Bacteria protect restriction sites in their own DNA from being cut by restriction enzymes by ____

a. synthesizing low quantities of restriction enzymes
b. producing restriction enzymes that do not recognize sequences in their own DNA
c. chemically modifying bases within the restriction sites
d. only activating restriction enzymes when foreign DNA is present in the cell
e. inactivating restriction enzymes through phosphorylation


ANSWER: c

Biology & Microbiology

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Using the figure above and the accompanying paragraph, and knowing that the PKG encoded by the foraging gene has recently been associated with the maturation of out-of-nest behavior in honeybees, what would be a logical explanation for this relationship?

As animals mature, they _____. A) require more food; therefore, PKG levels must increase. B) are more likely to forage; therefore, PKG levels must increase. C) respond to pheromones from the queen, which increases PKG levels. D) are able to fly, an activity that is connected to the increase in PKG levels.

Biology & Microbiology

Which of the following is not a cellular function associated with the microtubule cytoskeleton?

A. muscle contraction B. mitosis C. organization of organelles D. movement of cilia or flagella

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Repressor proteins

a. prevent binding of RNA polymerase to DNA. b. cause the DNA regions that contain the operator to twist or loop. c. inactivate operon genes when their products are not required. d. bind to sets of operators. e. do all of these.

Biology & Microbiology

In what respect do hominins differ from all other anthropoids?

A) lack of a tail B) eyes on the front of the face C) bipedal posture D) opposable thumbs

Biology & Microbiology