Question

This table shows the codons found in messenger RNA (attached). Using this information, what sequence of nucleotides in the template strand of DNA could code for the polypeptide sequence Val-His-Thr?
A. GUA-CAU-ACC (THIS IS WRONG)

B. GTA-CAT-ACC

C. CAT-GTA-TGG

D. CAU-GUA-UGG


Please explain, I'm very confused about this topic and I want to learn about it. No false answers or you will immediately be reported. Thanks in advance!

Answer 1

Answer:

A

Explanation:

The correct answer would be option A - GUA-CAU-ACC

Looking at the table of codons, for the amino acid Val, the first base (which is on the 1st column in the 6th row) is G while the second base (2nd column, 2nd row) is U. The third column can be any of U, C, A, or G (6th column, 4th row). Hence, GUA is plausible

For the amino acid His, the first base is C (1st column, 2nd row), the second is A (4th column, 4th row) while the last could be any of the 4 bases. Hence, CAU is plausible.

For the amino acid Thr, the first base is A (first column, 5th row), the second is C (3rd column, 2nd row) while the 3rth could be any of the 4 nucleotide bases. Hence, ACC is plausible.

Therefore, the correct sequence of nucleotides for Val-His_Thr would be GUA-CAU-ACC