Question

Synthesis takes place on thyroglobulin molec. within colloid. To make T3 you need ___ & ___. To make T4 you need ___

Answer 1

To produce T3, iodine and one diiodotyrosine plus one monoiodotyrosine are needed, while T4 synthesis requires iodine and two diiodotyrosine molecules. These components are assembled within the protein thyroglobulin in the thyroid follicle cells.

Step-by-step explanation:

To make T3, you need iodine and a tyrosine residue with three iodine atoms attached. To make T4, you need iodine and a tyrosine residue with four iodine atoms attached. Here is the step-by-step synthesis process:

• Iodide ions from the diet are actively transported into follicle cells of the thyroid gland.
• The iodide ions are then oxidized to iodine in the lumen of the follicle cells.
• Iodine is attached to tyrosine residues in the protein thyroglobulin within the follicular colloid. One tyrosine with one iodine atom (monoiodotyrosine) and another with two iodine atoms (diiodotyrosine) are formed.
• For T3 synthesis, one monoiodotyrosine pairs with one diiodotyrosine (totaling three iodine atoms).
• For T4 synthesis, two diiodotyrosine molecules pair together (totaling four iodine atoms).
• Upon stimulation by thyroid-stimulating hormone (TSH), thyroglobulin is broken down, freeing T3 and T4, which then enter the bloodstream.

In summary, the main ingredients required are iodide ions and tyrosine residues within the protein thyroglobulin, in addition to enzymes like thyroperoxidase that aid the synthesis.