In humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. Why is this the case?
A) Nonidentical genes produce different versions of globins during development.
B) Pseudogenes interfere with gene expression in adults.
C) The attachment of methyl groups to cytosine following birth changes the type of hemoglobin produced.
D) Histone proteins change shape during embryonic development.

Question

Quizplus · Accepted Answer

During development, different genes are expressed at different stages, including genes that produce different forms of globins. Embryonic and fetal hemoglobin are composed of different globin gene products than adult hemoglobin, which results in their higher affinity for oxygen.

Answer choices B, C, and D are incorrect. Pseudogenes do not interfere with gene expression in adults, methylation of cytosine does not change the type of hemoglobin produced, and the shape of histone proteins alone does not impact hemoglobin production or affinity for oxygen.

In Humans, the Embryonic and Fetal Forms of Hemoglobin Have