Infection with HIV (human immunodeficiency virus) typically _____
A) increases the level of helper T cells for the first year after infection
B) eliminates all T cells immediately
C) leads to an immediate decrease in the number of HIV in the blood
D) alters mitochondrial but not genomic DNA sequences
E) is found in B cells but not in T cells
Answer: A
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Fluzone is a brand name for a very commonly given influenza vaccine. The vaccine is prepared by first harvesting flu viruses in chicken embryos and then breaking apart virus particles into protein subunits, thereby inactivating the virus. Your friend refuses to get the vaccine. Which of these statements is the only valid reason for her not to get the flu vaccine?
A. She could die from the vaccine. B. She could pass the virus onto her baby, causing the child to become autistic. C. She could catch the flu from the inactivated vaccine. D. She is allergic to eggs.
Animal cells are permeable to water and urea but NOT to sucrose. Initially, the inside of a cell contains 1 M sucrose and 1 M urea and the outside 2 M sucrose and 1 M urea. After the system reaches equilibrium, what changes are observed?
A. The molarity of urea would be higher outside than inside the cell. B. The molarity of sucrose would be similar inside and outside the cell. C. Water would move out of the cell causing the cell to shrivel. D. The molarity of urea would be higher outside the cell and the molarity of sucrose would be similar inside and outside the cell. E. The molarity of sucrose would be similar inside and outside the cell and water would move out of the cell causing the cell to shrivel.
Mitosis and cytoplasmic division function in
a. growth. b. repair of damaged tissue. c. replacement of worn-out cells. d. asexual reproduction. e. all of these.
Which of the following is NOT used or related
to the creation of recombinant DNA?
a. ligases b. restiction enzymes c. plasmids d. SNPs e. sticky ends