Molecular Basis of Inheritance NEET Questions – NEET 2024

The molecular basis of inheritance refers to the way genetic information is transmitted from one generation to the next through the chemical structure of DNA. DNA is made up of four chemical bases: adenine, guanine, cytosine, and thymine. These bases pair up in a specific sequence to form the rungs of a DNA ladder. This sequence of bases determines the genetic code, which is responsible for the inheritance of traits. The process of DNA replication ensures that the genetic information is accurately copied and passed down to the next generation. 

Here are some MCQs related to the molecular basis of inheritance for the NEET exam:

1. Which of the following is not a component of a nucleotide?

a. Nitrogenous base

b. Phosphate group

c. Ribose sugar

d. Deoxyribose sugar

Answer: d. Deoxyribose sugar

2. Which of the following nitrogenous bases is found only in RNA?

a. Adenine

b. Thymine

c. Uracil

d. Guanine

Answer: c. Uracil

3. The shape of DNA molecule is:

a. linear

b. circular

c. helical

d. none of the above

Answer: c. helical

4. In DNA, which of the following nitrogenous bases pairs with adenine?

a. Thymine

b. Cytosine

c. Guanine

d. Uracil

Answer: a. Thymine

5. The process of DNA replication is semi-conservative because:

a. The two resulting DNA molecules are identical

b. Each resulting DNA molecule contains one strand from the original DNA molecule

c. The process involves the creation of new DNA strands from scratch

d. None of the above

Answer: b. Each resulting DNA molecule contains one strand from the original DNA molecule

6. The genetic code is composed of:

a. 2 letters

b. 3 letters

c. 4 letters

d. 5 letters

Answer: b. 3 letters

7. Which of the following is an example of a point mutation?

a. Deletion of a single nucleotide

b. Addition of a single nucleotide

c. Substitution of a single nucleotide

d. All of the above

Answer: d. All of the above

8. Which of the following is not involved in the process of transcription?

a. RNA polymerase

b. DNA polymerase

c. Promoter region

d. Terminator region

Answer: b. DNA polymerase

9. Which of the following is not a type of RNA?

a. Messenger RNA (mRNA)

b. Transfer RNA (tRNA)

c. Ribosomal RNA (rRNA)

d. Deoxyribonucleic acid (DNA)

Answer: d. Deoxyribonucleic acid (DNA)

10. Which of the following is the function of tRNA?

a. To carry amino acids to the ribosome for protein synthesis

b. To transcribe DNA into RNA

c. To carry the genetic code from the nucleus to the cytoplasm

d. None of the above

Answer: a. To carry amino acids to the ribosome for protein synthesis.

11. Which scientist(s) conducted the Hershey-Chase experiment that confirmed DNA as the genetic material?

1. A) Alfred Hershey and Martha Chase
2. B) Frederick Griffith
3. C) Oswald Avery, Colin MacLeod, and Maclyn McCarty
4. D) James Watson and Francis Crick

Answer: A) Alfred Hershey and Martha Chase

12. The basic building blocks of DNA are:

1. A) Amino acids
2. B) Nucleotides
3. C) Fatty acids
4. D) Monosaccharides

Answer: B) Nucleotides

13. DNA replication takes place during which phase of the cell cycle?

1. A) Interphase
2. B) Prophase
3. C) Metaphase
4. D) Anaphase

Answer: A) Interphase

14. The process of converting DNA into RNA is called:

1. A) Transcription
2. B) Translation
3. C) Replication
4. D) Transformation

Answer: A) Transcription

15. Which enzyme is responsible for joining Okazaki fragments during DNA replication in the lagging strand?

1. A) DNA ligase
2. B) DNA polymerase III
3. C) DNA helicase
4. D) DNA polymerase I

Answer: A) DNA ligase

16. The genetic disorder caused by the absence of an enzyme involved in DNA repair is:

1. A) Cystic fibrosis
2. B) Hemophilia
3. C) Xeroderma pigmentosum
4. D) Down syndrome

Answer: C) Xeroderma pigmentosum

17. In RNA, the nitrogenous base uracil (U) replaces thymine (T) found in DNA. True or False?

1. A) True
2. B) False

Answer: A) True

18. Which genetic disorder results from a point mutation, causing the substitution of valine for glutamic acid in the hemoglobin protein?

1. A) Cystic fibrosis
2. B) Sickle cell anemia
3. C) Huntington’s disease
4. D) Down syndrome

Answer: B) Sickle cell anemia

19. The genetic code is degenerate, meaning:

1. A) Each amino acid has only one codon.
2. B) Each codon codes for multiple amino acids.
3. C) Multiple codons can code for the same amino acid.
4. D) The genetic code is constantly changing.

Answer: C) Multiple codons can code for the same amino acid.

20. The region of DNA where RNA polymerase binds to initiate transcription is called:

1. A) Promoter
2. B) Exon
3. C) Intron
4. D) Enhancer

Answer: A) Promoter

21. Which of the following is NOT a nitrogenous base found in DNA?

1. A) Adenine (A)
2. B) Thymine (T)
3. C) Uracil (U)
4. D) Guanine (G)

Answer: C) Uracil (U)

22. In DNA replication, the enzyme responsible for adding new nucleotides to the growing DNA strand is:

1. A) DNA ligase
2. B) DNA polymerase
3. C) RNA polymerase
4. D) Helicase

Answer: b) DNA polymerase

23. Which of the following correctly describes the structure of a DNA molecule?

1. A) Single-stranded helix
2. B) Double-stranded helix
3. C) Triple-stranded helix
4. D) Quadruple-stranded helix

Answer: b) Double-stranded helix

24. The process of converting the genetic information from DNA into a complementary RNA sequence is called:

1. A) Translation
2. B) Replication
3. C) Transcription
4. D) Mutation

Answer: c) Transcription

25. Which of the following genetic disorders is caused by the absence of an enzyme responsible for breaking down phenylalanine?

1. A) Cystic fibrosis
2. B) Hemophilia
3. C) Tay-Sachs disease
4. D) Phenylketonuria (PKU)

Answer: d) Phenylketonuria (PKU)