Return to Blog Homepage

MCAT Biology Question — Fetal Hemoglobin

  • by John
  • Sep 26, 2017
  • MCAT Question of the Day

An individual is born with a mutation causing her to partially retain a form of fetal hemoglobin into adulthood. Compared to a normal individual, this person would exhibit:

 

A. no differences from a normal adult.
B. significantly reduced oxygen binding in the lungs.
C. no symptoms, since retention of fetal hemoglobin would be fatal.
D. increased oxygen binding to hemoglobin in the tissues.

Click for Explanation
Fetal hemoglobin has a higher affinity for oxygen than does adult hemoglobin. Thus, it binds and holds oxygen more tightly. An individual with fetal hemoglobin would show increased oxygen binding to hemoglobin as a result. (A) is false because fetal and adult hemoglobin are different. (B) is false because fetal hemoglobin binds more to oxygen, not less. And (C) is false – in fact, reactivating fetal hemoglobin can be used as a treatment for sickle-cell. Therefore, the answer is (D).

Want more MCAT practice?

We’ve got options for every schedule and learning style!

From the best online MCAT course created by top instructors with 524+ MCAT scores to the most representative full-length practice exams and private tutoring, we can custom tailor your MCAT prep to your goals!

Not sure which option is right for you? Schedule a free MCAT consultation with an MCAT expert using the form below. No obligation, just expert advice.

Submit a Comment