Explain how a mutant CC-CKR5 allele offers protection from HIV infection. What will be an ideal response?
ANSWER: Normal alleles of the CC-CKR5 gene encode a cell-surface protein that signals the immune
system when an infection is present. HIV binds to this protein and uses it to infect T4 helper
cells. The mutant allele contains a small deletion (32 base pairs) that produces a shorter
protein that HIV cannot use to infect T4 cells. As a result, people who are homozygous for
this CC-CKR5 mutation are resistant to HIV infection.
You might also like to view...
The measure of differential survival and reproductive success is termed _____________________
Fill in the blank(s) with correct word
In this figure, which organ is associated with the breakdown of fat globules?
a. A b. B c. C d. D e. E
Many drugs are produced by placing human genes into bacteria. The bacteria then transcribe and translate these gene into functional human proteins that can then be purified and given as drugs. The fact that this process works is consistent with which hypothesis?
A. Bacteria have evolved to mimic human cells. B. Bacteria cannot divide unless they are inside a host cell. C. Humans and bacteria share a common ancestor. D. Bacteria need to make human proteins to live inside the human body. E. Humans and bacteria use different genetic material.
Which statement best describes the relationship between an enzyme and a reactant?
A) The relationship is temporary. B) The enzyme and the reactant molecule are both permanently changed. C) The resultant product and the enzyme are permanently bonded together. D) Covalent chemical bonds stabilize the relationship. E) One enzyme typically has many reactants with which it will associate.