Cellular Respiration

What fraction of the carbon dioxide exhaled by animals is generated by the reactions of the citric acid cycle, if glucose is the sole energy source?

2/3

For each mole of glucose (C6H12O6) oxidized by cellular respiration, how many moles of CO2 are released in the citric acid cycle (see figure 9.2)

4

Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes. However, the fragments will reseal "inside out." These little vesicles that result can still transfer electrons from NADH to oxygen and synthesize ATP. If the membranes are agitated further, however, the ability to synthesize ATP is lost. After the further agitation of the membrane vesicles, what must be lost from the membrane?

ATP synthase, in whole or in part

If pyruvate oxidation is blocked, what will happen to the levels of oxaloacetate and Citric acid in the citric acid cycle shown in figure 9.2?

Oxaloacetate will accumulate and citric acid will decrease.

Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO2) from one molecule of pyruvate?

acetyl CoA

After the disruption, when electron transfer and ATP synthesis still occur, what must be present?

all of the electron transport proteins as well as ATP synthase

Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in

all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors.

Which kind of metabolic poison would most directly interfere with glycolysis?

an agent that closely mimics the structure of glucose but is not metabolized

Yeast cells that have defective mitochondria incapable of respiration will be able to grow by catabolizing which of the following carbon sources for energy?

glucose

Which catabolic processes may have been used by cells on ancient Earth before free oxygen became available?

glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation, using an electron acceptor other than oxygen

Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount of ATP in a cell would be expected to

inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle.

An organism is discovered that thrives both in the presence and absence of oxygen in the air. Curiously, the consumption of sugar increases as oxygen is removed from the organism's environment, even though the organism does not gain much weight. This organism

is a facultative anaerobe

It is possible to prepare vesicles from portions of the inner mitochondrial membrane. Which one of the following processes could still be carried on by this isolated inner membrane?

oxidative phosphorylation

One function of both alcohol fermentation and lactic acid fermentation is to

oxidize NADH to NAD+

The ATP made during glycolysis is generated by

substrate-level phosphorylation