Lecture 3 Flashcards
Which of the following would be unlikely to contribute to the substrate specificity of an enzyme?
a. A similar shape exists between a pocket on the surface of the enzyme and a functional group on the substrate.
b. The enzyme has an allosteric regulatory site.
c. A hydrophobic group on the substrate interacts with several hydrophobic amino acids on the enzyme.
d. The enzyme has the ability to change its configuration in response to the substrate binding.
A positive charge on the substrate is attracted to a negative charge in the active site of the enzyme.
b. The enzyme has an allosteric regulatory site.
Which of the following is NOT a way in which an enzyme can speed up the reaction that it catalyzes?
a. The enzyme binds a cofactor that interacts with the substrate to facilitate the reaction.
b. The active site can provide heat from the environment that raises the energy content of the substrate.
c. The binding of two substrates in the active site provides the correct orientation for them to react to form a product.
d. The active site of the enzyme can provide a microenvironment with a different pH that facilitates the reaction.
e. Binding of the substrate to the active site can stretch bonds in the substrate that need to be broken.
b. The active site can provide heat from the environment that raises the energy content of the substrate.
Which of the following is true when comparing an uncatalyzed reaction to the same reaction with a catalyst?
a. The catalyzed reaction will have the same G.
b. The catalyzed reaction will consume all of the catalyst.
c. The catalyzed reaction will have higher activation energy.
d. The catalyzed reaction will be slower.
a. The catalyzed reaction will have the same G.
Which temperature and pH profile curves on the graphs were most likely generated from analysis of an enzyme from a human stomach where conditions are strongly acid?
a. curves 2 and 4
b. curves 1 and 4
c. curves 3 and 4
d. curves 1 and 5
(See Lecture 3 Question 4)
b. curves 1 and 4
You have isolated a previously unstudied protein, identified its complete structure in detail, and determined that it catalyzes the breakdown of a large substrate. You notice it has two binding sites. One of these is large, apparently the bonding site for the large substrate; the other is small, possibly a binding site for a regulatory molecule. What do these findings tell you about the mechanism of this protein?
a. It is probably an enzyme that works through allosteric regulation.
b. It is probably a cell membrane transport protein-like an ion channel.
c. It is probably an enzyme that works through competitive inhibition.
d. It is probably a structural protein that is involved in cell-to-cell adhesion.
a. It is probably an enzyme that works through allosteric regulation.
