Molecular Basis of Inheritance Class 12 MCQ:
1. Griffith worked on ………….
c. Frog eggs
Answer : d
Explanation: Griffith used two strains of pneumococcus (Streptococcus pneumoniae) bacteria which infect mice – a type III-S (smooth) which was virulent, and a type II-R (rough) strain which was nonvirulent.
2. The molecular knives of DNA are …………..
Answer: c ( Endonucleases )
3. Translation occurs in the ……………
Answer: b ( Cytoplasm )
Explanation: In a eukaryotic cell, transcription occurs in the nucleus, and translation occurs in the cytoplasm.
4. The enzyme required for transcription is ………………
a. DNA polymerase
b. RNA polymerase
c. Restriction enzyme
Explanation: RNA polymerase is the main transcription enzyme. Transcription begins when RNA polymerase binds to a promoter sequence near the beginning of a gene (directly or through helper proteins).
5. Transcription is the transfer of genetic information from …………..
a. DNA to RNA
b. tRNA to mRNA
c. DNA to mRNA
d. mRNA to tRNA
Answer: DNA to RNA
6. Which of the following is NOT part of protein synthesis?
d. All of these
7. In the RNA molecule, which nitrogen base is found in place of thymine?
8. How many codons are needed to specify three amino acids?
Answer : 3
Explanation: Answer and Explanation: Three codons are needed to specify three amino acids. Codons can be described as messengers that are located on the messenger RNA (mRNA). It is a sequence of three nucleotides that code for one specific amino acid; therefore, every three nucleotides represent one codon
9. Which of the following is NOT an example of an inducible operon?
a. Lactose operon
b. Histidine operon
c. Arabinose operon
d. Tryptophan operon
Answer: Tryptophan operon
Explanation: Explanation: Lactose operon, galactose operon, and maltose operon are examples of inducible operons.
10. Place the following event of translation in the correct sequence
i. Binding of met-tRNA to the start codon.
ii. Covalent bonding between two amino acids.
iii. Binding of the second tRNA.
iv. Joining of small and large ribosome subunits.
A. iii, iv, i, ii
B. i, iv, iii, ii
C. iv, iii, ii, i
D. ii, iii, iv, i