UV light is used to produce vitamin D. Yet, why do people whose ancestors lived in the tropics have darker-colored skin?
A. Darker-colored skin allowed more production of vitamin D.
B. Darker-colored skin protected vitamin D from degradation.
C. Darker-colored skin keeps people warmer.
D. Darker-colored skin was important for social interactions.
E. Darker-colored skin provides protection against cancer-causing UV light.
Answer: E. Darker-colored skin provides protection against cancer-causing UV light.
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Which of the following statements is true about specialized transduction?
A) Specialized transduction occurs in all bacteriophage except the temperate phages. B) A bacteriophage may at some point become reactivated, excise itself and surrounding bacterial genes from the genome, and begin to build new phage particles. C) Specialized transduction requires that bacteriophage infect at least two different cells to be carried out. D) Bacteriophage undergoing specialized transduction integrate their DNA into a random region of the host cell's genome. E) Specialized transduction always directs the production of new phage particles immediately upon infecting the host bacterium.
AMP-activated protein kinase (AMPK) is an enzyme that is activated by high levels of AMP in cells. If levels of AMP are high in cells, that means that levels of ATP are low. Once active, AMPK activates catabolic pathways and inhibits anabolic pathways in the cell. Why do you think that is the case? Choose the answer that best explains the role of AMPK
A. High levels of AMP indicate that there is a high amount of energy stored in the cell, thus activating catabolic pathways and inhibiting anabolic pathways are mechanisms to use stored energy. B. By inhibiting anabolic pathways, AMPK provides a mechanism to generate heat for the cell, which is important if AMP levels are high in the cell. C. By activating catabolic pathways, AMPK provides a mechanism to activate exergonic pathways, which is important if AMP levels are high in the cell. D. Activating catabolic pathways and inhibiting anabolic pathways will ultimately lead to higher consumption of ATP, which is important if AMP levels are high in the cell.
Organisms are composed of molecules, which are collections of smaller units, termed:
A. monomers. B. atoms. C. electrons. D. polymers. E. ions.
Rubisco functions as both a(n) ____ and a(n) ____
a. enzyme; substrate b. enzyme; product c. carboxylase; kinase d. carboxylase; phosphatase e. carboxylase; oxygenase