemosynthetic in nature, for example, Thermoplasma and Thermoproteus.

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NEET Biology Notes For Virus

General Structure Of Virus A Virus Has Following Parts:

• Envelope: It has smaller subunits, known as telomeres. For example, herpes virus, HIV, etc.
• Capsid: Protein coat made up of subunits called capsomeres.
• Nucleoid: Viruses contain either DNA or RNA.

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On the basis of the type of genetic material, viruses are classified as:

1. Deoxy Viruses:
   • Contain double-stranded DNA (ds DNA), for example, pox virus, and cauliflower mosaic virus.
   • Contain single-stranded DNA (ss DNA), for example, x 174.
2. Riboviruses:
   • Contain ds RNA, for example, reovirus, wound tumor virus.
   • Contain ss RNA, for example, TMV, HIV, and influenza vims.

NEET Biology Notes For Structure Of Some Viruses

1. Tobacco mosaic virus (TMV) is elongated rod-like, 300 (one, ISO in diameter with a molecular weight, of 39.4 x 106. 2130 capsomercs are arranged helically to form the capsid. 40 capsid tires present in three turns and 130 turns in complete virus capsid. UNA strand is helical ssRNA and consists of 6400 nucleotides. Thus, the ratio of nucleotides and capsomeres =3:1.
2. Pox virus/variola is the causal agent of smallpox. These are among the largest of animal viruses and are rectangular (brick-shaped), 300 x 230 nm in size. The genome is dumbbell-shaped with a central core of dsDNA. The core has two enzymes: RNA polymerase and ATP phosphohydrolase.
3. AIDS virus consists of ssRNA. It has two copies of ssRNA. The outer cover has five-layer, the outermost glycoprotein, followed by a double lipid layer, and the innermost has two protein layers
4. T₄ bacteriophage has a tadpole-like structure with a polyhedral head connected to a helical tail. J lic head consists of nucleic acid surrounded by a protein coat or capsid. Nucleic acid is double-stranded f)NA. The tail is proteinaceous tube-like, core surrounded by a sheath. At one end, lube is jointed to the head by a thin collar. At the other end, it has a hexagonal base plate with six small tail pins and six tail fibers which help in the attachment of the phage to the host cell.

Reproduction In Virus: Reproduction is of two main types: phagic and pinocytic.

1. Phagic Reproduction: It is further of two types:
   • Lytic Cycle: Occurs in virulent phages, for example, T4 bacteriophages.
   • Lysogenic Cycle: Occurs in temperate viruses such as phage.
2. Pinocytic Reproduction: An example, occurs in TMV.

Diseases Caused by Virus in Man

1. Cryptogram of Virus

The International Committee of Virus Nomenclature has developed a system for naming viruses. The system consists of two parts: the common name and the coded information about the virus. This is called a cryptogram.

1. Cryptogram Of TMV: R/1: 2/5: E/E: S/A
2. Cryptogram Of Pox Virus: D/2, 160/5-7.5,X/*,V/0
3. Cryptogram Of Poliovirus: R/1, 2.5/30, S/S, V/O
4. Cryptogram Of T4 Bacteriophage: D/2, 130/40, X/X, B/O

In a cryptogram,

1. The first pair represents the type of nucleic acid/number of strands in nucleic acid.
2. The second pair represents the molecular weight of nucleic acid/amount of nucleic acid expressed as a percentage.
3. The third pair denotes the shape of the virus/shape of nucleoprotein.
4. The fourth pair denotes the type of host/carrier used in the transmission of the virus.

2. Viroids And Prions:

Viroids were discovered by T.O. Diener. It has RNA without a protein coat. Viroids cause potato spindle tuber disease (PSTD), Chrysanthemum stunt, citrus exocortis, cucumber pale fruit, etc.

Prions are proteinaceous infectious particles. It causes:

1. Kuru (laughing death) disease
2. Mad cow disease (C-Jakob)
3. Alzheimer’s disease in human beings
4. Scrapie disease in sheep

NEET Biology Notes PDF Free Download

NEET Biology Notes For Penicillium

• Facultative parasite and saprophytic fungi.
• Mycelium is branched septate with simple septal pores and each cell is uni or multinucleate depending upon the species.
• Asexual Reproduction: By conidia. Conidiophores are often branched. The ultimate branches or metulae of conidiophore possess bottle-shaped sterigmata. Each sterigmata produces a chain of conidia. The conidia in the chain are arranged in basipetal order. Each conidium is uninucleate, non-motile, two-layered, dispersed by air, and germinates to form new mycelium.
• Sexual Reproduction: It produces dikaryophase and ascocarp. The ascocarp is a cleistothecium type. Each ascus has eight ascospores. Ascospore germinates to form new mycelium.

Read and Learn More NEET Biology Notes

NEET Biology Notes For Importance Of Penicillium

• Penicillin (the wonder drug, the first antibiotic): Flemming discovered penicillin from Penicillium notation. Nowadays, it is obtained commercially from P. chrysogenum.
• Griseofulvin and brefeldin are obtained from P. griseofulvin and P. brefeldin, respectively.
• Ripening of Camembert and Roquefort types of cheese is carried out by P. camemberti and P. roqueforti, respectively.

Some More Ascomycetes And Their Importance

• Aspergillus flavus: It produces a carcinogenic toxic called aflatoxin.
• A. oryzae: Source of diastase enzyme
• Claviceps Purpurea: Ergot of rye disease. Source of LSD (lysergic acid diethylamide)
• Erysiplte Graminicola: Powdery mildew of cereals.
• Morchella (morel): Ascocarp is edible, for example, Morchella esculent.
• Tuber (truffle): Ascocarp is edible, for example, Tuber aestivum.

NEET Biology Notes For Basidiomycetes (Club Fungi)

• They are decomposers of wood. They decompose cellulose and lignin. These are the most commonly seen fungi.
• Primary mycelium is monokaryotic (n) and short-lived. Secondary mycelium is bikaryotic (n + n) and long-lived.
• Septa bear dolipore except for rusts and smuts.

Clamp connections are present. They are meant for proper distribution of dikaryon at the time of cell division.

Basidiospores are four in number and are produced exogenously at the tip of sterigmata. In Agaricus bisporus, only two basidiospores are formed from each basidium.

NEET Biology Notes For Life Cycle Of Mushroom

• Agaricus (Psqffiota) campestris is the common field mushroom that has edible basidiocarp. The fungus is saprotrophic.
• The vegetative or assimilative part of mycelium is subterranean. It is found in moist humus-rich soil of open fields, grasslands, and piles of straw. The mycelium multiplies by fragmentation. Occasionally, oidia and chlamydospores are also formed.
• Mushrooms contain two types of mycelia, primary and secondary. Primary mycelium is short-lived. It consists of septate hyphae having monokaryotic cells or cells with a single nucleus. Sex organs do not differentiate.
• The mycelia are heterothallic, that is, there are two mating types, (+) and H. The hyphae of two matting types come in contact and show somatogamy or fusion between their cells. However, only plasmogamy occurs at this time. It gives rise to a dikaryotic cell that grows, divides, and produces a long-lived and extensive dikary¬otic or secondary mycelium.
• The hyphae of secondary mycelium show clamp connections and dolipore septa. Its cells possess two haploid nuclei (n + n) instead of the single diploid nucleus (2n) in diplophase or a single haploid nucleus (n) in haplophase.
• Under favorable conditions, hyphae of secondary mycelium collect at places and give rise to rounded or pyriform compact masses of hyphae called buttons. The buttons enlarge and produce aerial basidiocarps.

The basidiocarps of Agaricus are cream-colored to pinkish brown. In contrast, the secondary mycelium, from which mushrooms develop, is known as spawn. The basidiocarps or mushrooms often lie in rings. The latter are spoken as fairy rings.

• Each basidiocarp or mushroom consists of two parts, stipe and pileus. The stipe or stalk is fleshy. It is slightly swollen at the base. The pileus is an umbrella-like cap of the mushroom. In the button stage, the pileus is connected to the stipe, by a membrane called a veil or velum. It ruptures during the growth of pileus.
• However, its remains can be seen on the upper part of the stipe as the annulus. The pileus is circular in outline. The upper surface is more or less convex. The undersurface is flat or concave. It bears 300-600 radiating rows of vertical plates named gills (lamellae).
• The two sides of the vertically placed basidiocarp are lined by thousands of club-shaped basidia along with sterile paraphyses (singular paraphysis). The two together constitute the fertile layer or hymenium of the gill.

Hymenium is subtended by compact subhymenium. The center consists of interwoven hyphae. It is called trauma. Each basidium functions as the site for both karyogamy and meiosis.

• The two nuclei fuse to form a short-lived diploid synkaryon. The latter then divides meiotically giving rise to four haploid nuclei, two of (+) strain and two of (-) strain.
• The free end of the basidium now develops four peg-like outgrowths called sterigmata. Each sterigma forms an ovoid pinkish-purple meiospore at its tip, the same is termed as basidiospore
• A droplet is collected at the base of each basidiospore which creates tension for breaking and throwing the same. The air current carries away the discharged basidiospores. Basidiospores are of two strains, (+) and (-). After falling on a suitable substratum, each basidiospore germinates to produce monokaryotic primary mycelium.
• The fruiting bodies (basidiocarps) of Agaricus arise in concentric rings (called fairy rings/final flowers) from the mycelium present in the soil. Since the ring of underground mycelium spreads centrifugally, the diameter of the fairy ring also increases every year.

NEET Class 12 Biology Multiple Choice Questions – Environmental Issues

Question 1. Carbon monoxide is a major pollutant of 

1. Water
2. Air
3. Noise
4. Soil

Answer: 2. Air

Carbon monoxide (CO) is major pollutant in air, exhausted by various automobiles.

Question 2. Air pollution is caused by excess of 

1. Dinitrogen
2. Hydrogen
3. Water vapour
4. None of these

Answer: 1. Dinitrogen

Nitrogen form various oxides such as N₂O, NO, NO N₂O₅, and N₂O₅ play an important role in the formation of photochemical smog and acid rains. Thus, excess of dinitrogen cause air pollution.

” environmental issues mcqs”

Question 3. Statements given below are pertaining to air pollutants.

1. They cause injury to all living organisms.
2. They reduce the growth and yield of crops and cause premature death of plants.
3. They affect the respiratory system of humans and animals.

Choose the option containing the correct statements.

1. 1 and 2
2. 1 and 3
3. 2 and 3
4. 1, 2 and 3

Answer: 4. 1,2 and 3

• All the given statements are correct as Air pollution has several effects on all living organisms and on climate. Diseases like bronchitis, lung cancer and emphysema are caused by air pollution.
• NO₂ causes bronchitis and lowers the resistance to influenza.
• SO₂ obstructs breathing and irritates the eyes.
• Nitric acid, nitrous acid and sulphuric acid cause respiratory diseases. Air pollutants reduce the growth and yield of crops and cause premature death of plants.

Biology MCQs with answers for NEET

Question 4. The Air Prevention and Control of Pollution Act came into force in the year …A… It was amended in …B… to incorporate …C… as an air pollutant.

1. A–1980, B–1986, C–water
2. A–1981, B–1987, C–noise
3. A–1982, B–1988, C–radioactive
4. A–1983, B–1989, C–soil

Answer: 2. A–1981, B–1987, C–noise

Question 5. Which of the following is a primary pollutant?

1. CO
2. HNO₃
3. H₂SO₄
4. O₃

Answer: 1. CO

A primary pollutant is that which persists in the form in which it is released in the environment, e.g. CO.

Question 6. Assertion Secondary air pollutants are formed by interaction among the primary pollutants and are more toxic. Reason (R) DDT is a secondary air pollutant.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. Both A and R are false

Answer: 3. A is true, but R is false

A is true, but R is false because Secondary air pollutants are produced photochemically from primary pollutants. Smog, photochemical smog, ozone and PAN all are secondary air pollutants. DDT is a primary soil pollutant.

Question 7. Which of the following is a secondary pollutant?

1. CO
2. O₃
3. SO₂
4. CO₂

Answer: 2. O₃

O₃ (ozone) is a secondary pollutant. These are formed by the reaction of primary pollutants. CO is a quantitative pollutant. CO₂ and SO₂ are primary pollutants.

“global warming can significantly be controlled by “

Biology MCQs with answers for NEET

Question 8. One of the following acts as a secondary pollutant.

1. Br₂
2. CI₂
3. NO₂
4. HNO₂

Answer: 3. NO₂

Secondary pollutants are not emitted directly in the air, water or soil, but are synthesised by chemical reactions and the best examples are oxides of nitrogen. They further form ozone, PAN and aldehydes.

Question 9. The secondary pollutant which stops Hill reaction is 

1. Sulphuric Acid
2. Nitric Acid
3. Peroxyacetyl Nitrate (Pan)
4. Aldehydes
5. None of the above

Answer: 3. Peroxyacetyl Nitrate (Pan)

PAN prevents the photolysis of water in photosynthesis or Hill reaction.

Question 10. Match the following columns.

Answer:

1–1, 2, 4

2–3, 5

Question 11. Match the following columns.

Answer:

1–3, 4, 5, 6, 7

2–1, 2, 8, 9

Question 12. Consider the following statements about pollution.

1. Pollution is defined as an undesirable change in physical, chemical or biological characteristics of air, land, water or soil.
2. The Air (Prevention and Control of Pollution) Act was amended in 1987.
3. The Environment Protection Act, of 1976 was formed to bring into effect the parameters of the United Nations Conference on the Human Environment.

Biology MCQs with answers for NEET

Choose the option containing the correct statements.

1. 1 and 2
2. 1 and 3
3. 2 and 3
4. 1, 2 and 3

Answer: 1. 1 and 2

Statements 1 and 2 are correct, but 3 is incorrect because In order to control environmental pollution, the government of India has passed the Environment Protection Act, 1986 to protect and improve the quality of our environment (air, water and soil). The air act was amended in 1987 to include noise as air pollution.

Question 13. Which of the following is a weightless pollutant?

1. Sewage and exhaust emissions
2. SO₂ and NO₂
3. Photochemical smog
4. Heat, sound and radioactive wastes

Answer: 4. Heat, sound and radioactive wastes

Heat, sound and radioactive wastes are weightless pollutants.

“environmental questions “

Question 14. A scrubber in the exhaust of a chemical industrial plant removes CBSE AIPMT, Karnataka CET

1. Gases Like Sulphur Dioxide
2. Particulate Matter Of The Size 5 Micrometer Or Above
3. Gases Like Ozone And Methane
4. Particular matter of the size 2.5 micrometre or less

Answer: 1. Gases Like Sulphur Dioxide

A scrubber can remove gases like sulphur dioxide. In a scrubber, the exhaust is passed through a spray of water or lime

Question 15. In the scrubber, the exhaust is passed through a

1. Spray Of Water
2. Spray Of Lime
3. Both 1 And 2
4. Spray Of Electrons

Answer: 3. Both 1 And 2

A scrubber can remove gases like sulphur dioxide. In a scrubber, the exhaust is passed through a spray of water or lime

Biology MCQs with answers for NEET

Question 16. Consider the following statements about scrubbers.

1. It removes gases like sulphur dioxide from industrial exhaust.
2. The exhaust passes through a spray of water or lime.
3. Sulphur dioxide reacts with lime to form a precipitate of calcium sulphate and water dissolves gases.

Choose the option containing the correct statements.

1. 1 and 2
2. 1 and 3
3. 2 and 3
4. 1, 2 and 3

Answer: 4. 1,2 and 3

All the given statements are correct for the scrubber. A scrubber can remove gases like sulphur dioxide. In a wet scrubber, a fine spray of water or alkaline fluid like lime is allowed to fall over exhaust emissions. The particles also become heavy and fall down. The lime reacts with sulphur dioxide to produce a precipitate of calcium sulphate or calcium sulphide. Water is used to remove soluble gases and particles.

Question 17. The below diagram shows a scrubber. Identify A, B, C and D.

1. A–Particulate matter, B–Clean air, C–Dirty air, D–A dust particle
2. A–Dirty air, B–Clean air, C–Water lime spray, D–Slurry outlet
3. A–Slurry outlet, B–Dirty air, C–Particulate matter, D–Clean air
4. A–Dust particle, B–Clean air, C–Particulate matter, D–Water spray

Answer: 2. A– Dirty air, B–Clean air, C–Water spray, D–Slurry outlet.

Question 18. Cyclone collectors are nowadays commonly used to control 

1. Air Pollution With Special Reference To Dust Particles
2. Radioactive Pollution
3. Water Pollution In General
4. Water pollution with special reference to Ganga Action Plan

Answer: 1. Air Pollution With Special Reference To Dust Particles

The cyclone collector is the device that is used for minimising air pollution by trapping the suspended particles like coarse dust generated due to activities like mining, cement and wood factories. These are dry scrubbers that work on the principle of inertia. Cyclone collector work similar to a centrifuge, but with a continuous feed of dirty air.

Thus, option 1 is correct.

Question 19. Gaseous pollutants can be controlled by

1. Arrestors
2. Electrostatic Precipitators
3. Pyrolysis
4. Incineration

Answer: 2. Electrostatic Precipitators

A gaseous pollutant can be controlled by Electrostatic Precipitator (ESP). It is an electrical device that removes particulate matter present in the exhaust of a thermal power plant. More than 99% of particulate matter can be removed by this method.

Question 20. In a coal-fired power plant, electrostatic precipitators are installed to control the emission of 

1. NOx
2. SPM
3. CO
4. SO₂

Answer: 2. SPM

The electrostatic precipitators are installed to control the emission of Suspended Particulate Matter (SPM) as these can cause various respiratory disorders in humans if released into the air.

Question 21. Which one of the following is the most efficient device to eliminate particulate matter from industrial emission?

1. Cyclonic separators
2. Trajectory separators
3. Pyrolysis
4. Incineration
5. Electrostatic precipitator

Answer: 5. Electrostatic precipitator

An electrostatic Precipitator (ESP) is the most efficient device to eliminate submicron particulates from industrial emissions. It removes the impurities (dust, fibres) by applying a high-voltage electrostatic charge which precipitates the impurities on the charged plates.

” environmental questions and answers pdf”

Question 22. Which of the following is made use in an electrostatic precipitator?

1. Catalysts
2. Absorbers
3. Electrodes
4. Chemicals

Answer: 3. Electrodes

An electrostatic precipitator is used to remove particulate matter present in the exhaust of a thermal power plant. It has electrode wires that are maintained at several thousand volts which produce a corona that releases electrons.

NEET Biology Mcq Chapter Wise

Question 23. In an electrostatic precipitator, very high voltage of electricity is passed through electrodes that produce a corona, which emits …A… . The dust particles present inside the precipitator gains a …B… charge instantly.

1. A–electron, B–positive
2. A–neutron, B–negative
3. A–electron, B–negative
4. A–proton, B–positive

Answer: 3. A–electron, B–negative

In an electrostatic precipitator, electrode wires are provided with an electric current of several thousand volts, which produces a corona that releases electrons (A). These electrons attach to dust particles and gives them a negative charge within a very small fraction of a second.

Question 24. Electrostatic Precipitator (ESP)

1. Removes particulate matter from the exhausts of thermal power
   plants.
2. It has a removal efficiency of 99%.
3. ESP has thin wires and stack of thick metal plates.

Choose the option containing correct statements.

1. 1 and 2
2. 1 and 3
3. 2 and 3
4. 1, 2 and 3

Answer: 4. 1, 2 and 3

All the given statements are correct.

Question 25. The below diagram shows an electrostatic precipitator. Identify A, B, C and D and select the correct option.

1. A–Dust particles, B–Negatively charged wire, C–Discharge corona, D–Collection plate grounded
2. A–Discharge corona, B–Collection plate grounded, C–Dust particles, D–Negatively charged wire
3. A–Discharge corona, B–Negatively charged wire, C–Dust particles, D–Collection plate grounded
4. A–Discharge corona, B–Dust particles, C–Negatively charged wire, D–Collection plate grounded

Answer: 3. A–Discharge corona, B–Negatively charged wire, C–Dust particles, D–Collection plate grounded

Question 26. Choose the correct statement regarding the catalytic converters.

1. Vehicles fitted with catalytic converters must use leaded petrol
2. Platinum, palladium and rhodium are used as catalysts in catalytic converters
3. Catalytic converters reduce the particulate matter
4. Nitrogen gas in the exhaust is converted to nitric oxide by the catalytic converter

Answer: 2. Platinum, palladium and rhodium are used as catalysts in catalytic converters

The statement in option 2 is correct. Other options are incorrect and can be corrected as Catalytic converters are fitted in vehicles for reducing the emission of poisonous gases. As the exhaust passes through, the catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water. Carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas, respectively.

Question 27. Catalytic converters are fitted into automobiles to reduce the emission of harmful gases. Catalytic converters convert leftover hydrocarbons into

1. Carbon Dioxide And Water
2. Carbon Monoxide
3. Methane
4. Carbon dioxide and methane

Answer: 1. Carbon Dioxide And Water

The statement in option 1 is correct. Other options are incorrect and can be corrected as Catalytic converters are fitted in vehicles for reducing the emission of poisonous gases. As the exhaust passes through, the catalytic converter, unburnt hydrocarbons are converted into carbon dioxide and water. Carbon monoxide and nitric oxide are changed to carbon dioxide and nitrogen gas, respectively.

NEET Biology Mcq Chapter Wise

Question 28. Catalytic converters

1. Fitted into automobiles for reducing emission of poisonous gases.
2. Metals like platinum, palladium and rhodium are used as catalysts.
3. On passing through a converter, the nitric oxide in the exhaust splits into nitrogen and oxygen. Carbon monoxide is oxidised to carbon dioxide.
4. Leaded petrol is harmful to catalytic converters as they can inactivate the catalyst.

Choose the option containing correct statements about converters.

1. 1, 2 and 3
2. 2, 3 and 4
3. 1, 3 and 4
4. 1,2,3, and 4

Answer: 4. 1,2,3, and 4

All given statements are correct. Catalytic converters are fitted into automobiles for reducing the emission of poisonous gases. Rhodium and platinum, palladium are examples of catalysts used in catalytic converters. They convert unburnt hydrocarbons into CO₂ and HO₂ and CO and nitric oxide to CO₂ and N₂ gas, respectively. Use of unleaded petrol is however recommended as the lead petrol causes inactivation of the catalyst.

Question 29. Match the following columns.

Answer: 2. A–2, B–1, C–4, D–3

Question 30. Which of the following is not an air pollutant?

1. NO₂
2. SO₂
3. Hydrocarbons
4. CO₂

Answer: 4. CO₂

Carbon dioxide occurs naturally in the atmosphere. It is an essential ingredient in photosynthesis.

Thus, it is not an air pollutant.

NEET Biology Mcq Chapter Wise

Question 31. Air pollution causing photochemical oxidant production includes

1. Carbon Monoxide, Sulphur Dioxide
2. Nitrous Oxide, Nitric Acid Fumes, Nitric Oxide
3. Ozone, Peroxyacetyl Nitrate, Aldehyde
4. Oxygen, chlorine, fuming nitric acid

Answer: 3. Ozone, Peroxyacetyl Nitrate, Aldehyde

Photochemical smog is formed at high temperatures over cities and towns due to still air, emission of oxides of nitrogen and sulphur and hydrocarbon from automobile exhausts and solar energy. Nitrogen dioxide splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecular oxygen to form ozone. Ozone reacts with hydrocarbon to form aldehyde and ketone. Nitrogen oxides, oxygen and ketones combine to form Peroxyacyl Nitrates (PAN). In areas with intense solar radiation, photoelectrical smog forms brown air.

“environment questions “

Question 32. Smog is a combination of

1. Fire And Water
2. Smoke And Fog
3. Smoke And Water
4. Air and water

Answer: 2. Smoke And Fog

Smog is basically derived from the merging of two words; smoke and fog. Smog occurs mainly because of air pollution and can also be defined as a mixture of various gases with dust and water vapour. Smog also refers to hazy air that makes breathing difficult.

Question 33. The basic component of smog may be

1. PAN
2. ozone
3. PBN
4. All of the above

Answer: 4. All of the above

Smog is a highly oxidising polluted atmosphere comprising O3, NO2, PAN (Peroxyacetyl Nitrate) and PBN (Peroxybenzoyl Nitrate).

Question 34. Smog is commonly formed due to JIPMER

1. Mixing Of Ozone With NO₂
2. Deposition Of CO₂ On Condensed Vapour Particles
3. Greenhouse Effect And Global Warming
4. The reaction of oxides of N and S, etc., with sunlight and volatile organic compounds

Answer: 4. Reaction of oxides of N and S, etc., with sunlight and volatile organic compounds

Photochemical smog is formed at high temperatures over cities and towns due to still air, emission of oxides of nitrogen and sulphur and hydrocarbon from automobile exhausts and solar energy. Nitrogen dioxide splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecular oxygen to form ozone. Ozone reacts with hydrocarbon to form aldehyde and ketone. Nitrogen oxides, oxygen and ketones combine to form Peroxyacyl Nitrates (PAN). In areas with intense solar radiation, photoelectrical smog forms brown air.

Question 35. Assertion Smog is commonly formed at places having low temperatures and high pollution of aerosol. Reason (R) It is very common in metropolis cities of India.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. Both A and R are false

Answer: 1. Both A and R are true and R is the correct explanation of A

Both A and R are true and R is the correct explanation of A. Smog is a common problem in many large urban areas, where human activity gives rise to particulates in the air. It can be exacerbated significantly by weather conditions and local geography, which can prevent particulate from being dispersed naturally by wind. It is more closely associated with automobile and industrial emissions, which interact frequently to create the particles that cause smog. Smog is the interaction of light with fine solid or liquid particles in the air, known as aerosols. The most common cause of photochemical smog is the interaction of nitrogen oxides and volatile compounds.

Question 36. Which are the primary constituents of photochemical smog?

1. Carbon dioxide and NO₂
2. Hydrocarbons and CFCs
3. SO₂ and CO
4. NO₂ and hydrocarbons

Answer: 4. NO₂ and hydrocarbons

Photochemical smog is formed at high temperatures over cities and towns due to still air, emission of oxides of nitrogen and sulphur and hydrocarbon from automobile exhausts and solar energy. Nitrogen dioxide splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecular oxygen to form ozone. Ozone reacts with hydrocarbon to form aldehyde and ketone. Nitrogen oxides, oxygen and ketones combine to form Peroxyacyl Nitrates (PAN). In areas with intense solar radiation, photoelectrical smog forms brown air.

NEET Biology Mcq

Question 37. Which is always present in photochemical smog?

1. Ozone
2. CO₂
3. SO₂
4. CH₄

Answer: 1. Ozone

Ozone is generated in the lower atmosphere during the formation of photochemical smog when nitrogen dioxide splits to produce reactive oxygen atoms, which combine with molecular oxygen. Oxygen molecules split under ultraviolet radiations to produce oxygen atoms which combine with molecular oxygen to form ozone. It is always present in photochemical smog.

Question 38. Photochemical smog affects plants by

1. Bleaching Of Leaves And Excess Production Of Pigments
2. Shedding Of Foliage And Increase Of Transpiration
3. Decolourising And Curling Of Leaves
4. Degradation of chlorophyll by ozone

Answer: 4. Degradation of chlorophyll by ozone

Ozone is formed by resultant secondary pollutants in smog and degrades the photosynthetic pigments, i.e. chlorophyll of leaves.

Question 39. Choose the correct sequence of air pollution and its components with the effect it produces.

1. Chemical factory → NO₂ → ozone hole
2. Automobile exhausts → NO₂ → greenhouse effect
3. Heavy industry → CO₂ → acid rain
4. Incinerators → NOx gases → photochemical smog

Answer: 4. Incinerators → NOx gases → photochemical smog

Nitrogen oxides are produced naturally through biological and non-biological activities. Human activity forms nitrogen oxides in the combustion process of industries, automobiles, incinerators and nitrogen fertilisers. Nitrogen oxides give photochemical smog. Thus, the correct sequence of air pollution and its component with the effect it produces is shown in option 4

Question 40. Match the following columns.

Answer: 4. A–3, B–2, C–1

Question 41. Burning of plastics releases

1. CFC
2. SO₂
3. Benzopyrene
4. PCB

Answer: 4. PCB

Polychlorinated Biphenyls (PCB) are released from the burning of plastics.

NEET Biology Mcq

Question 42. The pollutants emitted by jet aeroplanes in the outer atmosphere are known as

1. Smog
2. Photochemical Oxidants
3. Aerosols
4. Loess

Answer: 4. Loess

Chemicals released in the atmosphere with force in the form of mist or vapours are called aerosols. Jet aeroplanes release aerosols which contain CFC.

Question 43. In the ‘wet system’ of removing gaseous pollutants

1. Alkali Fluid Is Used
2. Acidic Fluid Is Used
3. Neutral fluid is used
4. None of the above

Answer: 1. Alkali Fluid Is Used

In wet scrubbing processes for gaseous control, a liquid is used to remove pollutants from an exhaust stream. The removal of pollutants in the gaseous stream is done by absorption by the use of scrubbing reagents such as lime or sodium hydroxide (alkaline nature). Thus, the correct answer is 1.

Question 44. Which of the following statements is true?

1. Benzene hexachloride is a non-biodegradable pollutant.
2. Anthropogenic air pollutants are natural in origin.
3. Carbon monoxide is a primary air pollutant.
4. Sulphur dioxide causes brown air effects during traffic congestion in cities.

Choose the correct option.

1. 1 and 3
2. 1 and 2
3. 2 and 3
4. 2 and 4
5. 1 and 4

Answer: 1. 1 and 3

Statements I and III are true, but II and IV are false because Non-biodegradable pollutants either do not degrade or degrade extremely slowly in the natural environment, e.g. DDT, BHC (Benzene Hexachloride). Anthropogenic pollutants are man made pollutants, e.g. sewage, pesticides, fertilisers, etc. Primary air pollutants are those which enter the air directly from the source, e.g. carbon monoxide. In traffic congested cities, the brown air effect is caused due to oxides of nitrogen.

Question 45. Which of the following is most poisonous?

1. CO
2. CO₂
3. C
4. SO₂

Answer: 1. CO

Carbon monoxide is produced due to incomplete combustion, metallurgical operations and naturally by plants as well as animals. CO combine with haemoglobin and produce carboxy haemoglobin. At 50 ppm carbon monoxide convert 7.5% of haemoglobin into carboxy haemoglobin. It impair oxygen transport resulting in giddiness, headache, decreased vision, cardiovascular malfunctioning and asphyxia. Thus, CO is most poisonous.

NEET Biology Mcq

Question 46. CO is more toxic than CO₂ because 

1. It Affects The Nervous System
2. It Damages Lungs
3. It Reduces The Oxygen Carrying Capacity Of Haemoglobin
4. It forms acid with water

Answer: 3. It Reduces The Oxygen Carrying Capacity Of Haemoglobin

CO is more toxic because it reduces the oxygen carrying capacity of haemoglobin.

Question 47. According to the Central Pollution Control Board (CPCB), particles that are responsible for causing great harm to human health are of diameter 

1. 2.5 micrometres
2. 5.00 micrometres
3. 10.00 micrometres
4. 7.5 micrometres

Answer: 1. 2.5 micrometres

According to Central Pollution Control Board (CPCB), particulate size 2.5 micrometres or less in diameter (PM 2.5) are responsible for causing the greatest harm to human health. These fine particulates can be inhaled deep into the lungs and can cause breathing and respiratory symptoms, irritation inflammations and damage to the lungs and premature deaths.

Question 48. Examples of regional pollution are 

1. Acid Rain
2. Smog
3. Both 1 and 2
4. None of these

Answer: 3. Both 1 and 2

Regional pollutants are those which have been emitted from all sources in a region and have had time to mix, diffuse from their peak concentration and undergo physical, chemical and photochemical reactions. The size of a region is indeterminate, but usually incorporates one or more cities and is on the order of 100 to 10, 000 km2. Examples of regional pollution are acid rain, smog, etc.

Question 49. Rain is called acid rain when its pH is below

1. 7
2. 6.5
3. 6
4. 5.6

Answer: 4. 5.6

Acid rain refers to precipitation with a pH of less than 5.

Question 50. Acid rain is caused by increase in the atmospheric concentration of 

1. CO₂ and CO
2. O₂ and dust
3. SO₂ and NOv
4. SO₃ and CO

Answer: 3. SO₂ and NO₂

Acid rain is rainfall and other forms of precipitation with a pH of less than 5. Acid rain is caused by large scale emission of acidic gases into the atmosphere from thermal power plants, industries and automobiles. The common ones are sulphur dioxide, nitrogen oxides (NO₂), Volatile Organic carbon (VOCs) and hydrogen chloride.

Question 51. The acid rain destroys vegetation because it contains

1. Nitrates
2. H₂SO₄
3. O₂
4. CO

Answer: 2. H₂SO₄

Acid rain contains acidic components, such as sulphuric acid or nitric acid. The type of acid rain that contains water is called wet deposition. Acid rain formed with dust or gasses is called dry deposition. When these rain falls on the soil the soil become acidic. Also the leaves

Question 52. Acid rain occurs above the areas where 

1. There Is Excess Production Of Nh3 And Coal Gas
2. Factories Are Expelling SO₂ In Air
3. There Is an Excess Release Of CO₂ Due To Increase In Combustion And Respiration
4. Excess production of gaseous hydrocarbons

Answer: 2. Factories Are Expelling SO₂ In Air

Acid rain occurs above the area where factories are expelling of sulphur dioxide into the air. These oxides react with water and precipitate in the form of the acid rain. For example, around the Taj Mahal the presence of the Mathura refinery has caused multiple events of acid rain.

NEET Biology MCQ Chapter Wise

Question 53. In acid rain, sulphuric acid accounts for 

1. 100% of acid
2. 70% of acid
3. 50% of acid
4. 30% of acid

Answer: 2. 70% of acid

Acid rain is caused by a chemical reaction. Sulphur dioxide on reaction with water and oxygen forms sulphur trioxide which is rapidly converted into sulphuric acid in the presence of water. It accounts for 70% volume in acid rain. Hence, the correct answer is option 2.

Question 54. It is said that Taj Mahal is getting destroyed due to 

1. Flood In Yamuna River
2. Decomposition Of Marble As A Result Of High Temperature
3. Air pollutant released from oil refinery of Mathura
4. All of the above

Answer: 3. Air pollutant released from oil refinery of Mathura

Threat to Taj Mahal from the Mathura refinery is due to pollutant gases comprising SO₂, H₂S and nitrogen oxides. They would convert CaCO₃ (marble) into calcium sulphate and calcium nitrate.

NEET Biology Mcq

Question 55. Which of the following is the most serious pollutant among sulphur compounds?

1. Oxides of sulphur
2. Carbonyl sulphide
3. Carbon disulphide
4. Sulphates

Answer: 1. Oxides of sulphur

Oxides of sulphur react with water in the atmosphere and form sulphuri cacid which cause rainwater to get acidic and thus oxides of sulphur cause acid rain. Carbonyl sulphide is a colourless gas which decomposes into carbon dioxide and carbon disulphide. Carbon disulphide is a colourless volatile liquid in its pure form. It is not considered to cause any type of pollution. Sulphates are polyatomic ions derived from sulphur and oxygen. Sulphates generally cause water pollution. So, the correct answer is oxides of sulphur.

Question 56. SO₂ pollution affects 

1. Nucleus
2. Mitochondria
3. Ribosome
4. Vacuole

Answer: 2. Mitochondria

SO₂ pollution affects the respiratory system mostly, thus it affects the mitochondria. Higher concentrations of SO₂ can result in temporary breathing impairment for children and adults who are active outdoors. Short-term exposures of individuals to elevated SO₂ levels while at moderate exertion may result in reduced lung function that may be accompanied by such symptoms as wheezing, chest tightness or shortness of breath.

Question 57. A component of living cell affected by pollutant SO₂ is

1. Nucleus
2. All Cell Membrane Systems
3. Cell wall
4. None of the above

Answer: 2. All Cell Membrane Systems

The component of living cell affected by pollutant SO₂ is cell membrane. SO₂ replaces oxygen in cellular materials. It affects structural proteins in the membrane and these changes the membrane permeability.

Question 58. The ciliary passage of the respiratory tract gets damaged by

1. Oxides Of Sulphur
2. Oxides Of Nitrogen
3. Oxides of carbon
4. None of the above

Answer: 1. Oxides Of Sulphur

Oxides of sulphur irritate the respiratory epithelium and impair normal breathing or cause asthma. Thus, oxides of sulphur can damage ciliary passage of respiratory tract.

Question 59. Which of the following are the most suitable indicators of SO₂ pollution in the environment?

1. Algae
2. Fungi
3. Lichens
4. Conifers

Answer: 3. Lichens

Lichens are very sensitive to SO₂ pollution. They are completely destroyed at places where there is SO₂ pollution in the atmosphere. Therefore, they act as very good indicators of SO₂ pollution.

Question 60. SO2 of the atmosphere combines with water to form H SO2 4. When this reaches the soil

1. It Increases Of Ph Of The Soil
2. It decreases the pH of the soil
3. pH remains the same
4. Soil texture changes

Answer: 2. It decreases the pH of the soil

When sulphur dioxide combines with water and air, it forms sulphuric acid, which is the main component of acid rain. When the rain falls on the soil, the soil become acidic resulting in the lower pH of the soil.

Question 61. Which one of the following statements is incorrect in case of the Bhopal tragedy?

1. Methyl isocyanate gas leakage took place
2. Thousands of human beings died
3. Radioactive fallout engulfed Bhopal
4. It took place in the night of December 2/3, 1984

Answer: 3. Radioactive fallout engulfed Bhopal

All options are correct except option 3 because the Bhopal gas tragedy took place in the night of December 2/3, 1984, which was worst chemical disaster in history. People started dying within hours and more than 2000 lives were lost in first few days. Methyl isocyanate gas was the main chemical released that engulfed Bhopal that day.

Question 62. The effect of hydrogen sulphide on man leads to which of the following disease?

1. Paralysis
2. Sterility
3. Blindness
4. None of these

Answer: 4. None of these

HS2 does not accumulate in the body, but repeated/prolonged exposure to moderate levels can cause low blood pressure, headache, loss of appetite and weight. Repeated exposure over time to high levels of HS₂ may cause convulsions, coma, brain and heart damage or even death. So, option 4 is correct.

Question 63. In 1984, Bhopal gas tragedy was caused due to leakage of 

1. Potassium Isocyanate
2. Methyl Isocyanate
3. Sodium monoxide
4. None of the above

Answer: 2. Methyl Isocyanate

Bhopal gas tragedy occurred on 2/3 December, 1984 in which a storage tank containing 36 tonnes of Methyl Isocyanate (MIC) burst in the pesticide manufacturing plant of Union Carbide in Bhopal. MIC is one of the deadliest toxins which when inhaled even in very small doses can kill the animal. It is highly irritating to skin, eyes or mucous membranes and causes death by lung oedema. It is also a carcinogenic agent.

Question 64. What were the effects of the Bhopal gas tragedy?

1. Death of newborn babies
2. Newborn babies were born with deformities
3. Vegetation in the radius of 3.5 sq km around the Union Carbide factory was affected
4. All of the above

Answer: 4. All of the above

Approximately 3598 deaths have resulted from the Bhopal Gas tragedy. Chronic inflammatory damage to the eye and lungs is the main cause. Other effects of this tragedy are the death of newborns and babies were born with deformities and the vegetation in the radius of 3.5 sq. km around the Union Carbide factory was affected.

Thus, option 4 is correct.

Question 65. The TLY (Threshold Limit Value) of methyl isocyanate responsible for the Bhopal gas tragedy is 

1. 0.002 ppm
2. 0.02 ppm
3. 0.2 ppm
4. 0.005 ppm

Answer: 2. 0.02 ppm

Methyl isocyanate is a volatile, toxic chemical used to manufacture carbamate pesticides. Bhopal gas tragedy (2/3 December 1984) is a case of air pollution in which MIC (Methyl Isocyanate) gas released from a fertiliser manufacturing plant of Union Carbide caused the death of approximately 3598 persons. MIC causes irritation in the eyes which may result in blindness, various lung diseases may result in death. Workers exposed to the MIC 8-hours threshold limit value of 0.02 ppm (46) are exposed to approximately 460 mg MIC in a workday.

Question 66. Various atmospheric air borne pollutants may cause

1. Pneumonia
2. Diarrhoea
3. Respiratory Diseases And Allergies
4. Cholera

Answer: 3. Respiratory Diseases And Allergies

Airborne pollutant enters via the respiratory tract in humans and cause respiratory diseases and allergies on the skin.

Question 67. Sulphur dioxide causes

1. Emphysema
2. Bronchitis
3. Asthma
4. All of the above

Answer: 4. All of the above

Sulphur dioxide causes respiratory tract diseases like asthma, bronchitis, cancer, emphysema, etc.

Question 68. Accumulation of fluoride in plant leaves causes

1. Chlorosis
2. Stem Rot
3. Tip burn
4. None of the above

Answer: 3. Stem Rot

Fluoride is an accumulative poison in plant foliage. Accumulation may be gradual over time and causes tip burn in leaves.

Question 69. Which of the following is pollution-related disorder?

1. Silicosis
2. Pneumoconiosis
3. Fluorosis
4. Leprosies

Answer: 1. Silicosis and 3. Fluorosis

(1 & 3) Fluorides are given out during the refining of metals. Fluorides cause fluorosis. This is a pollution-related disorder. When the level of fluoride content in drinking water becomes as high as 3-12 mg/L, the water becomes polluted. It affects teeth as well as bones. Silicosis is caused by inhalation of dust containing free silica or silicon dioxide, especially by workers engaged in mining, pottery, ceramic industry, sandblasting, and building and construction industries. So, both fluorosis and silicosis are pollution-related disorders.

Question 70. Bagassosis is

1. Hypersensitivity Pneumonitis Due To Exposure To Fibrous Cellulose Part Of Crushed Sugarcane
2. Is An Asthma Like Condition Produced Due To Exposure To Flax Or Cotton Fibres
3. Hypersensitivity Pneumonitis Due To Exposure To Damp Hay Or Grain
4. Hypersensitivity pneumonitis due to exposure to paprika

Answer: 1. Hypersensitivity Pneumonitis Due To Exposure To Fibrous Cellulose Part Of Crushed Sugarcane

Bagassosis is an interstitial lung disease, is a type of hypersensitivity pneumonitis due to exposure to the fibrous cellulose part of crushed sugarcane.

Question 71. Which of the following diseases is caused or aggravated by pollution?

1. Bronchitis
2. Rheumatism
3. Scurvy
4. Haemophilia

Answer: 1. Bronchitis

Inflammation of the lining of bronchial tubes causes bronchitis. Particulate matter, a prominent source of air pollution causes pneumoconiosis, byssinosis, emphysema, bronchitis and severe coughing. Rheumatism is a disease of joints. Scurvy is a deficiency disease caused due to the deficiency of vitamin C. Haemophilia is a genetic sex-linked disorder in which blood fails to clot normally.

Question 72. Black foot disease occurs due to 

1. Cadmium
2. Mercury
3. Arsenic
4. Copper

Answer: 3. Arsenic

Black foot disease is caused by excessive consumption of arsenic in water. Black foot disease, with gangrene-like symptoms, affects the feet and sometimes the fingers. It is a rare peripheral vascular disease found mainly in the Province of Taiwan (China). The best prevention for this disease is avoidance of exposure to arsenic by ingesting clean drinking water.

Question 73. ‘Knock knee’ syndrome occurs due to the pollution of 

1. Nitrates
2. Phosphates
3. Fluorides
4. Heavy metals

Answer: 3. Fluorides

Fluorides are given out during the refining of minerals (e.g. aluminium) and can contaminate groundwater. Excess fluorides in drinking water causes teeth deformity, hardened bones and stiff and painful joints (skeletal fluorosis) or knock knee disease.

NEET Biology MCQ Chapter Wise

Question 74. Black lung disease is common in

1. Coal Miners Odisha Jee 2005
2. Refinery Workers
3. Petrochemical Industry
4. Farmers

Answer: 1. Coal Miners Odisha Jee 2005

Black lung is a man-made, occupational lung disease that is contracted by prolonged breathing of coal mine dust. The disease is called ‘black lung’ because it causes the lungs to look black instead of pink. Medically, it is a type of pneumoconiosis called coal worker’s pneumoconiosis.

Question 75. Assertion Fluorides destroy vegetation. Reason (R) Fluorosis hinders respiration.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. Both A and R are false

Answer: 3. A is true, but R is false

A is true, but R is false because, In plants, fluorides combine chemically with Mg 2+ of chlorophyll and hence inhibit photosynthesis. It causes the abscission of leaf and fruit and hence destroy vegetation. In human beings, the typical symptom of excess fluorine (fluorosis) is the mottling of teeth.

Question 76. In a small town, pasture is contaminated with airborne fluorides. Grazing animals in that area will suffer from

1. Dental And Bone Diseases
2. Goitre Disease
3. Thyroid Disease
4. Beriberi

Answer: 1. Dental And Bone Diseases

Fluorides cause fluorosis. It is a disease which is defined by mottling of teeth, and abnormal bones that are liable to fracture because fluorine replaces Ca²⁺ and makes the bones brittle. Fluoride is light airborne particulate matter.

Question 77. Fly-ash is a/an 

1. Insectivorous Plant
2. Light Airborne Particulate Matter
3. New Name Of Orchid Plant
4. Causal organisms of various diseases

Answer: 2. Light Airborne Particulate Matter

Fly ashes are finely divided residues resulting from the combustion of ground or powdered coal. It is discharged as an airborne emission. It is a light airborne particulate matter.

Question 78. Assertion COPD disease is very common in Kanpur. Reason (R) It is disease of respiratory tract occurring due to pollution.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. Both A and R are false

Answer: 1. Both A and R are true and R is the correct explanation of A

Both A and R are true and R is the correct explanation of A. Kanpur is the most polluted city in the country, with high quantities of Respirable Suspended Particulate Matter (RSPM) in the air according to the results of a survey carried out by the Central Pollution Control Board (CPCB) in 2002. Chronic Obstructive Pulmonary Disease (COPD) is a condition characterised by narrowing of the air ways, but these changes are permanent rather than reversible. COPD is caused by exposure to pollutant that produce inflammation.

Question 79. Fibrosis of lung is due to

1. Asbestos And Cement Particles
2. Mercury
3. China Clay
4. Rubber Particles

Answer: 1. Asbestos And Cement Particles

The asbestos and cement particles from industries are added to the air and these are inhaled by workers and people living nearby. These particles form a coating on the internal lining of lungs and bronchioles causing very serious fibrosis which may later lead to cancer.

Question 80. In silicosis, the silica particles can be seen

1. As Needle Shaped Crystal By Light Microscopy
2. As Needle Shaped Crystals Under Polarised Light
3. As Maltese Cross Shaped Crystal By Light Microscopy
4. As Maltese Cross Shaped Crystals Under Polarised Light

Answer: 2. As Needle Shaped Crystals Under Polarised Light

Silicosis is a lung disease caused by breathing-in tiny bits of silica. It is characterised by the fibrotic nodules with the concentric onion skinned arrangement of collagen fibres, central hyalinisation and a cellular peripheral zone with light birefringent particle seen under polarised light.

Question 81. Which of the following ailments is a result of inhalation of fine particulate matter?

1. Irritation
2. Inflammation
3. Damage of lungs and premature deaths
4. All of the above

Answer: 4. Damage of lungs and premature deaths

Fine particulates can be inhaled deep into the lungs and can cause breathing and respiratory symptoms, irritation, inflammations and damage of the lungs and premature deaths.

Question 82. 3, 4-benzopyrene causes

1. Leukaemia
2. Cytosilicosis
3. Lung Cancer
4. Tuberculosis

Answer: 3. Lung Cancer

There are a number of chemicals, which causes lung cancer and one of them is 3,4-benzopyrene. Benzopyrene mutates three positions is the p53 gene, which leads to lung cancer. Hence, the correct option is 3.

NEET Biology MCQ Chapter Wise

Question 83. What is true about the Euro II norms? It is laid down to

1. Control Sulphur At 350 Ppm In Diesel And 150 Ppm In Petrol
2. Reduce Sulphur Level To 50 Ppm In Gasoline
3. Reduce Sulphur Level To 200 Ppm In Diesel And Petrol
4. Reduce sulphur level to 200 ppm in diesel and 100 ppm LPG

Answer: 1. Control Sulphur At 350 Ppm In Diesel And 150 Ppm In Petrol

Euro 2 norms were stipulated to control sulphur content at 350 ppm in diesel and 150 ppm in petrol and aromatic hydrocarbons are to be contained at 42%.

Question 84. All automobiles and fuel (petrol and diesel) were to have met the Euro III emission specification in eleven Indian cities from 1 April 2005 and have to meet the Euro IV norms by

1. 1 April 2007
2. 1 April 2008
3. 1 April 2009
4. 1 April 2010

Answer: 4. 1 April 2010

All automobiles and fuel were to have met the Euro III emission specification in eleven Indian cities from 1 April, 2005 and have to meet the Euro IV norms by 1 April 2010.

Question 85. Air (Prevention and Control of Pollution) Act was ammended in 1987 to include among pollutants

1. Vehicular Exhaust Neet 2020
2. Allergy Causing Pollen
3. Noise
4. Particulates of size 2.5 micrometers or below

Answer: 3. Noise

Air (Prvention and Control of Pollution) Act was ammended in 1987 to include noise as pollutant.

Question 86. Noise is

1. Loud Sound
2. Sound Of High Frequency
3. Unwanted Sound
4. Constant sound

Answer: 3. Unwanted Sound

Noise is defined as an undesired high level of sound. It is a physical form of pollution that affects the receiver directly. Noise or unwanted sound has a value of 80 dB and above.

Question 87. What is the intensity of sound in normal conversation?

1. 10-20 dB
2. 30-60 dB
3. 70-90 dB
4. 120-150 dB

Answer: 3. 70-90 dB

The unit of sound level is decibel. Moderate conversation produces 30–60 dB sound.

NEET Biology MCQ Chapter Wise

Question 88. During day time sound level in the silent zone is about 

1. 20 dB
2. 30 dB
3. 40 dB
4. 50 dB

Answer: 4. 50 dB

Sound is expressed in decibels (dB). A decibel is one-tenth of bel, a unit of measuring electric or acoustic power. The World Health Organisation (WHO) has recommended a noise of less than 75 decibels for industries. The National Pollution Control Board has recommended the following maximum permissible noise level in Indian cities

Question 89. Noise pollution is measured in

1. Decibels
2. Amperes
3. Fathoms
4. Ohm

Answer: 1. Decibels

Noise pollution is measured in decibels (dB).

Question 90. Sound above what level is considered hazardous noise pollution?

1. Above 80 dB
2. Above 120 dB
3. Above 150 dB
4. Below 30 dB

Answer: 1. Above 80 dB

Sound above 80 dB becomes hazardous to humans.

Question 91. Consider the following statements regarding noise.

1. Causes psychological disorders in humans.
2. Causes physiological disorders in humans.
3. Unit of measurement of noise dB.
4. 150 dB is tolerable for humans.

Choose an option containing correct statements.

1. 1 and 4
2. 1 and 2
3. 1, 2 and 3
4. 1 and 3

Answer: 3. 1,2, and 3

All statements are correct except IV because Noise pollution causes psychological and physiological disorders in humans. Noise is measured in dB unit. Above 80 dB noise became hazardous for human.

Question 92. The green muffler is used against which type of pollution?

1. Air
2. Soil
3. Water
4. Noise

Answer: 4. Noise

Green plants are being planted along road side to check noise pollution. This is known as green muffler.

Question 93. The anxiety and stress reactions are caused by 

1. Air Pollution
2. Noise Pollution
3. Water Pollution
4. Nuclear pollution

Answer: 2. Noise Pollution

NEET Biology MCQ Chapter Wise

Noise pollution has several adverse effects on human health as The first effects of noise are anxiety and stress however, in extreme cases it may lead to fright. Noise causes headache by dilating blood vessels of the brain, eye strain by dilating the pupil, digestive spasms through anxiety and high blood pressure by increasing cholesterol level in the blood. Noise can impair the development of nervous system of unborn babies which leads to abnormal behaviour in later life.

Question 94. Assertion Inhabitants close to very busy airports are likely to experience health hazards. Reason (R) Sound level of jet aeroplanes usually exceeds 160 dB.

1. Both A and R are true and R is the correct explanation of A
2. Both A and R are true, but R is not the correct explanation of A
3. A is true, but R is false
4. Both A and R are false

Answer: 1. Both A and R are true and R is the correct explanation of A

Both A and R are true and R is the correct explanation of A. Noise level up to 65 dB (decibel) in a commercial area and up to 75 dB in industrial areas is permitted as per law. Prolonged exposure to noise level to 80 dB or more leads to loss of hearing ability, fatigue, nervousness, fever, hypertension, gastric disorder, increase in cholesterol level and dilation of pupil of the eye. As the jet aeroplanes have the noise up to 150-160 dB or more, the inhabitants in the vicinity of busy airports are likely to experience above health hazards. Maximum noise level is recorded in rockets, i.e. 180 dB.

Question 95. Which of the following physiological manifestations is the result of noise pollution?

1. Dilation of pupil
2. Increase in the rate of heartbeat
3. Constriction of blood vessels
4. All of the above

Answer: 4. All of the above

Because of noise pollution nervous tension, blood pressure and heart trouble increases. It causes constriction of blood vessels and increases the rate of heartbeat. Noise pollution also increases digestive spasms and causes the dilation of the pupils of the eyes. It causes impairment of night vision and decreases the rate of colour perception.

NEET Biology For Environmental Issues Multiple Choice Questions

Question 1. Euro-2 (April 2000) is the emission norm for reducing

1. O3 and CO
2. NO2 and N2O
3. Sulfur and aromatic hydrocarbons
4. CO4 and particulate matter

Answer. 3. Sulfur and aromatic hydrocarbons

Question 2. Corrosion of Taj Mahal is due to the conversion of CaCO3 into

1. CaSO4 and CaNO3
2. Ca(OH)2
3. CaO
4. All of these

Answer. 1. CaSO4 and CaNO3

Question 3. ____________ is highly hazardous to animal health but on plants, this gas does not seem to show adverse effect.

1. CO
2. CO2
3. SO2
4. NO2

Answer. 1. CO

Question 4. The most effective greenhouse gas is

1. CFC
2. CO2
3. Methane
4. O2

Answer. 1. CFC

Question 5. Acid rain is due to

1. 03, PAN
2. Oxides of nitrogen and sulfur
3. Greenhouse effect
4. All of these

Answer. 2. Oxides of nitrogen and sulfur

Question 6. Pollutant responsible for causing phaeophytization is

1. SO2
2. NOX
3. CO2
4. Aeroallergens

Answer. 1. SO2

Question 7. Greenhouse gases are

1. Absorbers of long-wave radiations from the earth
2. Transparent to both solar radiations and long-wave radiations from the earth
3. Absorbers of solar radiations for warming the atmosphere
4. Transparent to emissions from the earth for passage into outer space

Answer. 1. Absorbers of long-wave radiations from the earth

” environmental issues mcqs”

Question 8. Ultraviolet radiations produce the photo oxidant

1. SO2
2. Flouride
3. CO
4. 03

Answer. 4. 03

Question 9. Major air pollutant is

1. CO2
2. N2
3. CO
4. S

Answer. 3. CO

Question 10. The products resulting from the atmospheric rea tions of hydrocarbons and nitrogen oxides in the presence of sunlight are called

1. Primary pollutants
2. Secondary pollutants
3. Tertiary pollutants
4. Non-pollutants

Answer. 2. Secondary pollutants

Question 11. Which of the following is a reddish-brown pollutant gas?

1. NO
2. N2O
3. NO2
4. NH3

Answer. 3. NO2

Question 12. Acid rain

(a) Causes necrosis

(b) Convert chlorophyll-a into pheophytin

(c) Responsible for the formation of PAN

1. Only (a) and (b) are correct
2. Only (b) and (c) are correct
3. Only (a) is correct
4. Only (c) is correct

Answer. 1. Only (a) and (b) are correct

Question 13. Which is not an effect of global warming?

1. More extreme weather condition.
2. Poleward shifting of organism.
3. Rise of sea level.
4. Good fungal growth in soil.

Answer. 4. Good fungal growth in soil.

Question 14. Which of the following conference obtained commitments from different countries for reducing overall greenhouse gas emission at a level 5% below 1990 level by 2008-2012?

1. Kyoto Protocol, 1997
2. Earth Summit, Rio-de-Janeiro, 1992
3. Montreal Protocol, 1987
4. Helsinki Declaration, 1989

Answer. 1. Kyoto Protocol, 1997

Question 15. Which plant has the maximum power of absorbing CO2 and oxides of nitrogen in a polluted area?

1. Eucalyptus
2. Coleus indica
3. Robinia pseudoacacia
4. Daucus carota

Answer. 3. Robinia pseudoacacia

Question 16. Arrange CFC, CH4, N2O, and CO2 in decreasing order according to their contribution in greenhouse effect:

1. CO2 > N2O > CFC > CH4
2. CFC > CO2 > CH4> N2O
3. CH,>CFC>N,O>CO,
4. CO, >CH_>CFC>N,O

Answer. 4. CO, >CH_>CFC>N,O

Question 17. Which is not a natural source of CH, in the environment?

1. Biomass burning
2. Termites
3. Gut of ruminants
4. Rice fields

Answer. 1. Biomass burning

Question 18. The controlled aerobic combustion of wastes inside chambers at temperature of 900-1300°C is known as

1. Incineration
2. Recycling
3. Pyrolysis
4. Sanitary dumping

Answer. 1. Incineration

Question 19. Aerosol is a suspension of

1. Liquid or solid particles of more than 1 mm
2. Liquid drops in air
3. Liquid or solid particles of less than 1 mm
4. Solid particles in air

Answer. 3. Liquid or solid particles of less than 1 mm

Question 20. Ozone hole was first discovered by

1. Robert Augus
2. Molina
3. Farman
4. Rowland

Answer. 3. Farman

Question 21. Which is not an effect of acidic rain in a pond?

1. Increased fungal growth.
2. Decreased insect population.
3. Increased growth of green algae.
4. NO, and SO, saturation.

Answer. 3. Increased growth of green algae.

global warming can significantly be controlled by

Question 22. The smog which is formed at high temperature is

1. London smog
2. Classical smog
3. Los Angeles smog
4. Sulfurous smog

Answer. 3. Los Angeles smog

Question 23. Brown air and gray air is due to the oxides of

1. Sulfur
2. Nitrogen
3. Carbon
4. Phosphorus

Answer. 2. Nitrogen

Question 24. Third pollution is

1. Pollution caused by the addition of an undesirable substance in air, water, soil, or land
2. Deterioration in the quality of air, water, soil, etc., due to removal or reduction in the quality of an important or vital ingredient
3. Ground water pollution due to seepage of minerals, toxic chemicals, and sewage
4. Landscape pollution caused by throwing of rubbish, wastes, and garbage over land

Answer. 4. Landscape pollution caused by throwing of rubbish, wastes, and garbage over land

Question 25. Which is not a control measure to reduce particulate matter in environment?

1. Cyclonic separators
2. Scrubbers
3. Effluent treatment
4. Electrostatic precipitator

Answer. 3. Effluent treatment

Question 26. A chemical weed in troposphere and protectant in stratosphere is

1. CH4
2. 0
3. CFC
4. NO2

Answer. 3. CFC

Question 27. Ganga Action Plan for controlling pollution in Ganges started in

1. 1985
2. 1981
3. 1987
4. 1989

Answer. 1. 1985

Question 28. The presence of 20 or more genera of algae in a water body is an indication of high organic pollution. It is

1. Water index
2. Algal diversity index
3. Pollution index
4. Algal genus index

Answer. 4. Algal genus index

Question 29. The presence of E. coli in water indicates

1. Water is clear
2. Water is fully polluted
3. Inorganic pollution
4. Fecal pollution

Answer. 4. Fecal pollution

Question 30. Blue-baby syndrome is due to

1. Air pollution
2. Soil pollution
3. Thermal pollution
4. Radioactive pollution

Answer. 2. Soil pollution

Question 31. The release of phosphates and nitrates in water bodies (i.e., in rivers and lakes) leads to

1. Nutrient enrichment (eutrophication)
2. Reduced algal growth
3. Increased algal growth
4. Increased growth of decomposers

Answer. 3. Increased algal growth

Question 32. Soil fertility is depleted due to

1. Pan breaking
2. Terracing
3. Intensive agricultur
4. Contour bunding

Answer. 3. Intensive agriculture

Question 33. Spraying of pesticide is an example of

1. Point source water pollution
2. Diffuse water pollution
3. Both (1) and (2)
4. Pyrolysis

Answer. 2. Diffuse water pollution

Question 34. Ecological backlash (or ecological boomerang) is

1. Heat emission due to bomb explosion
2. Production of useful ecological effect by a previously useful chemical
3. Formation of secondary pollutant from the reaction of primary pollutants
4. Production of adverse ecological effect by a previously useful chemical

Answer. 4. Production of adverse ecological effect by a previously useful chemical

Question 35. Minamata disease is due to

1. Oil spill in water
2. Arsenic in the atmosphere
3. Industrial waste having mercury in water
4. Organic waste in drinking water

Answer. 3. Industrial waste having mercury in water

Question 36. Oil slick causes mass-scale death of fishes due to

1. Clogging of gills
2. Disruption of food chain
3. Non-availability of food
4. All of these

Answer. 1. Clogging of gills

Question 37. Wastes may be sealed in concretefilled drums and discharged to a depth of about 500 m. This specific statement is true for

1. Radiation pollutants
2. UV radiation pollutants
3. Particle pollutants
4. All radioactive pollutants

Answer. 4. All radioactive pollutants

Question 38. Bone cancer is caused by

1. Iodine 127
2. Strontium 90
3. Cesium 137
4. None of these

Answer. 2. Strontium 90

Question 39. As a general rule, ionizing radiation is most damaging to

1. Mature, stable cells
2. Actively dividing cells
3. Highly specialized cells
4. Cells in which food is stored

Answer. 2. Actively dividing cells

Question 40. Volcanic eruptions let out large quantities of

1. Harmful dust and sulfurous gases
2. Harmful dust and nitrous gases
3. Harmful dust and carbonous gases
4. Harmful dust and phosphorous gases

Answer. 3. Harmful dust and carbonous gases

Question 41. Painful skeletal deformity called itai-itai is caused due to

1. Cd
2. Hg
3. CO
4. NO2

Answer. 1. Cd

Question 42. Acoustic zoning is related with

1. Soil pollution
2. Noise pollution
3. Water pollution
4. Air pollution

Answer. 2. Noise pollution

environmental questions

Question 43. Montreal Protocol was aimed to

1. Reduce greenhouse gases
2. Limit the production and use of ODS
3. Mitigate climatic change
4. Implement Agenda 21

Answer. 2. Limit the production and use of ODS

Question 44. The Government of India has introduced a concept to work closely with local communities for protection and management of forests called

1. Jhum cultivation
2. Chipko Movement
3. Appiko Movement
4. Joint Forest Management

Answer. 4. Joint Forest Management

Question 45. The National Forest Policy of India has recommended percent forest cover for hilly areas.

1. 67
2. 33
3. 19.4
4. 30

Answer. 1. 67

Question 46. To spread information and help on the practice of integrated organic farming is started by a group of farmers in

1. Haryana
2. Bangalore
3. Delhi
4. Jodhpur

Answer. 1. Haryana

Question 47. Find the odd one out with respect to e-waste:

1. India
2. Pakistan
3. China
4. America

Answer. 4. America

Question 48. Minerals, metals, and fossil fuels are which type of resources of energy?

1. Renewable
2. Non-renewable
3. Biodegradable
4. Degradable

Answer. 2. Non-renewable

Question 49. Thermal pollution is caused by

1. Power plants
2. Industries
3. Automobiles
4. All of the above

Answer. 4. All of the above

Question 50. The addition of any substance to water which leads to change in its physical and chemical characteristics is defined as water pollution. It results in

1. Decreased turbidity
2. Increased oxygenation
3. Increased photosynthesis
4. Increased turbidity and deoxygenation

Answer. 4. Increased turbidity and deoxygenation

Question 51. Which of the following is not a greenhouse gas?

1. CH4
2. N2O
3. H2O
4. CO2

Answer. 3. H2O

Question 52. High BOD indicates

1. Highly polluted water
2. Less pollution in H2O
3. Less sewage
4. Less microorganism

Answer. 1. Highly polluted water

Question 53. Increasing the concentration along food chain is of accumulated pollutant

1. Biomagnification
2. Bioaccumulation
3. Eutrophication
4. Biodiversity

Answer. 1. Biomagnification

Question 54. Which one of the following is a renewable source of energy?

1. Petroleum
2. Coal
3. Nuclear fuel
4. Trees

Answer. 4. Trees

Question 55. Spraying of DDT produces pollution of

1. Air only
2. Air and soil only
3. Air, soil, and water
4. Air and water only

Answer. 3. Air, soil, and water

Question 56. Sewage water is purified for recycling by the action of

1. Light
2. Microorganisms
3. Aquatic plants
4. Fishes

Answer. 2. Microorganisms

Question 57. Which one is not dangerous?

1. Biopollutants
2. Ozone layer
3. Nuclear blast
4. Deforestation

Answer. 2. Ozone layer

Question 58. Which of the following a set is greenhouse gases?

1. CFC, CH4, CO2, N20
2. CO2, CH4, N2, O2
3. CO2, CH4, N2O3
4. CO2, CFC, N2, O2

Answer. 1. CFC, CH4, CO2, N20

Question 59. Acid rain is due to pollution by

1. CO2
2. SO2 and NO2
3. Dust particles
4. Automobiles

Answer. 2. SO2 and NO2

Question 60. Which of the following is a biodegradable pollutant?

1. Sewage
2. Plastic
3. Polythene
4. DDT

Answer. 1. Sewage

Question 61. The most hazardous metal pollutant of automobile exhaust is

1. Cadmium
2. Lead
3. Mercury
4. Copper

Answer. 2. Lead

Question 62. Air quality indicator is

1. Lichen
2. Moss
3. Algae
4. None of these

Answer. 1. Lichen

Question 63. Blood hemoglobin has high affinity for

1. CO2
2. CO
3. O2
4. H2

Answer. 2. CO

Question 64. Minamata disease caused due to water pollution is due to

1. Lead poisoning
2. Arsenic chloride poisoning
3. Mercury poisoning
4. Ammonia pollution

Answer. 3. Mercury poisoning

Question 65. Effect of pollution is first marked on

1. Microorganisms
2. Green vegetation of an area
3. Food crop
4. None of these

Answer. 2. Green vegetation of an area

Question 66. Pollution is not caused by

1. Thermal power plant
2. Automobile
3. Radioactive power plant
4. Hydroelectric power plant

Answer. 4. Hydroelectric power plant

Question 67. Taj Mahal marble is affected by

1. SO2
2. O2
3. O3
4. NO2

Answer. 1. CO2

Question 68. Minamata disease first occurred in

1. Japan
2. China
3. Korea
4. Russia

Answer. 1. Japan

Question 69. Increase in the BOD of water reservoir is due to

1. Algae
2. Soil
3. Moss
4. Waste product

Answer. 4. Waste product

Question 70. Number of wildlife is continuously decreasing. What is the main reason behind this?

1. Predation
2. Cutting down of forest
3. Destruction of habitat
4. Hunting

Answer. 3. Destruction of habitat

Question 71. One of the following is associated with the conservation of forests. Find the one.

1. Kaziranga
2. Ghana
3. Silent valley
4. Gir

Answer. 3. Silent valley

Question 72. Which one of the following is a pair of endangered species?

1. Garden lizard and Mexican poppy
2. Rhesus monkey and sal tree
3. Indian peacock and carrot grass
4. Hornbill and Indian aconite

Answer. 4. Hornbill and Indian aconite

Question 73. If the Bengal Tiger becomes extinct,

1. Hyenas and wolves will become scare
2. The wild areas will be safe for man and domestic animals
3. Its gene pool will be lost forever
4. The populations of beautiful animals such as deers will get stabilized

Answer. 3. Its gene pool will be lost forever

Question 74. If high-altitude birds become rare or extinct, the plants which may disappear along with them are

1. Pine
2. Oak
3. Orchids
4. Rhododrons

Answer. 4. Rhododrons

environment questions

Question 75. Which one of the following pairs of geographical areas shows maximum biodiversity in our country?

1. Sunderbans and Rann of Kutch
2. Eastern Ghats and West Bengal
3. Eastern Himalaya and Western Ghats
4. Kerala and Punjab

Answer. 3. Eastern Himalaya and Western Ghats

Question 76. One of the ex situ conservation methods for endangered species is

1. Wildlife sanctuaries
2. Biosphere reserves
3. Cryopreservation
4. National parks

Answer. 3. Cryopreservation

Question 77. Reason for the elimination of wildlife is

1. Deforestation
2. Forest fire
3. Floods
4. Less rainfall

Answer. 1. Deforestation

Question 78. The main reason of disturbance of biological diversity is

1. Greenhouse effect
2. Hunting
3. Soil erosion
4. Destruction of natural habitats

Answer. 4. Destruction of natural habitats

Question 79. The best method to preserve the wild relatives of plants is

1. By growing them in natural habitats
2. Gene library
3. By storing seeds
4. Cryopreservation

Answer. 1. By growing them in natural habitats

Question 80. Species diversity is the maximum in

1. Tropical rain forest
2. Temperate forest
3. Deserts
4. Hill slopes

Answer. 1. Tropical rain forest

Question 81. According to the Forestry Commission report 1997, the total forest cover of India was

1. 11%
2. 19.5%
3. 17%
4. 18.7%

Answer. 2. 19.5%

Question 82. What shall be the effect of destruction of wildlife?

1. Wild gene of disease resistance will not be obtained
2. Soil erosion
3. Floods
4. Greenhouse effect

Answer. 1. Wild gene of disease resistance will not be obtained

Question 83. The reason behind the occurrence of endemic species in South America and Australia is

1. The species has been extinct from other regions
2. Continental separation
3. There is no terrestrial route to these places
4. Retrogressive evolution

Answer. 2. Continental separation

Question 84. In your opinion, which is the most effective way to conserve the plant diversity of an area?

1. By creating biosphere reserve
2. By creating botanical garden
3. By developing seed bank
4. By tissue culture method

Answer. 1. By creating biosphere reserve

Question 85. The Biodiversity Act of India was passed by the Parliament in the year

1. 2002
2. 1992
3. 1996
4. 2000

Answer. 1. 2002

Question 86. According to the IUCN Red List, what is the status of red panda (Ailurus fulgens)?

1. Critically species
2. Vulnerable species
3. Extinct species
4. Endangered species

Answer. 4. Endangered species

Question 87. One of the most important functions of botanical gardens is that

1. They provide a beautiful area for recreation
2. One can observe tropical plants there
3. They allow ex situ conservation of germplasm
4. They provide the natural habitat for wildlife

Answer. 3. They allow ex situ conservation of germplasm

Question 88. Which of the following pairs of animal and plant represents endangered organisms in India?

1. Cinchona and leopard
2. Banyan and black buck
3. Bentinckia nicobarica and red panda
4. Tamarind and rhesus monkey

Answer. 3. Bentinckia nicobarica and red panda

Question 89. Which one of the following is not included under in situ conservation?

1. Biosphere reserve
2. National park
3. Sanctuary
4. Botanical garden

Answer. 4. Botanical garden

Question 90. Which one of the following is the correctly matched pair of endangered animal and national park?

1. Wild ass-Dudhwa National Park
2. Great Indian-Keoladeo National Park Bustard
3. Lion-Corbett National Park
4. Rhinoceros-Kaziranga National Park

Answer. 4. Rhinoceros-Kaziranga National Park

Question 91. Which of the following is considered a hot-spot of biodiversity in India?

1. Eastern Ghats
2. Aravalli Hills
3. Western Ghats
4. Indo-Gangetic Plain

Answer. 3. Western Ghats

Question 92. Identify the odd combination of the habitat and the particular animal concerned:

1. Rann of Kutch-Wild ass
2. Dachigam National Park-Snow leopard
3. Sunderbans-Bengal tiger
4. Periyar-Elephant

Answer. 2. Dachigam National Park-Snow leopard

Question 93. Which one of the following pairs of organisms are exotic species introduced in India?

1. Nile perch, Ficus religiosa
2. Ficus religiosa, Lantana camara
3. Lantana camara, Water hyacinth
4. Water hyacinth, Prosopis cinereia

Answer. 3. Lantana camara, Water hyacinth

Question 94. Which one of the following is not observed in biodiversity hotspots?

1. Lesser inter-specific competition
2. Species richness
3. Endemism
4. Accelerated species loss

Answer. 1. Lesser inter-specific competition

Question 95. Tiger is not a resident in which one of the following national parks?

1. Jim Corbett
2. Ranthambhor
3. Sunderbans
4. Gir

Answer. 4. Gir

Question 96. Which one of the following is an example of ex situ conservation?

1. Wildlife sanctuary
2. Seed bank
3. Sacred groves
4. National park

Answer. 2. Seed bank

Question 97. The Indian Rhinoceros are a natural inhabitant of which Indian state?

1. Uttar Pradesh
2. Himachal Pradesh
3. Assam
4. Uttarakhand

Answer. 3. Assam

Question 98. Which of the following is the non-conventional source of energy?

1. Coal
2. Petroleum
3. Electricity from nuclear power plants
4. Solar radiations

Answer. 4. Solar radiations

Question 99. Petroleum resource is

1. Renewable
2. Non-renewable
3. Synthetic and biodegradable
4. Infinite and unconventional,

Answer. 2. Non-renewable

bod is related to

Question 100. Biological oxygen demand (BOD) is a measure of

1. Industrial wastes poured into water bodies
2. Extent to which water is polluted with organic compounds
3. Amount of carbon monoxide inseparably combined with hemoglobin
4. Amount of oxygen needed by green plants during night

Answer. 2. Extent to which water is polluted with organic compounds

Question 101. In almost all Indian metropolitan cities such as Delhi, the major atmospheric pollutant/s is/are

1. Suspended particulate matter (SPM)
2. Oxides of sulfur
3. Carbon dioxide and carbon monoxide
4. Oxides of nitrogen

Answer. 1. Suspended particulate matter (SPM)

Question 102. Nitrogen oxides produced from the emission of automobiles and power plants are the source of fine air borne particles which lead to

1. Photochemical smog
2. Dry acid deposition
3. Industrial smog
4. Wet acid deposition

Answer. 2. Dry acid deposition

Question 103. A lake with an inflow of domestic sewage rich in organic waste may result in

1. Drying of the lake very soon due to algal bloom
2. An increased production of fish due to lots of nutrients
3. Death of fish due to lack of oxygen
4. Increased population of aquatic food web organisms

Answer. 3. Death of fish due to lack of oxygen

Question 104. Minamata disease was caused due to the consumption of

1. Sea food containing a lot of cadmium
2. Fish contaminated with mercury
3. Oysters with a lot of pesticide
4. Sea food contaminated with selenium

Answer. 2. Fish contaminated with mercury

Question 105. Which one of the following statements pertaining to pollutants is correct?

1. DDT is a non-biodegradable pollutant.
2. Excess fluoride in drinking water causes osteoporosis.
3. Excess cadmium in drinking water causes black foot disease.
4. Methyl mercury in water may cause “itai itai” disease.

Answer. 1. DDT is a non-biodegradable pollutant.

Question 106. If CO2 is absent in the atmosphere of earth, then

1. Temperature will decrease
2. Temperature will increase.
3. Plants will flourish well
4. No effect

Answer. 1. Temperature will decrease

Question 107. CO is harmful because

1. It forms stable compound with hemoglobin
2. It blocks mitosis
3. It is mutagenic
4. It causes defloation

Answer. 1. It forms stable compound with hemoglobin

Question 108. Besides CH, and CO2, other greenhouse gas from agriculture area is

1. SO2
2. NH3
3. NO2
4. CFC

Answer. 3. NO2

Question 109. Temperature variation in Pacific Ocean in present time is called

1. Cyclone effect
2. El Niño effect
3. Greenhouse effect
4. Gaudikov’s effect

Answer. 2. El Niño effect

Question 110. Sewage purification is performed by

1. Microbes
2. Fertilizers
3. Antibiotics
4. Antiseptics

Answer. 1. Microbes

Question 111. The best economic method to harvest the solar energy is

1. Solar cell
2. Energy plantation
3. Cultivation of sugarcane; then energy obtained by burning it
4. Solar cooker

Answer. 2. Energy plantation

Question 112. The Bhopal Gas Tragedy is related with

1. Methane
2. Carbon monoxide
3. Methyl isocyanate (MIC)
4. SO2

Answer. 3. Methyl isocyanate (MIC)

Question 113. The concentration of DDT is the highest in

1. Primary consumer
2. Producers
3. Top consumer
4. Decomposers

Answer. 3. Top consumer

Question 114. Lichens can be used

1. Bioindicator for water and air pollution
2. Initial vegetation for waste lands
3. Source of wood
4. To check air pollution

Answer. 1. Bioindicator for water and air pollution

Question 115. What is phytotron?

1. A device to grow plants in controlled environment.
2. Growing plants in greenhouse.
3. Radiation chamber to induce mutations.
4. Apparatus to study the effect of light on plants.

Answer. 1. A device to grow plants in controlled environment.

Question 116. Which of the following is a secondary pollutant?

1. PAN
2. CO
3. NO2
4. SO2

Answer. 1. PAN

Question 117. Maximum DDT is present in birds feeding on

1. Fishes
2. Meat
3. Insects
4. Seeds

Answer. 1. Fishes

Question 118. Which one is associated with occupational hazard?

1. Fluorosis
2. Pneumoconiosis
3. Silicosis
4. Asthama

Answer. 2. Pneumoconiosis

Question 119. Greenhouse effect is

1. Gardening outside the house
2. Global cooling
3. Global warming
4. Green color house

Answer. 3. Global warming

environmental questions and answers pdf

Question 120. What is BOD?

1. The amount of O2 utilized by organisms in water.
2. The amount of O2 utilized by microorganisms for decomposition.
3. The total amount of O2 present in water.
4. All of the above.

Answer. 2. The amount of O2 utilized by microorganisms for decomposition.

Question 121. What is the intensity of sound in normal conversation?

1. 10-20 db
2. 30-60 db
3. 70-90 db
4. 120-150 db

Answer. 2. 30-60 db

Question 122. Which of the following is absent in polluted water?

1. Hydrilla
2. Water hyacinth
3. Larva of stone fly
4. Blue green algae

Answer. 3. Larva of stone fly

Question 123. The maximum greenhouse gas is released by which country?

1. India
2. France
3. USA
4. Britain

Answer. 3. USA

Question 124. Lead concentration in blood is considered alarming if it is

1. 30 mg/100 ml
2. 4-6 mg/100 ml
3. 10 mg/100 ml
4. 20 mg/100ml

Answer. 3. 10 mg/100 ml

Question 125. In 1984, the Bhopal Gas Tragedy took place because methyl isocyanate

1. Reacted with ammonia.
2. Reacted with CO2
3. Reacted with water
4. Reacted with DDT

Answer. 3. Reacted with water

Question 126. Blood analysis of a patient reveals an unusually high quantity of carboxyhemoglobin content. Which of the following conclusion is the most likely to be correct? The patient has been inhaling polluted air containing unusually high content of

1. Carbon monoxide
2. Carbon disulfide
3. Chloroform
4. Carbon dioxide

Answer. 1. Carbon monoxide

Question 127. The common indicator organism of water pollution is

1. Entamoeba histolytica
2. Lemna paucicostata
3. Eichhornia crassipes
4. Escherichia coli

Answer. 4. Escherichia coli

Question 128. Which one of the following pairs in mismatched?

1. Nuclear power – Radioactive wastes
2. Solar energy – Greenhouse effect
3. Fossil fuel burning – Release of CO2
4. Biomass burning-Release of CO2

Answer. 2. Solar energy – Greenhouse effect

Question 129. Identify the correctly matched pair?

1. Kyoto Protocol-Climatic change
2. Montreal Protocol – Global warming
3. Basal convention Biodiversity conservation
4. Ramsar convention-Ground water pollution

Answer. 1. Kyoto Protocol-Climatic change

Question 130. Prolonged liberal irrigation of agricultural fields is likely to create the problem of

1. Acidity
2. Aridity
3. Salinity
4. Metal toxicity

Answer. 3. Salinity

Question 131. Which of the following is not used for the disinfection of drinking water?

1. Chlorine
2. Ozone
3. Chloramine
4. Phenyl

Answer. 4. Phenyl

Question 132. The limit of BOD prescribed by the Central Pollution Control Board for the discharge of industrial and municipal waste waters into natural surface waters is 

1. < 100 ppm
2. <30 ppm
3. <3 ppm
4. < 10 ppm

Answer. 2. <30 ppm

Question 133. The “blue baby” syndrome results from

1. Excess of dissolved oxygen
2. Excess of TDS (total dissolved solids)
3. Excess of chloride
4. Methaemoglobinaemia

Answer. 4. Methaemoglobinaemia

Question 134. Montreal Protocol, which calls for appropriate action to protect the ozone layer from human activities, was passed in the year

1. 1988
2. 1985
3. 1986
4. 1987

Answer. 4. 1987

Question 135. Photochemical smog pollution does not contain

1. Carbon dioxide
2. PAN (peroxy acyl nitrate)
3. Ozone
4. Nitrogen dioxide

Answer. 1. Carbon dioxide

Question 136. In a coal-fired power plant, electrostatic precipitators are installed to control the emission of pollution?

1. CO
2. SO2
3. NO
4. SPM

Answer. 4. SPM

Question 137. Which one of the following is not a bioindicator of water

1. Sewage fungus
2. Sludge worms
3. Blood-worms
4. Stone flies

Answer. 4. Stone flies

Question 138. Which one of the following is the correct percentage of the two (out of the total of four) greenhouse gases that contribute to the total global warming?

1. N,O 6%, CO, 86%
2. Methane 20%, N2O 18%
3. CFCs 14%, methane 20%
4. CO2 40%, CFCs 30%

Answer. 3. CFCs 14%, methane 20%

Question 139. The World Summit on Sustainable Development (2002) was held in

1. Argentina
2. South Africa
3. Brazil
4. Sweden

Answer. 2. South Africa

Question 140. About 70% of total global carbon is found in

1. Ocean
2. Forests
3. Desert
4. Rain forest

Answer. 1. Ocean

Question 141. A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this?

a. Lots of urea and phosphate fertilizers were used in the crops in the vicinity.

b. The area was sprayed with DDT by an aircraft.

c. The lake water turned green and stinky.

d. Phytoplankton population in the lake declined initially thereby greatly reducing photosynthesis.

Which two of the above were the main causes of fish mortality in the lake?

1. (a), (c)
2. (a), (b)
3. (b), (c)
4. (c), (d)

Answer. 1. (a), (c)

Question 142. According to the Central Pollution Control Board (CPCB), which particulate size in diameter (in micrometers) of the air pollutants is responsible for the greatest harm to human health?

1. 1.0 or less
2. 5.2-2.5
3. 2.5 or less
4. 1.5 or less

Answer. 3. 2.5 or less

Question 143. The Montreal Protocol aims at

1. Control of CO2 emission
2. Reduction of ozone depleting substances
3. Biodiversity conservation
4. Control of water pollution

Answer. 2. Reduction of ozone depleting substances

Question 144. The Chipko Movement was launched for the protection of

1. Wet lands
2. Grasslands
3. Forests
4. Livestock

Answer. 3. Forests

Question 145. Steps taken by the Government of India to control air pollution include

1. Use of non-polluting compressed natural gas (CNG) only as fuel by all buses and trucks
2. Compulsory mixing of 20% ethyl alcohol with petrol and 20% biodiesel with diesel
3. Compulsory PUC (pollution under control) certification of petrol driven vehicles which tests for carbon monoxide and hydrocarbons
4. Permission to use only pure diesel with a maximum of 500 ppm sulfur as fuel for vehicles

Answer. 1. Use of non-polluting compressed natural gas (CNG) only as fuel by all buses and trucks

Question 146. Biochemical oxygen demand (BOD) in river water

1. Increases when sewage gets mixed with river water
2. Remains unchanged when algal bloom occurs
3. Has no relationship with the concentration of oxygen in water
4. Gives a measure of Salmonella in water

Answer. 1. Increases when sewage gets mixed with river water

Question 147. DDT residues are rapidly passed through food chain causing biomagnification because DDT is

1. Water soluble
2. Fat soluble
3. Moderately toxic

Non-toxic to aquatic animals

Answer. 2. Fat soluble

Question 148. Global agreement in specific control strategies to reduce the release of ozone depleting substances was adopted by 

1. The Vienna Convention
2. Rio de Janeiro Conference
3. The Montreal Protocol
4. The Koyoto Protocol

Answer. 3. The Montreal Protocol

Question 149. Breeding of crops with high levels of minerals, vitamins, and proteins is called

1. Somatic hybridization
2. Biofortification
3. Biomagnification
4. Micropropagation

Answer. 2. Biofortification

Question 150. The two gases making the highest relative contribution to the greenhouse gases are

1. CO2 and CH4
2. CH, and N2O
3. CFCs and N2O
4. CO2 and N2O

Answer. 1. CO2 and CH4

Question 151. A renewable exhaustible natural resource is

1. Coal
2. Petroleum
3. Minerals
4. Forest.

Answer. 4. Forest.

Question 152. When domestic sewage mixes with river water,

1. The increased microbial activity releases micronutrients such as iron
2. The increased microbial activity uses up dissolved oxygen
3. The river water is still suitable for drinking as impurities are only about 0.1%
4. Small animals such as rats will die after drinking river water

Answer. 2. The increased microbial activity uses up dissolved oxygen

Question 153. Measuring BOD is a method used for

1. Working out the efficiency of oil driven automobile engines.
2. Measuring the activity of Saccharomyces cerevisiae in producing curd on a commercial scale
3. Working out the efficiency of RBCs about their capacity to carry oxygen
4. Estimating the amount of organic matter in sewage water

Answer. 4. Estimating the amount of organic matter in sewage water

Question 154. Which one of the following is a wrong statement?

1. Ozone in the upper part of atmosphere is harmful to animals.
2. Greenhouse effect is a natural phenomenon.
3. Eutrophication is a natural phenomenon in fresh water bodies.
4. Most of the forests have been lost in tropical areas.

Answer. 1. Ozone in the upper part of atmosphere is harmful to animals.

Question 155. Which one of the following areas in India is a hotspot of biodiversity?

1. Gangetic Plain
2. Sunderbans
3. Western Ghats
4. Eastern Ghats

Answer. 3. Western Ghats

Question 156. Select the correct statement about biodiversity:

1. The desert areas of Rajasthan and Gujarat have a very high level of desert animal species as well as numerous rare animals.
2. Large scale planting of Bt cotton has no adverse effect on biodiversity.
3. Western Ghats have a very high degree of species richness and endemism.
4. Conservation of biodiversity is just a fad pursued by the developed countries.

Answer. 3. Western Ghats have a very high degree of species richness and endemism.