Thyroid hormones T3 and T4 contain which element?

AIron

BIodine (3 atoms in T3, 4 in T4)

CCalcium

DSulfur

Answer & Solution

Correct answer: B. Iodine (3 atoms in T3, 4 in T4)

T3 = triiodothyronine, T4 = thyroxine (tetraiodothyronine). Both contain iodine. Made from tyrosine + iodine in thyroid follicles. T3 more active. Iodine deficiency → goiter, hypothyroidism. Iodized salt prevents deficiency.

Practise this question with Quill — AP Biology →

Keep practising Unit 2G: Osmoregulation & Membrane Dynamics

Browse all Unit 2G: Osmoregulation & Membrane Dynamics questions for AP Biology, or explore more Biology topics.

Start a Unit 2G: Osmoregulation & Membrane Dynamics lesson →

Related questions

Cells that possess a membrane-bound, well-organised nucleus are called:A feature common to prokaryotes and many eukaryotes (e.g. plants, fungi) is Ribosomes are organelles that are:The scientist who first observed and described a living cell was:DNA content at various cell cycle phases (C = haploid DNA content):Number of bivalents (paired homolog pairs) at metaphase I of a cell with 2n = 12:Estrogen and progesterone, secreted mainly by ovaries during reproductive cycle, are:Cortisol secretion peaks in the: