Question

identify structural difference(s) between cholesterol and testosterone.

select all that apply:

cholesterol and testosterone have different groups connected to c - 3 of the a - ring.

cholesterol and testosterone have different groups connected to c - 17 of the d - ring.

cholesterol and testosterone have different groups connected to c - 19 in the a - ring.

the b - ring of cholesterol contains a carbon - carbon double bond between c - 5 and c - 6, whereas the a - ring of testosterone has a carbon - carbon double bond between c - 4 and c - 5.

the a - ring of cholesterol contains a carbon - carbon double bond between c - 4 and c - 5, whereas the b - ring of testosterone has a carbon - carbon double bond between c - 6 and c - 7.

the a - ring of cholesterol contains a carbon - carbon double bond between c - 1 and c - 2, whereas the a - ring of testosterone has a carbon - carbon double bond between c - 2 and c - 3.

Explanation:

• For the first option: In cholesterol, at C - 3 of the A - ring, there is an - OH group. In testosterone, at C - 3 of the A - ring, there is a carbonyl (\(C = O\)) group. So, they have different groups at C - 3 of the A - ring.
• For the second option: Cholesterol has a long hydrocarbon chain attached to C - 17 of the D - ring, while testosterone has a methyl (\(CH_3\)) group attached to C - 17 of the D - ring. So, they have different groups at C - 17 of the D - ring.
• For the fourth option: Looking at the structures, in cholesterol, the B - ring has a \(C = C\) double bond between C - 5 and C - 6. In testosterone, the A - ring has a \(C = C\) double bond between C - 4 and C - 5.

• For the third option: In both cholesterol and testosterone, C - 19 (in the A - ring) has a methyl (\(CH_3\)) group. So, this option is incorrect.
• For the fifth option: In cholesterol, the double bond in the A - ring is not between C - 4 and C - 5 (it's in the B - ring as \(C_5 - C_6\) double bond). In testosterone, the double bond in the A - ring is between C - 4 and C - 5, not in the B - ring. So, this option is incorrect.
• For the sixth option: In cholesterol, the A - ring does not have a \(C_1 - C_2\) double bond. In testosterone, the A - ring has a \(C_4 - C_5\) double bond. So, this option is incorrect.

Answer:

• Cholesterol and testosterone have different groups connected to C−3 of the A - ring.
• Cholesterol and testosterone have different groups connected to C−17 of the D - ring.
• The B - ring of cholesterol contains a carbon - carbon double bond between C−5 and C−6, whereas the A - ring of testosterone has a carbon - carbon double bond between C−4 and C−5.