Question

which enzyme initiates progesterone synthesis from cholesterol?
aromatase
cyp11a1 (cholesterol side - chain cleavage enzyme)
3β - hsd
orange chickenase

Explanation:

The cholesterol side - chain cleavage enzyme (CYP11A1) initiates the conversion of cholesterol to pregnenolone, which is a precursor in the synthesis of progesterone. Aromatase is involved in estrogen synthesis, 3β - HSD acts later in the progesterone synthesis pathway after pregnenolone formation, and "Orange chickenase" is a non - existent enzyme in biological steroid synthesis.

Answer:

B. CYP11A1 (cholesterol side - chain cleavage enzyme)