In total, how many codons are listed in the genetic code?
a. 4
b. 20
c. 36
d. 64
d. 64
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Which of the following does not describe an aspect of the three-dimensional structure of the DNA helix?
A. The deoxyribose has the C-2' endo conformation, which defines the distance between adjacent phosphate groups. B. The hydrophilic backbone of the alternating sugar and phosphate groups is on the outside of the helix. C. The nearly planar and hydrophobic bases are stacked inside the helix relatively perpendicular to the backbone. D. Additional stability is conferred by the hydrogen bonding between the complementary bases. E. All of these choices correctly describe the structure of the DNA helix.
What would be a primary advantage of using an attenuated agent rather than just an antigen from that agent for a vaccine?
A. This is actually a disadvantage-it's much more dangerous to use an attenuated agent over a subunit (single antigen) vaccine due to the possibility of reversion of the microbe to a pathogenic state. B. An attenuated agent strongly stimulates ONLY the antibody production (humoral response) of the adaptive immune system. This provides the best and strongest long-term protection. C. An attenuated agent strongly stimulates ONLY the cytotoxic T cell (CTL, cell-mediated) side of the adaptive immune system. This provides the best and strongest long-term protection. D. An attenuated agent strongly stimulates both the humoral (antibody) AND cell-mediated (T cell) portions of the adaptive immune response, giving the best comprehensive long-term protection available.
Larval salamanders eat small insects and crustaceans. These insects and crustaceans are
herbivores. Thus, the salamanders belong to the __________ trophic level.
a. first b. second c. third d. fourth
The figure shown above is of what kind of tissue?
a. blood b. adipose c. bone d. cartilage e. dense connective