In the mechanism of stomatal opening, after light activates proton pumps which of the following
happens next?
a. Guard cells change shape.
b. Hydrogen ions are actively transported out of guard cells.
c. Potassium ions diffuse into guard cells.
d. Chloride ions diffuse out of guard cells.
e. Water moves by osmosis into guard cells.
B
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Microtubules are assembled from ____
a. keratin b. myosin
c. laminin d. actin e. tubulin
Amylase is an enzyme that breaks down starch. Why can't the same enzyme break down cellulose?
A. The enzyme cannot attack cellulose because of its helical shape. B. Cellulose molecules are much too large. C. Starch is made of glucose; cellulose is made of fructose. D. The bonds between the monosaccharide monomers in cellulose are much stronger. E. The monosaccharide monomers in cellulose are bonded together differently than in starch.
In one butterfly species, the colors of individuals range from white to black, with many shades of gray in between
If the butterflies in a mountain population become more and more similar in color over several generations (e.g., if most butterflies are the same shade of gray), what kind of evolutionary force is likely acting on the population? A) Artificial selection B) Stabilizing selection C) Directional selection D) Disruptive selection
One way in which an enzyme can lower the activation energy required for a reaction is to bind the substrate(s) and distort its structure so that the substrate more closely resembles the transition state of the reaction
This mechanism will be facilitated if the shape and chemical properties of the enzyme's active site are more complementary to the transition state than to the undistorted substrate; in other words, if the enzyme were to have a higher affinity for the transition state than for the substrate. Knowing this, your friend looked in an organic chemistry textbook to identify a stable chemical that closely resembles the transition state of a reaction that converts X into Y. She generated an antibody against this transition-state analog and mixed the antibody with chemical X. What do you think might happen?