How Do Amino Acids Like Hydroxylysine and Thyroxine, Which Are

question 32

Multiple Choice

How do amino acids like hydroxylysine and thyroxine, which are not among the 20 amino acids inserted into amino acid chains, get into proteins?

• A)They are inserted due to mutations.
• B)They are the result of the alteration of R groups of the 20 amino acids after their incorporation into the polypeptide.
• C)They occur as carboxyl groups are altered, reversing the chirality of the molecules.
• D)Insertion of the amino acid into the polypeptide causes bonds to break and new amino acids to form.

---

Definitions:

Archaeplastids

A group in the eukaryotic tree of life that includes red algae, green algae, and land plants, characterized by the presence of plastids with a double membrane.

Antheridium

(pl., antheridia) In plants, the multicellular male gametangium (sex organ) that produces sperm cells. Compare with archegonium.

Archegonium

A female reproductive structure found in ferns, mosses, and some conifers and flowering plants, producing a single egg cell for fertilization.

Sporangium

A spore case, found in plants, certain protists, and fungi.