Cholesterol Synthesis Steps

Question 1

Stage 1

Answer 1

two molecules of acetyl-CoA are condensed and then HMG-CoA reductase (rate-limiting step of the pathway) adds another acetyl-CoA to form 6 C mevalonate

Question 2

Stage 2

Answer 2

ATP donates 2 phosphoryl groups to mevalonate in two separate reactions and isoprene units are involved to form isopentenyl diphosphate/ demethylallyl diphosphate (5 carbons total)

Question 3

Stage 3a

Answer 3

isopentenyl diphosphate is converted to farnesyl diphosphate (15 C)

Question 4

Stage 3b

Answer 4

two farnesyl diphosphate converted to squalene (30 C)

Question 5

Stage 4

Answer 5

squalene is cyclized to form lanosterol, which is converted to cholesterol (27 C) in 19 steps