Steroid Hormones

Question 1

steroid hormones are derived from […], a characteristic […] ring structure.

Answer 1

cholesterol
4 ring (A, B, C, D)

Question 2

cholesterol is converted to [….], then progesterone. Progesterone is the basis for all other steroids (testosterone, estradiol, cortisol, aldosterone).

Answer 2

pregnenolone.

Question 3

steroid hormones are formed by [….] cleavage and […] of cholesterol side chains.

Answer 3

side chain

oxidation

Question 4

cholesterol (27 carbon) is converted to pregnenolone (21 carbon) by the enzyme […] through cleavage of a cholesterol side chain.

This is a hydroxylation reaction involving [..3..]

This step is activated by […] and […]

Answer 4

cholesterol desmolase

NADPH, O2, and cytochrome P450

ACTH and Angiotensin II

Question 5

Pregnenolone is converted to progesterone in two steps:

1. they 3-hydroxyl group is oxidized to a […..] group via […..] reaction
2. The alpha-5 double bond is isomerized to an […..] via

Answer 5

3-keto
oxidation of OH group to a keto group reaction.

alpha-5 double bond.
keto/enol tautomerization reaction where c5-c6 double bond moves to c4-c5 position