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NEET - 2021 Previous Year Questions



NEET Biology Previous Year Questions - 2021

During the process of gene amplification using PCR, if very high temperature is not maintained in the beginning, then which of the following steps of PCR will be affected first?

NEET-2021 [Biotechnology-Principles-and-Processes] [class-xii ]

  • Annealing
  • Extension
  • Denaturation
  • Ligation
  • Correct Option: C  [ Denaturation ]

    Remark:

A specific recognition sequence identified by endonucleases to make cuts at specific positions within the DNA is:

NEET-2021 [Biotechnology-Principles-and-Processes] [class-xii ]

  • Degenerate primer sequence
  • Okazaki sequences
  • Palindromic Nucleotide sequences
  • Poly(A) tail sequences
  • Correct Option: C  [ Palindromic Nucleotide sequences ]

    Remark:

With regard to insulin choose correct options.
A. C-peptide is not present in mature insulin.
B. The insulin produced by rDNA technology has C-peptide.
C. The pro-insulin has C-peptide.
D. A-peptide and B-peptide of insulin are interconnected by disulphide bridges.
Choose the correct answer from the options given below.

NEET-2021 [Biotechnology-and-its-Applications] [class-xii ]

  • B and D only
  • B and C only
  • A, C and D only
  • A and D only
  • Correct Option: C  [ A, C and D only ]

    Remark:

For effective treatment of the disease, early diagnosis and understanding its pathophysiology is very important. Which of the following molecular diagnostic techniques is very useful for early detection?

NEET-2021 [Biotechnology-and-its-Applications] [class-xii ]

  • Western Blotting Technique
  • Southern Blotting Technique
  • ELISA Technique
  • Hybridization Technique
  • Correct Option: C  [ ELISA Technique ]

    Remark:

Dobson units are used to measure thickness of:

NEET-2021 [Environmental-Issues] [class-xii ]

  • CFCs
  • Stratosphere
  • Ozone
  • Troposphere
  • Correct Option: C  [ Ozone ]

    Remark:

Identify the types of cell junctions that help to stop the leakage of the substances across a tissue and facilitation of communication with neighbouring cells via rapid transfer of ions and molecules.

NEET-2021 [Structural-Organisation-in-Animals] [class-xi ]

  • Gap junctions and Adhering junctions, respectively.
  • Tight junctions and Gap junctions, respectively.
  • Adhering junctions and Tight junctions, respectively.
  • Adhering junctions and Gap junctions, respectively.
  • Correct Option: B  [ Tight junctions and Gap junctions, respectively. ]

    Remark:

Following are the statements about prostomium of earthworm.
A. It serves as a covering for mouth.
B. It helps to open cracks in the soil into which it can crawl.
C. It is one of the sensory structures.
D. It is the first body segment.
Choose the correct answer from the options given below.

NEET-2021 [Structural-Organisation-in-Animals] [class-xi ]

  • A, B and C are correct
  • A, B and D are correct
  • A, B, C and D are correct
  • B and C are correct
  • Correct Option: A  [ A, B and C are correct ]

    Remark:

Following are the statements with reference to 'lipids'.
A. Lipids having only single bonds are called unsaturated fatty acids.
B. Lecithin is a phospholipid.
C. Trihydroxy propane is glycerol.
D. Palmitic acid has 20 carbon atoms including carboxyl carbon.
E. Arachidonic acid has 16 carbon atoms.
Choose the correct answer from the options given below.

NEET-2021 [Biomolecules] [class-xi ]

  • A and B only
  • C and D only
  • B and C only
  • B and E only
  • Correct Option: C  [ B and C only ]

    Remark:

During muscular contraction which of the following events occur?
A. 'H' zone disappears
B. 'A' band widens
C. 'I' band reduces in width
D. Myosine hydrolyzes ATP, releasing the ADP and Pi
E. Z-lines attached to actins are pulled inwards
Choose the correct answer from the options given below.

NEET-2021 [Locomotion-and-Movement] [class-xi ]

  • A, C, D, E only
  • A, B, C, D only
  • B, C, D, E only
  • B, D, E, A only
  • Correct Option: A  [ A, C, D, E only ]

    Remark:

Match List-I with List-II.

List-I List-II
(A)Scapula (I)Cartilaginous joints
(B)Cranium (II)Flat bone
(C)Sternum (III)Fibrous joints
(D)Vertebral column (IV)Triangular flat bone
Choose the correct answer from the options given below:

NEET-2021 [Locomotion-and-Movement] [class-xi ]

  • A-II, B-III, C-IV, D-I
  • A-IV, B-II, C-III, D-I
  • A-IV, B-III, C-II, D-I
  • A-I, B-III, C-II, D-IV
  • Correct Option: C  [ A-IV, B-III, C-II, D-I ]

    Remark: