Question

Regarding the assertion and reason, select the correct option.
Assertion $\left[A\right]$: There are only about 40 tRNA molecules for the 61 coding codons.
Reason $\left[R\right]$: The third base of the codon/anticodon have some unconventional base pairing.

• A. Both A and R are true and R explains A
• B. Both A and R are true, but R does not explain A
• C. A is true and R is false
• D. Both A and R are false

Answer 1

The correct option is A Both A and R are true and R explains A

The Wobble Hypothesis, proposed by Francis Crick, states that there is some unconventional base pairing between the third nucleotide of the codon-anticodon pair. This means that even if only the first two bases of the codon-anticodon pair are complementary to each other, while the third nucleotides have paired wrongly, the tRNA can still be seated on the correct codon on the mRNA. This explains why there are only around 40 tRNA molecules corresponding to the 61 codons/anticodons.