Exam 6: An Introduction to Metabolism

The following question(s) are based on the reaction A + B ↔ C + D shown in Figure 6.4. Figure 6.4 -Which of the following best describes the forward reaction in Figure 6.4?

ATP hydrolysis in a test tube releases only about half as much energy as ATP hydrolysis in the cell. Which of the following is the best explanation for this observation?

Figure 6.3 Activity of various enzymes (a) at various temperatures and (b) at various pH. -Which temperature and pH profile curves on the graphs in Figure 6.3 were most likely generated from analysis of an enzyme from a human stomach, where conditions are strongly acid?

Under a particular set of conditions in the lab, the enzyme in a chemical reaction is saturated. Which of the following alterations to the reaction will increase the rate at which substrate is converted to product?

Chemical equilibrium is relatively rare in living cells. Which of the following could be an example of a reaction at chemical equilibrium in a cell?

In experimental tests of enzyme evolution, a gene encoding an enzyme was subjected to multiple cycles of random mutagenesis and selection for altered substrate specificity. The resulting enzyme had altered substrate specificity and multiple amino acid changes. Where in the enzyme would you expect these amino acid changes to be located?

If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to

For the hydrolysis of ATP to ADP + ℗i, the free-energy change is -7.3 kcal/mol under standard conditions (1 M concentration of both reactants and products). In the cellular environment, however, the free-energy change is about -13 kcal/mol. What can we conclude about the free-energy change for the formation of ATP from ADP and ℗i under cellular conditions?

Which of the following metabolic processes can occur without a net influx of energy from some other process?

Some bacteria are metabolically active in hot springs because

Please use the following information to answer the question(s) below. Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid. -What is the role of malonic acid with respect to succinate dehydrogenase?

The induced fit model of enzyme activity suggests which of the following?

A chemical reaction that has a positive ΔG is best described as

Please use the following information to answer the question(s) below. Succinate dehydrogenase catalyzes the conversion of succinate to fumarate. The reaction is inhibited by malonic acid, which resembles succinate but cannot be acted upon by succinate dehydrogenase. Increasing the ratio of succinate to malonic acid reduces the inhibitory effect of malonic acid. -Based on this information, which of the following is correct?

Most cells cannot harness heat to perform work because

Figure 6.1 -Which of the following is the most correct interpretation of Figure 6.1?

Alteration of an amino acid at a site distant from the active site of an enzyme may alter the substrate specificity of the enzyme by

The following question(s) are based on the reaction A + B ↔ C + D shown in Figure 6.4. Figure 6.4 -Which of the following represents the ΔG of the reaction in Figure 6.4?

What is the difference (if any) between the structure of ATP and the structure of the precursor of the A nucleotide in RNA?

Which of the following statements about enzyme-catalyzed reactions is true?