Problem 4 - AP Psychology Premium Prep 2021

Question

If a messenger RNA codon is UAC, which of the following would be the complementary anticodon triplet in the transfer RNA? (A) ATG (B) \(\mathrm{AUC}\) (C) \(\mathrm{AUG}\) (D) ATT

Step-by-Step Solution

Answer

The complementary anticodon triplet in the transfer RNA for the given messenger RNA codon UAC is (C) \(\mathrm{AUG}\).

Step 1: Understand mRNA and tRNA relationship

Messenger RNA (mRNA) carries genetic information from the DNA to the ribosome, where it is translated into proteins. Each group of three nucleotides, or triplet, in the mRNA sequence is called a codon. Transfer RNA (tRNA) molecules help transfer amino acids to the ribosome during protein synthesis. Each tRNA molecule has a triplet sequence, called the anticodon, which is complementary to its corresponding mRNA codon.

Step 2: Determine the complementary bases

To find the complementary anticodon, we need to identify the complementary bases for each nucleotide in the mRNA codon. In RNA, the base pairings are as follows: - Adenine (A) pairs with Uracil (U) - Cytosine (C) pairs with Guanine (G) - Guanine (G) pairs with Cytosine (C) - Uracil (U) pairs with Adenine (A)

Step 3: Find the complementary anticodon

The given mRNA codon is UAC. Using the base pairings from step 2, we can find the complementary anticodon: - U (Uracil) pairs with A (Adenine) - A (Adenine) pairs with U (Uracil) - C (Cytosine) pairs with G (Guanine) Thus, the complementary anticodon is A-U-G.

Step 4: Match the anticodon with the answer choices

Now we have found the complementary anticodon (AUG), we can match it with the given answer choices: (A) ATG (B) \(\mathrm{AUC}\) (C) \(\mathrm{AUG}\) (D) ATT The correct answer is (C) \(\mathrm{AUG}\).