Exam 3: Energy, Catalysis, and Biosynthesis

Enzymes A and B catalyze different reactions, but use the same reactant molecule as a substrate.The graph in Figure 3-74 presents the reaction rates observed when enzyme A and enzyme B are mixed together in a single test tube containing molecule X.What are the V_max and the apparent K_m values for each enzyme under these conditions? How might these values change for enzyme B if it were analyzed in the absence of enzyme A? Explain your answer. (A) x Y X z (B) Figure 3-74

The potential energy stored in high-energy bonds is commonly harnessed when the bonds are split by the addition of __________ in a process called __________.

Although the biochemical study of reaction rates and free energies is important for understanding each biological reaction individually, these studies do not provide an accurate picture of what is happening to reactants and products inside the cell.Why not?

Energy cannot be created or destroyed, but it can be converted into other types of energy.Cells harvest some of the potential energy in the chemical bonds of foodstuffs to generate stored chemical energy in the form of activated carrier molecules, which are often employed to join two molecules together in __________ reactions.

Arrange the following molecules in order with respect to their relative levels of oxidation (assign 5 to the most oxidized and 1 to the most reduced). _______ CH₂O (formaldehyde) _______ CH₄ (methane) _______ CHOOH (formic acid) _______ CH₃OH (methanol) _______ CO₂ (carbon dioxide)

Chemical reactions are reversible; they can proceed in both the forward and reverse directions.If the ΔG° for the reaction Y→X is energetically favorable, how can you explain the fact that not all of the Y molecules will be converted to X molecules?

The net distance a molecule travels through the cytosol via diffusion is relatively short in comparison with the total distance it may need to travel.This is because movement governed by diffusion alone is a __________ process that is most effective for the dispersion of small molecules over short distances.

Unlike what occurs when fuel is burned to make a fire, all living systems use the energy from heat-generating reactions to create and maintain

Fill in the blanks, selecting from the choices below. CO, CO₂, O₂, H₂, H₂O, N₂, NO Light + _________ + _________ → _________ + heat + sugars

During respiration, energy is retrieved from the high-energy bonds found in certain organic molecules.Which of the following, in addition to energy, are the ultimate products of respiration?

Activated carriers store energy in different types of high energy bonds.Match the groups used in high-energy linkages (right column) for each of the of the activated carriers (left column).Each group number may be used more than once. _____ ATP 1.glucose _____ NADH 2.electrons and hydrogens _____ acetyl CoA 3.carboxyl group _____ carboxylated biotin 4.phosphate _____ NADPH 5.methyl group _____ S-adenosylmethionine 6.acetyl group _____ FADH₂ _____ uridine diphosphate

The synthesis of glutamine from glutamic acid requires the production of an activated intermediate followed by a condensation step that completes the process.Both amino acids are shown in Figure 3-47. Figure 3-47 In the condensation step, __________ is displaced by __________.