Exam 8: An Introduction to Metabolism

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?

Energy coupling occurs when

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

Which of the following shows the correct changes in thermodynamic properties for a chemical reaction in which amino acids are linked to form a protein?

The following questions are based on the reaction A + B ↔ C + D shown in the figure below. -Which of the following terms best describes the forward reaction in the figure above?

Which term most precisely describes the cellular process of breaking down large molecules into smaller ones?

Use the following figure to answer the question below. Rate of an enzyme-catalyzed reaction as a function of varying reactant concentration,with the concentration of enzyme constant. -For the enzyme-catalyzed reaction shown in the figure,which of these treatments will cause the greatest increase in the rate of the reaction,micromolar?

Which of the following is true for all exergonic reactions?

A number of systems for pumping ions across membranes are powered by ATP.Such ATP-powered pumps are often called ATPases although they don't often hydrolyze ATP unless they are simultaneously transporting ions.Because small increases in calcium ions in the cytosol can trigger a number of different intracellular reactions,cells keep the cytosolic calcium concentration quite low under normal conditions,using ATP-powered calcium pumps.For example,muscle cells transport calcium from the cytosol into the membranous system called the sarcoplasmic reticulum (SR).If a resting muscle cell's cytosol has a free calcium ion concentration of 10⁻⁷ while the concentration in the SR is 10⁻²,then how is the ATPase acting?

HIV is the virus that causes AIDS.In the mid-1990s,researchers discovered an enzyme in HIV called protease.Once the enzyme's structure was known,researchers began looking for drugs that would fit into the active site and block it.If this strategy for stopping HIV infections were successful,it would be an example of what phenomenon?

In experimental tests of enzyme evolution,in which a gene encoding an enzyme is subjected to multiple cycles of random mutagenesis and selection for altered substrate specificity,the resulting enzyme had multiple amino acid changes associated with altered substrate specificity.Where in the enzyme were these amino acid changes located?

Use the following information to answer the questions 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 malonic acid's role with respect to succinate dehydrogenase?