Which of These Biochemical Events Does NOT Take Place During

Question

Which of these biochemical events does NOT take place during thyroid hormone synthesis
A)one monoiodotyrosine molecule combining with one diiodotyrosine molecule to form one triiodothyronine molecule
B)two iodine molecules combining with one tyrosine molecule to form one diiodotyrosine molecule
C)two diiodotyrosine molecules combining to form one molecule of thyroxine
D)four iodine molecules combining with one tyrosine molecule to form one tetraiodothyronine molecule

Accepted Answer

The synthesis of thyroid hormones does not involve the direct combination of four iodine molecules with one tyrosine molecule to form tetraiodothyronine (thyroxine or T4). Instead, the process involves iodination of tyrosine residues on thyroglobulin (to form monoiodotyrosine and diiodotyrosine), followed by coupling reactions that produce T3 and T4.