[Campbell Biology P.551] According to the "Events at the Molecular Level" section and the pr... | Practice Question

According to the "Events at the Molecular Level" section and the provided diagrams, what is the primary molecular cause of sickle-cell hemoglobin's abnormal behavior under low-oxygen conditions?

  • A: A point mutation where an adenine replaces a thymine in the template strand, leading to a valine replacing a glutamic acid, which causes hydrophobic interactions.
  • B: The red blood cell losing its nucleus, which impairs its ability to transport oxygen efficiently.
  • C: An enzyme deficiency that prevents proper oxygen binding to hemoglobin.
  • D: Overproduction of red blood cells, leading to excessive blood viscosity and clotting.

Explanation

The text states that a point mutation adenine replaces thymine leads to an amino acid change valine replaces glutamic acid . This altered amino acid causes hydrophobic interactions between hemoglobin proteins, leading them to bind together and form fibers under low-oxygen conditions.