Attachment of HIV to the target cell depends on
A) gp120 combining with the CD4+ receptor.
B) gp120 combining with the chemokine receptor CCR5.
C) gp41 binding to the CD4+ receptor.
D) gp120 binding to the CD4+ plasma membrane.
E) CXCR4 binding to the CD4+ receptor.
A
You might also like to view...
All of the petals of a flower are collectively called the
(a) corolla. (b) stamens. (c) receptacles. (d) calyx.
Depurination is a type of mutation where a purine base is lost, but the DNA backbone remains intact. Which of the following are likely to occur as a result of depurination?
A. An incorrect base can be incorporated in the next round of replication. B. A deletion will occur, and there will be an overall loss of a base to the DNA strand. C. Repair enzymes will recognize the error and replace the defective nucleotide. D. All of the above are correct. E. Both a and c are correct.
Which waste products result from the breakdown of proteins in animals?
What will be an ideal response?
The figure below shows phenotypic measures for fossils that have been taxonomically classified as belonging to two different species. Which of the following scenarios are possible explanations for the observed pattern?
a. several extinction events (taxonomic classification underestimates number of species) b. one extinction event (taxonomic classification matches the number of species) c. no extinction event (taxonomic classification overestimates the number of species) d. All of the above