Final answer:
The claim that normal fetal hemoglobin (HbF) is composed of two alpha (α2) and two gamma (γ2) chains is true. HbF is distinguished from adult hemoglobin (HbA) by the presence of gamma chains instead of beta chains, which facilitates a higher oxygen affinity suitable for the fetus.
Step-by-step explanation:
The student's question relates to the composition of hemoglobin, specifically pertaining to fetal hemoglobin, or HbF. The correct answer is that it is true that normal fetal hemoglobin (HbF) is composed of two alpha (α2) and two gamma (γ2) chains, making the full composition α2γ2. This type of hemoglobin is found in the growing fetus and is essential for carrying oxygen through the fetal bloodstream. In contrast, normal adult hemoglobin (HbA) has two alpha and two beta (β2) chains.
Hemoglobin variations have different affinities for oxygen, with HbF having a higher affinity than the adult form (HbA), which is advantageous for fetal oxygen uptake from the maternal bloodstream. The presence of the gamma chain in place of the beta chain in HbF is what confers this higher oxygen affinity.