NEET Class 12

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 Multiple Choice QuestionsMultiple Choice Questions


The molecular structure of insulin was first described by :

  • Korenberg

  • Swaminathan

  • Richardson

  • Sanger



Insulin is a protein of 51 amino acids. It is a peptide hormone, made up of two polypeptide chains joined together by disulphide bridges. It is produced by the beta cells of the pancreatic islets. Sanger was the first person to complete the amino acid sequence of insulin.


Tetradynamous stamens are found in :

  • Chrysanthemum

  • Zinnia

  • Poppy

  • Brassica



Tetradynamous condition of stamens is found in mustard (Brassica campestris) plant of Family- Cruciferae (Brassicaceae). In tetradynamous condition, there are six stamens, four stamens remain long and two short.


When a tall plant with rounded seeds (TTRR) is crossed with a dwarf plant with wrinkled seeds (ttrr), the F1 generation consists of tall plants with rounded seeds. How many types of gametes an F1 plant would produce ?

  • One

  • Three

  • Four

  • Eight



Parent generation - Tall round seeds           Dwarf wrinkled seeds

                                 TTRR                x              ttrr

Gametes              -         TR                                tr

F1 generation        -                     TtRr

Therefore, only one type of gametes is produced in F1 plants, i.e. TtRr or Tall round seeds.


Which of the following pair is characterised by swollen lips, thick pigmented skin of hands and legs and irritability ?

  • Iodine - Goitre

  • Protein - Kwashiorkor

  • Thiamine - Beri-beri

  • Nicotinamide- Pellagra


Nicotinamide- Pellagra

Pellagra is a disease caused by the deficiency of nicotinamide or nicotinic acid or niacin or vitamin B3. It is common among individuals eating food with low tryptophan. The symptoms of pellagra are inflammation of skin or Dermatitis, diarrhoea and dementia.


Insect resistance transgenic cotton has been produced by inserting a piece of DNA from:

  • an insect

  • a bacterium

  • a wild relative of cotton

  • a virus


a bacterium

Insect (i.e., Bollwarm) resistant transgenic cotton has been produced through genetic engineering by inserting a piece of DNA from bacterium Bacillus thuringensis.


Which organism was used by Beadle and Tatum to proposed one gene-one enzyme hypothesis ?

  • E. coli

  • Nostoc

  • Drosophila

  • Neurospora



G.W. Beadle and E.L. Tatum demonstrated by the biochemical mutation experiment in Neurospora that genes express themselves through synthesis of enzymes. They proposed a concept called "one gene-one enzyme hypothesis".


Human immuno deficiency virus causes

  • Acquired immuno deficiency syndrome

  • Anthrax

  • Tuberculosis

  • Polio


Acquired immuno deficiency syndrome

AIDS or Acquired Immuno Deficiency Virus is caused by HIV. It is a chronic, life threatning condition caused by HIV.


Mutations which alter nucleotide sequence within a gene are :

  • frame shift mutations

  • base pair substitutions

  • both 'a' and 'b'

  • none of these


frame shift mutations

Gene mutation or point mutation is the result of a change in the nucleotide sequence of the DNA molecule in a particular region of the chromosome. It occurs in the form of duplication, insertion, deletion, inversion or substitution of bases. Frame- shift mutation is the addition or deletion of a base that may change the reading frame of nucleotide sequence. 

Base pair substitution is a type of mutation involving replacement or substitution of a single nucleotide base with another in DNA or RNA molecule.


Diadelphous stamens are the characteristic features of :

  • Ranunculaceae

  • Fabaceae

  • Poaceae

  • Malvaceae



In diadelphous condition, stamens are arranged in two bundles. Diadelphous stamens are the characteristic features of Family- Fabaceae.


Phytochrome occurs in two forms. In which form it promotes the germination of seeds of some species ?

  • Pfr forms

  • Pr forms

  • Both forms

  • None of these


Pfr forms

Pfr form of phytochrome refers to physiologically active form whereas Pr form refers to inactive form. 

Red light formation means the formation of Pfr. It helps in the induction of seed germination. On the contrary, far red light or Pr formation inhibits the germination.