NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions


Feedback inhibition of enzymes is affected by which ofthe following

  • Enzyme

  • Substrate

  • End products

  • Intermediate end products


End products

Feedback inhibition is the phenomenon where the output of a process is used as an input to control the behavior of the process itself, oftentimes limiting the production of more product. Although negative feedback is used in the context of inhibition, negative feedback may also be used for promoting a certain process


Net yield of ATP molecules in aerobic respiration during Krebs cycle per glucose molecule is

  • 2 ATP molecules

  • 8 ATP molecules

  • 36 ATP molecules

  • 38 ATP molecules


2 ATP molecules

Net ATP produced during the kreb cycle is 2 ATP (GTP). One ATP obtained from each Acetyl Co. enzyme A


In a CAM plant, the concentration of organic acid

  • increases during the day

  • decreases or increases during the day

  • increases during night

  • decreases during any time


increases during night

Crassulacean acid metabolism, also known as CAM photosynthesis, is a carbon fixation pathway that evolved in some plants as an adaptation to arid conditions. In a plant using full CAM, the stomata in the leaves remain shut during the day to reduce evapotranspiration, but open at night to collect carbon dioxide (CO2).


The discovery of gibberellins is related with one of the following

  • blast disease of rice

  • rust disease of wheat

  • bakane disease of rice

  • early blight disease of potato


bakane disease of rice

Kurosawa, a Japanese botanist, discovered gibberellin while investigating the rice foolish seedling disease in which spindly seedlings are formed due to GA like compounds produced by the fungus ( Gibberella fujikuroi) infecting the plant.( see text for more information).


Which part of the human brain is largest

  • Cerebellum

  • Thalamus

  • Cerebrum

  • Medulla



The cerebrum is the largest part of the human brain, making up about two-thirds of the brain's mass. It has two hemispheres, each of which has four lobes: frontal, parietal, temporal and occipital.


Which element is cause of itai 1/N desh itai disease

  • Hg

  • Cd

  • Pb

  • As



Itai-itai disease was the name given to the mass cadmium poisoning of Toyama Prefecture, Japan, starting around 1912. The term "itai-itai disease" was coined by locals for the severe pains people with the condition felt in the spine and joints.Cadmium poisoning can also cause softening of bones and kidney failure. 


When the other floral parts are arranged at the base of the gynoecium, the flower is called

  • hypogynous flower

  • perigynous flower

  • epigynous flower

  • agynous flower


hypogynous flower

Hypogamus flower, have a superior ovary, attached directly to the receptacle like other floral parts.


Respiratory enzymes are present in the following organelle

  • peroxysome

  • chloroplast

  • mitochondrion

  • lysosome



Mitochondria function during aerobic respiration to produce ATP through oxidative phosphorylation (def). The respiratory enzymes and electron carriers for the electron transport system are located within the inner mitochondria membrane.


Protein coat of virus is known as

  • capsid

  • virion

  • viroid

  • bacterial wall



capsid is the protein shell of a virus. It consists of several oligomeric structural subunits made of protein called protomers. The observable 3-dimensional morphological subunits, which may or may not correspond to individual proteins, are called capsomers. The capsid encloses the genetic material of the virus.


Vascular tissue in higher plants develop from which of the following

  • Procambium 

  • Protoderm

  • Periblem

  • Cortex



The procambium is a meristematic tissue concerned with providing the primary tissues of thevascular system; the cambium proper is the continuous cylinder of meristematic cells responsible for producing the new vascular tissues in mature stems and roots.