disulfide bond breakage question.Could you help me understand why Option A is considered correct?

Dana_Azzouka
Dana_Azzouka Posts: 6

MCAT Student

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edited January 13 in MCAT Question of the Day

I wanted to ask for clarification on the disulfide bond breakage question.

The question specifically asks about the "breakage of a disulfide bond" and refers to the reduction of S-S to form two S-H groups.

In this context, it seems that Option C clearly shows the breakage of the S-S bond into two thiol groups (S-H), which aligns with the definition of reduction and disulfide bond cleavage. However, the provided answer is Option A, which appears to involve a rearrangement into a cyclic product rather than forming two distinct S-H groups.

Could you help me understand why Option A is considered correct over Option C, especially since the term "breakage" suggests the bond splits into two separate thiol groups?

Best Answer

  • Ae-Ri
    Ae-Ri Posts: 225

    Moderator

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    Answer ✓

    Hi Dana

    This is a tricky question for rephrasing! While you're right, (C ) does show a disulfide bond breaking, the question is asking what would accompany that bond breaking. In other words, since disulfide bond breaking is a reduction reaction, it must mean that this is coupled to an oxidation reaction. Only (A) shows the proper number of electrons being released to break a disulfide bond. Does that help?

Answers

  • Ae-Ri
    Ae-Ri Posts: 225

    Moderator

    🚨
    Answer ✓

    Hi Dana

    This is a tricky question for rephrasing! While you're right, (C ) does show a disulfide bond breaking, the question is asking what would accompany that bond breaking. In other words, since disulfide bond breaking is a reduction reaction, it must mean that this is coupled to an oxidation reaction. Only (A) shows the proper number of electrons being released to break a disulfide bond. Does that help?