Molecular Basis of Inheritance MCQ for NEET

Molecular Basis of Inheritance MCQ with Answers

Here are the most important molecular basis of inheritance MCQ for NEET with answers to prepare for the upcoming NEET exam.

1. The nucleic acid synthesis takes place in:

• a) 3’-5’ direction
• b) 5’-3’ direction
• c) Both ways
• d) Any direction

Answer: b) 5’-3’ direction
Nucleic acid synthesis occurs in the 5′-3′ direction, as new nucleotides are added to the 3′ end of the growing strand.

2. What is the nature of the strands of the DNA duplex?

• a) Anti-parallel and complementary
• b) Identical and complementary
• c) Anti-parallel and non-complementary
• d) Dissimilar and non-complementary

Answer: a) Anti-parallel and complementary
DNA strands run in opposite directions (anti-parallel) and pair with complementary bases.

3. Hershey and Chase’s experiment was based on the principle:

• a) Transformation
• b) Translation
• c) Transduction
• d) Transcription

Answer: c) Transduction
Hershey and Chase used transduction to show that DNA is the genetic material in bacteriophages.

4. AUG stands for:

• a) Alanine
• b) Methionine
• c) N-formyl methionine
• d) Glycine

Answer: b) Methionine
AUG is the start codon and codes for methionine in eukaryotes.

5. The reason behind the anti-parallel strand of DNA is:

• a) Hydrogen bond
• b) Ionic bond
• c) Phosphodiester bond
• d) Disulphide bond

Answer: c) Phosphodiester bond
Phosphodiester bonds link nucleotides and determine the direction of the DNA strands.

6. In a transcription unit, the promoter is located towards:

• a) 5’end of the structural gene
• b) 3’end of the structural gene
• c) 5’end of the template strand
• d) 3’end of the coding strand

Answer: a) 5’end of the structural gene
The promoter is found upstream, near the 5′ end of the structural gene, and initiates transcription.

7. The primer in DNA replication is:

• a) Small ribonucleotide polymer
• b) Helix destabilizing protein
• c) Small deoxyribonucleotide polymer
• d) Enzyme joining nucleotides of new strands

Answer: a) Small ribonucleotide polymer
Primers are short RNA sequences that start DNA synthesis during replication.

8. Genetic information is transferred from nucleus to cytoplasm through:

• a) RNA
• b) Anticodon
• c) DNA
• d) Lysosomes

Answer: a) RNA
mRNA carries genetic information from the nucleus to the cytoplasm for protein synthesis.

9. The enzyme involved in transcription:

• a) DNA Polymerase I
• b) DNA Polymerase III
• c) RNA Polymerase
• d) DNA Polymerase II

Answer: c) RNA Polymerase
RNA polymerase synthesizes RNA from a DNA template during transcription.

10. Non-sense codons participate in:

• a) Releasing t-RNA from polynucleotide chain
• b) Formation of unspecified amino acids
• c) Terminating message of gene-controlled protein synthesis
• d) Conversion of sense DNA into non-sense DNA

Answer: c) Terminating message of gene-controlled protein synthesis
Nonsense codons act as stop signals during translation, terminating protein synthesis.

11. The proofreading enzyme in DNA replication is:

• a) Primase
• b) DNA Polymerase I
• c) Ligase
• d) DNA Polymerase II

Answer: b) DNA Polymerase I
DNA Polymerase I removes RNA primers and corrects errors in the newly synthesized DNA.

12. Select a ribozyme:

• a) Peptidyl transferase
• b) Helicase
• c) Ribonuclease-P
• d) Both (a) and (c)

Answer: d) Both (a) and (c)
Ribozymes are RNA molecules with enzymatic activity, such as peptidyl transferase and ribonuclease-P.

13. Which step does not occur in translation?

• a) Replication
• b) Termination
• c) Elongation
• d) Initiation

Answer: a) Replication
Replication is the process of copying DNA, not a part of translation, which involves protein synthesis.

14. Select the incorrectly matched pairs:

• a) Purines – Nitrogenous bases cytosine, thymine, and uracil
• b) Recombinant DNA – DNA formed by joining the DNA segments from two different sources
• c) rRNA – RNA found in ribosomes
• d) ATP – The energy-carrying compound in the cell

Answer: a) Purines – Nitrogenous bases cytosine, thymine, and uracil
Purines include adenine and guanine, while cytosine, thymine, and uracil are pyrimidines.

15. The energy source for the elongation process is:

• a) Creatine-PO4
• b) GTP
• c) ATP
• d) All of the above

Answer: b) GTP
GTP provides energy for elongation during translation.

16. The anticodon of initiation codon for protein synthesis is:

• a) UUU
• b) AUG
• c) UAC
• d) CAU

Answer: c) UAC
The anticodon UAC pairs with the AUG start codon during protein synthesis.

17. In lac-operon, which protein is not regulated by the repressor?

• a) Galactosidase
• b) Lactose Permease
• c) Tryptophan
• d) Transacetylase

Answer: c) Tryptophan
Tryptophan is not regulated by the lac operon, as it is part of a different operon system.

18. Which enzyme is not produced during lactose catabolism by E. coli?

• a) 𝜷-galactosidase
• b) Lactose Permease
• c) Thiogalactoside transacetylase
• d) Lactose dehydrogenase

Answer: d) Lactose dehydrogenase
Lactose dehydrogenase is not involved in lactose catabolism in E. coli.

19. The eukaryotic replication of DNA is:

• a) Bidirectional with many origins
• b) Unidirectional with many origins
• c) Bidirectional with a single origin
• d) Unidirectional with a single origin

Answer: a) Bidirectional with many origins
Eukaryotic DNA replication is bidirectional and starts at multiple origins of replication.

20. The amino acid coded by 3 codons is:

• a) Proline
• b) Isoleucine
• c) Tryptophan
• d) Serine

Answer: b) Isoleucine
Isoleucine is coded by three codons, while some amino acids are coded by more or fewer codons.

21. Among the following, which one is the start codon?

• a) AUG
• b) UAA
• c) UAG
• d) UGA

Answer: Option (1) is correct.
Explanation: AUG is the start codon that signals the beginning of protein synthesis.

22 When holoenzyme RNA polymerase attaches to a DNA sequence during transcription, the DNA takes on a saddle-like shape. What is this pattern known as?

• a) AAAT
• b)TATA
• c)GGTT
• d)CAAT

Answer: Option (2) is correct.
Explanation: The TATA box is a crucial DNA sequence for initiating transcription.

23. What is the name of the procedure when polypeptides are converted into amino acids?

• a) Reverse transcription
• b) Reverse translation
• c) Transcription
• d) Translation

Answer: Option (4) is correct.
Explanation: Translation is the process where mRNA is decoded to form a polypeptide chain, resulting in proteins.

24. What is the name of the procedure whereby amino acids are activated in the presence of ATP and linked to their corresponding tRNAs?

• a) Charging-up of tRNA
• b) Charging-up of ATP
• c) TRNA amino acetylation
• d) ATP amino acetylation

Answer: Option (1) is correct.
Explanation: Charging-up of tRNA refers to the attachment of amino acids to their corresponding tRNA molecules.

25. The synthesis of proteins is carried out by which of the following cellular organelles?

• a) Lysosomes
• b) Mitochondria
• c) Nucleus
• d) Ribosomes

Answer: Option (4) is correct.
Explanation: Ribosomes are the cellular structures responsible for synthesizing proteins.