SAT Subject Biology Practice Question 10: Answer and Explanation
1. The genetic code table shows the amino acids that correspond to mRNA codons. Each codon is read from 3' (first nucleotide) to 5' (third nucleotide). A DNA template strand is shown. Which amino acid sequence will be assembled from the mRNA associated with this strand?
DNA template strand: 5'-GCG ACA TAC ACT-3'
Correct Answer: B
The DNA template is used to produce a complementary RNA strand with the sequence 3'-CGC UGU AUG UGA-5'. The first three codons specify the amino acids alanine, cystine, and methionine, respectively. The last codon is a stop codon, which tells the ribosome to end translation.