Exam 9: Cellular Respiration and Fermentation

If glucose is the sole energy source, what fraction of the carbon dioxide exhaled by animals is generated only by the reactions involved in oxidation of pyruvate to acetyl CoA?

- The citric acid cycle.Starting with citrate, which of the following combinations of products would result from three acetyl CoA molecules entering the citric acid cycle?

Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?

When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?

The oxygen consumed during cellular respiration is directly involved in which of the following processes or events?

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

What is the oxidising agent in the following reaction? Pyruvate + NADH + H- Lactate + NAD-

Beta oxidation generates substrates for cellular respiration through which of the following processes?

An organism is discovered that thrives in both the presence and absence of oxygen. Interestingly, as oxygen is removed from the organism's environment, the rate of sugar consumption increases while the growth rate decreases. What do these observations suggest about the likely identity of this organism?

In the absence of oxygen, yeast cells can obtain energy by fermentation, which results in the production of which of the following sets of molecules?

The enzyme phosphofructokinase (PFK) catalyses a key step in glycolysis. PFK is inhibited by high levels of which of the following molecules?

Why is glycolysis considered to be one of the first metabolic pathways to have evolved?

Exposing inner mitochondrial membranes to ultrasonic vibrations will disrupt the membranes. However, the fragments will reseal "inside out". The little vesicles that result can still transfer electrons from NADH to oxygen and synthesise ATP. After the disruption, which components involved in oxidative phosphorylation must be present for electron transfer and ATP synthesis to still occur?

- The citric acid cycle. For each mole of glucose (C₆H₁₂O₆) oxidised by cellular respiration, how many moles of CO₂ are released in the citric acid cycle (see the accompanying figure)?

Energy released by the electron transport chain is used to pump H⁺ ions into which location in eukaryotic cells?

What is the oxidising agent in the following reaction? Pyruvate + NADH + H⁺ → Lactate + NAD⁺

The free energy for the oxidation of glucose to CO₂ and water is -686 kcal/mol, and the free energy for the reduction of NAD⁺ to NADH is +53 kcal/mol. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed?

Which of the following metabolic processes take place in the cytosol of a eukaryotic cell?

Why are carbohydrates and fats frequently considered high-energy foods?

Which of the following statements describes what happens to a molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction?