Quiz 9: Cellular Respiration and Fermentation

Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy? The covalent bonds in organic molecules and molecular oxygen have more kinetic energy than the covalent bonds in water and carbon dioxide. Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O). The covalent bond in O2 is unstable and easily broken by electrons from organic molecules. The oxidation of organic compounds can be used to make ATP. The electrons have a higher potential energy when associated with water and CO2 than they do in organic compounds.

Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O).

Which of the following statements describes NAD+? NAD+ has more chemical energy than NADH NAD+ can donate electrons for use in oxidative phosphorylation NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. NAD+ is oxidized by the action of hydogenases In the absence of NAD+, glycolysis can still function

NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.

In cellular respiration, the energy for most ATP synthesis is supplied by transferring electrons from organic molecules to pyruvate a proton gradient across a membrane converting oxygen to ATP high energy phosphate bonds in organic molecules generating carbon dioxide and oxygen in the electron transport chain

a proton gradient across a membrane

The oxygen consumed during cellular respiration is involved directly in which process or event? the citric acid cycle accepting electrons at the end of the electron transport chain the phosphorylation of ADP to form ATP glycolysis the oxidation of pyruvate to acetyl CoA

accepting electrons at the end of the electron transport chain

During aerobic respiration, electrons travel downhill in which sequence? glucose --> ATP --> electron transport chain --> NADH food --> glycolysis --> citric acid cycle --> NADH --> ATP food --> citric acid cycle --> ATP --> NAD+ glucose --> pyruvate --> ATP --> oxygen food --> NADH --> electron transport chain --> oxygen

food --> NADH --> electron transport chain --> oxygen

Which of the following occurs in the cytosol of a eukaryotic cell? oxidative phosphorylation glycolysis and fermentation fermentation and chemiosmosis citric acid cycle oxidation of pyruvate to acetyl CoA

glycolysis and fermentation

The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction loses electrons and loses potential energy gains electrons and gains potential energy loses electrons and gains potential energy neither gains nor loses electrons, but gains or loses potential energy gains electrons and loses potential energy

loses electrons and loses potential energy

Carbon Dioxide (CO2) is released during which of the following stages of cellular respiration? fermentation and glycolysis glycolysis and the oxidation of pyruvate to acetyl CoA oxidation of pyruvate to acetyl CoA and the citric acid cycle the citric acid cycle and oxidative phosphorylation oxidative phosphorylation and fermentation

oxidation of pyruvate to acetyl CoA and the citric acid cycle

One function of both alcohol fermentation and lactic acid fermentation is to oxidize NADH to NAD+ reduce NAD+ to NADH reduce FADH2 to FAD+ reduce FAD+ to FADH2 do none of the above

oxide NADH to NAD+

During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is retained in the two pyruvates used to phosphorylate fructose to form fructose 6-phosphate transferred directly to ATP transferred tp ADP, forming ATP stored in the NADH produced

retained in the two pyruvates