| Scientist | Contribution |
| Har Gobind Khorana | Developed chemical methods for synthesizing RNA with defined base sequences. |
| Marshall Nirenberg | Developed a cell-free system for protein synthesis that helped in decoding the genetic code. |
| Severo Ochoa | Proved that DNA, not proteins, is the genetic material. |
| 1. | The codon is triplet |
| 2. | The code is nearly universal |
| 3. | The code has punctuations |
| 4. | Some amino acids are coded by more than one codon, hence the code is degenerate |
Which one of the following pairs of codons is correctly matched with their function or the signal for the
particular amino acid ?
1. AUG, ACG – start/methionine
2. UUA, UCA – Leucine
3. GUU – Alanine
4. UAG, UGA – stop
What is not true for genetic code?
1. A codon in mRNA is read in non-contiguous fashion
2. It is nearly universal
3. It is degenerate
4. It is unambiguous
| Assertion(A): | The genetic code is degenerate. |
| Reason(R): | Most amino acids are coded by more than one codon. |
| 1. | Both (A) and (R) are True and (R) is correct explanation of (A) |
| 2. | Both (A) and (R) are True and (R) is not correct explanation of (A) |
| 3. | (A) is True but (R) is False |
| 4. | Both (A) and (R) are False |
| mRNA codon | Amino acid | |
| 1. | AUG | Methionine |
| 2. | GGG | Glycine |
| 3. | UGA | Tryptophan |
| 4. | UAG | None; it is a stop codon |