Which, if any, of the following is NOT true about allosteric proteins?
A. they are sensitive to environmental conditions
B. they exist in active and inactive conformations
C. they are acted on by inhibitors
D. they can bind to a range of substrates
E. all of the following statements are true of allosteric proteins
In general, the hydrolysis of ATP drives cellular work by _________________.
A. changing to ADP and phosphate
B. lowering the free energy of the reaction
C. releasing free energy that can be coupled to other reactions
D. releasing heat
E. acting as a catalyst
Question 3 1 points Save
The mechanism of enzyme action is _______________.
A. lowering the free energy change of a reaction
B. providing energy to speed up the rate of the reaction
C. changing the direction of thermodynamic equilibrium
D. lowering the energy of activation for a reaction
E. changing endergonic into exergonic reactions
Question 4 1 points Save
An exergonic (spontaneous) reaction is a chemical reaction that _____________________.
A. cannot occur outside of a living cell
B. is common in anabolic pathways
C. occurs only when an enzyme or other catalyst is present
D. leads to a decrease in the entropy of the universe
E. releases energy when proceeding in the forward direction
Question 5 1 points Save
Which of the following statements about enzymes is TRUE?
A. Enzymes react with their substrate (form chemical bonds) forming an enzyme-substrate complex, which irreversibly alters the enzyme.
B. The most efficient enzymes can catalyze reactions in either direction.
C. The more heat that is added to a reaction, the faster the enzymes will function.
D. Enzymes speed up the rate of the reaction without changing the free energy for the reaction.
E. Enzymes increase the rate of a reaction by raising the activation energy for reactions.
Question 6 1 points Save
Which is the most abundant form of energy in a cell?
A. heat
B. mechanical energy
C. chemical and electrical gradients
D. chemical energy
E. kinetic energy
Question 7 1 points Save
Consider the growth of a farmer's crop over a season. Which of the following correctly states a limitation imposed by the first or second law of thermodynamics?
A. Growth of crops must occur spontaneously.
B. The entropy of the universe must decrease in order to account for the increase entropy associated with plant growth.
C. The process of photosynthesis produces energy that the plant uses to grow.
D. In order to obey the first law, the crop must represent an open system.
E. All of the above are correct.
Question 8 1 points Save
Which of the following correctly states the relationship between anabolic and catabolic pathways?
A. Degradation of organic molecules by anabolic pathways provides the energy to drive catabolic pathways.
B. The flow of energy between catabolic and anabolic pathways is reversible.
C. Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways.
D. Catabolic pathways produce usable cellular energy by synthesizing more complex organic molecules.
E. Energy derived from catabolic pathways is used to drive the breakdown of organic molecules in anabolic pathways.
Question 9 1 points Save
According to the second law of thermodynamics, which of the following is true?
A. The entropy of the universe is constantly decreasing.
B. The decrease in entropy associated with life must be compensated for by an increase in entropy in the environment that life occurs in.
C. The total amount of energy is the universe is constant.
D. All reactions produce some heat.
E. Energy conversions increase the order in the universe.
Question 10 1 points Save
Above a certain substrate concentration, the rate of an enzyme-catalyzed raction drops as the enzymes become saturated. Which of the following would lead to a faster conversion of substrate into product under these saturated conditions?
A. increasing the temperature by a few degrees
B. an increase in concentration of enzymes
C. increasing the substrate concentration
D. the first and second choices are correct
E. the first, second, and third choices are correct
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