NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions


Deuteromycetes are known as fungi imperfecti because

  • their zygote undergoes meroblastic and holoblastic cleavage

  • only asexual stages are known

  • they have aseptate myceliun

  • they are autotrophic


only asexual stages are known

Deuteromycetes are commonly known as imperfect fungi because only the asexual or vegetative stages of these fungi are known. The deuteromycetes reproduce only by asexual spores known as conidia. The mycelium is septate and branched. Some members are saprophytes or parasites while a large number of them are decomposers of litter and help in mineral cycling. Some examples are Alternaria, Colletotriclmm and Trichoderma.


The microscope usually used for seeing living cells or tissues is

  • compound microscope

  • electron micrscope

  • phase contrast microscope

  • light microscope.


phase contrast microscope

Phase contrast microscope was developed by Zemicke (1935, Nobel Prize 1953) to observe living cells and the events occurring in them (e.g., Spindle formation, movement of chromosomes, endocytosis, exocytosis). It is similar to optical microscope except that it has an annular diaphragm in the condenser and a transparent phase plate at the back focal plane of objective. The microscope converts differences in refractive indices into differences in brightness.


Photorespiration shows formation of

  • sugar but not ATP

  • ATP but not sugar

  • both ATP and sugar

  • neither ATP nor sugar


neither ATP nor sugar

Photorespiration is the light dependent process of oxygenation of ribulose biphosphate (RuBP) and release of carbon dioxide by the photosynthetic organs of a plant. Normally photosynthetic organs do the reverse in the light, i.e., uptake of CO2 and release of O2 At high temperature, RuBP carboxylase functions as oxygenase and instead of fixing carbon dioxide (C4 cycle), oxidises ribulose 1, 5-biphosphate to produce a 3-carbon phosphoglyceric acid and a 2-carbon phosphoglycolate. Photorespiration does not produce energy or reducing power. Rather, it consumes energy. Further, it undoes the work of photosynthesis. There is 25% loss of fixed CO2. Therefore, photorespiration is a highly wasteful process. This happens only in case of C4 plants. C4 plants have overcome the problem of photorespiration.


In aerobic respiration, total number of ATP molecules formed from 1 glucose molecule is

  • 28

  • 32

  • 36

  • 30



The net gain from complete oxidation of a glucose molecule in aerobic respiration is 36 ATP molecules. 10 molecules of NADH, (2 from Glycolysis + 8 from Krebs' cycle) yield = 10 x 3= .30 ATP, 2 molecules of FADH, yield = 2x 2 = 4 ATP and glycolysis also yields 2 ATP. Therefore, total release of ATP per hexose will be = 30 + 4 + 2 = 36 ATP.


Which of the following is correctly matched

  • Monstera- Fibrous root

  • Dahlin- Fasciculated root

  • Azadirachta- Adventitious root

  • Basil- Prop roots


Monstera- Fibrous root

Fasciculated root is a type of adventitious root. In this case, roots are swollen which occur in clusters from lower nodes of stems, e.g, Asparagus, Dahlia, etc.


Which of the following is correct regarding respiration in adult frog

  • In water- Skin, gills

  • On land - Skin, buccal cavity

  • In water- Skin, buccal cavity

  • On land- Skin, lungs, gills


On land - Skin, buccal cavity

In frog three types of respiration occurs to suit its amphibious mode of life. These are cutaneous, buccopharyngeal and pulmonary respiration. Cutaneous respiration occurs through the thin, moist, highly vascular and naked skin. It takes place in water as well as on land. Buccopharyngeal respiration occurs on land via thin, vascular, moist lining of buccopharyngeal cavity. Pulmonary respiration takes place when the frog is outside the water. It occurs by lungs of adult frog.


Abscisic acid is known as the stress hormone because it

  • breaks seed dormancy

  • induces flowering

  • promotes leaf fall

  • promotes closure of stomata


promotes closure of stomata

Abscisic acid acts as a general plant growth inhibitor and an inhibitor of plant metabolism. ABA inhibits seed germination. ABA stimulates the closure of stomata in the epidermis and increases the tolerance of plants to various kinds of stresses. Therefore, it is also called the stress hormone.


One of the world's most poisonous fish toxins is released by

  • clown fish

  • eel fish

  • sword fish

  • puffer fish


puffer fish

The majority of pufferfish species are toxic and some are among the most poisonous vertebrates in the world. In certain species, the internal organs, such as liver, and sometimes their skin, contain tetrodotoxin and are highly toxic to most animals when eaten; nevertheless, the meat of some species is considered a delicacy in Japan, Korea, and China when prepared by specially trained chefs who know which part is safe to eat and in what quantity.


Which of the following is correctly labelled

  • A: Reissner's membrane

  • B: Scala vestibuli

  •  C : Basilar membrane

  • D: Tectorial membrane


D: Tectorial membrane

A- Basilar membrane
B- Scala media
C- Reissner's membrane
D- Tectorial membrane


Na+/K+ pump is associated with

  • passive transport

  • active transport

  • osmosis

  • imbibition


active transport

Sodium-potassium pump (Na-K) is a membrane transport protein that exchanges sodium ions (Na+) for potassium ions (K+). It transports 3 Na+ outwards for 2K+ into the cell, thus maintaining the differential concentrations of each ion across the plasma membrane. The process requires energy in the form of ATP, being a form of active transport.