Molecular Basis of Inheritance Assertion Reason Based Questions

The following questions consist of two statements, one labelled as Assertion (A) and the other labelled the Reason ®. Examine these two statements carefully and select the most appropriate answer codes.
a) Assertion and reason both are correct and reason is the correct explanation of Assertion.
b) Assertion and reason both are correct and reason is not the correct explanation of Assertion.
c) Assertion is correct but reason is wrong.
d) Both Assertion and Reason are false.

1. Assertion: The RNA molecules are essential for cell function in both prokaryotes and eukaryotes.
   Reason: They play an important role in protein synthesis.
2. Assertion: Rosalind Franklin, the chief contributor to the discovery of DNA’s structure was not awarded the Nobel Prize.
   Reason: She died of cancer in 1958 at the age of 37.
3. Assertion: Regulator is a gene that codes for a repressor protein molecule.
   Reason: This gene is called on/off switch of transcription.
4. Assertion: Adenine cannot pair with cytosine.
   Reason: These nitrogenous bases do not have a perfect match between hydrogen donor and hydrogen acceptor.
5. Assertion: The amount of A, T, G and C in DNA varies from species to species.
   Reason: According to Chargaff, the percentage of adenine is equal to the percentage of cytosine in DNA.
6. Assertion: RNA polymerase I transcribes rRNAs except 5 rRNA.
   Reason: mRNA is synthesized by RNA polymerase II.
7. Assertion: The two strands of DNA are antiparallel.
   Reason: Only antiparallel polynucleotides from a stable double helix.
8. Assertion: DNA replication is Semiconservative.
   Reason: Each replicated DNA molecule consists of an ‘old’ and a ‘new’ strands.
9. Assertion: Messenger RNA encodes the amino acid sequence of a protein.
   Reason: A triplet of nitrogenous bases in mRNA specifying an amino acid is called an anticodon.
10. Assertion: Genetic code is non-overlapping.
    Reason: No single base take part in the formation of more than one codon.
11. Assertion: Transcription is the mode in which DNA passes genetic information to RNA.
    Reason: Transcription takes place in the cytoplasm of eukaryotic cells.
12. Assertion: The operon is a unit of gene expression.
    Reason: Lac operon in E. coli is an inducible control.
13. Assertion: DNA fingerprinting is also known as genetic fingerprinting.
    Reason: It was developed by James Watson, the first director of Human Genome Project.
14. Assertion: A single mRNA strand is capable to produce different polypeptide chains.
    Reason: The mRNA strands has terminator codons.
15. Assertion: Replication and transcription occur in the nucleus but translation occurs in the cytoplasm.
    Reason: mRNA is transferred from the nucleus into the cytoplasm where ribosomes and amino acids are available for protein synthesis.
16. Assertion: DNA code is copied in the synthesis of mRNA.
    Reason: tRNA moves out of nucleus and after attaching or ribosome form the template.
17. Assertion: RNA produced during transcription in Eukaryotic cells cannot be straight away used in photosynthesis.
    Reason: RNA splicing phenomena helps in the removal of exons.
18. Assertion: The hnRNA in humans has exons and introns.
    Reason: The primary transcript produced in eukaryotes is translated without undergoing any modification or processing.
19. Assertion: Sequences of bases in one polynucleotide chain of DNA can determine the sequence of bases in the other chain.
    Reason: In a DNA, amount of adenine equals that of thymine and amount of guanine equals that of cytosine, i.e., A = T and C = G.
20. Assertion: tRNA acts as an adapter molecule.
    Reason: tRNA recognizes codon sequence of mRNA during translation.
21. Assertion: Same tRNA can recognise more than one codons differing only at the third position.
    Reason: The specificity of a codon is particularly determined the first two bases.
22. Assertion: UAA, UAG and uGA terminate protein synthesis.
    Reason: They are not recognised by tRNA.
23. Assertion: Ribosomes attached to endoplasmic reticulum release proteins into lumen of ER.
    Reason: Such proteins are used for formation of hydrolytic enzymes or are modified.
24. Assertion: The two strands of DNA helix have uniform distance between them.
    Reason: A large sized purine is always paired opposite to a smallbsized pyrimidine.
25. Assertion: RNA is liable and easily degradable.
    Reason: The 2′ – OH group present at every nucleotide in RNA is a reactive group.

Answer Sheet

1. A
2. A
3. C
4. A
5. C
6. B
7. A
8. A
9. C
10. A
11. C
12. B
13. C
14. B
15. A
16. C
17. C
18. C
19. B
20. B
21. A
22. A
23. B
24. A
25. A