What is the importance of the pigment melanin in humans?
a. It prevents destruction of vitamin D caused by UV light.
b. It allows formation of vitamin B caused by UV light.
c. It prevents DNA damage by absorbing UV light.
d. It prevents DNA damage by reflecting UV light.
Ans: c. It prevents DNA damage by absorbing UV light.
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During the growing season, when there is often 24 hours of daylight, plants and lichen cover the ground in which of the biomes?
a. boreal forest b. chaparral c. arctic tundra d. temperate grasslands
Concerning HIV, which of these statements is false?
A) HIV is a retrovirus. B) HIV can be cured today. C) HIV must interact with a receptor on the host to infect it. D) HIV utilizes the enzyme reverse transcriptase to copy its RNA to DNA.
Kinetochores attach
A) sister chromatids to each other. B) chromatids to spindle microtubules. C) chromosomes to each other. D) chromosomes to ribosomes.
You have developed a promising anti cancer agent, but it has poor solubility in water. Which of the following changes should improve water solubility?
A.) adding a methyl group B.) increasing the size of the drug C.) adding a hydroxyl group D.) adding a carboxyl group