To determine the anticodon of the next tRNA to enter the A site, you must first identify the mRNA codon currently positioned in the A site of the ribosome. The anticodon on the tRNA is always complementary and antiparallel to the mRNA codon. For example, if the codon in the A site is 5'-AUG-3', the tRNA anticodon would be 3'-UAC-5'

. Here's how you determine the anticodon:

• Write the mRNA codon in the 5' to 3' direction.
• The anticodon will be the complementary bases, written in the 3' to 5' direction.

Base pairing rules:

• A (adenine) pairs with U (uracil)
• U (uracil) pairs with A (adenine)
• G (guanine) pairs with C (cytosine)
• C (cytosine) pairs with G (guanine)

Example:

• If the mRNA codon in the A site is 5'-GCA-3', the anticodon on the incoming tRNA would be 3'-CGU-5'

Without the actual figure or the specific codon shown in the A site, you must use the codon provided to determine the anticodon using this complementary base pairing logic. If you provide the mRNA codon in the A site, the exact anticodon sequence can be given.