A second protein, hemoglobin, gives different percent identities than cytochrome c for the same five species. Hemoglobin shows 99 percent (chimp), 86 (mouse), 70 (chicken), 50 (tuna), and 5 (yeast).
Why is cytochrome c more conserved across species than hemoglobin?
- A
Yeast lack DNA, biasing the comparison.
- Bcheck_circle
Cytochrome c performs a fundamental role in respiration shared by nearly all eukaryotes; selection eliminates most variants.
- C
Hemoglobin is not a protein, so it cannot be sequenced.
- D
Hemoglobin evolves before cytochrome c.
Explanation
Highly conserved proteins typically perform essential, ancient functions where most mutations are deleterious; cytochrome c is a core component of the electron transport chain.