Metabolic Pathways and Energy Yield

Which of the following coenzymes will accept two electrons and two hydrogen ions during the oxidation of glucose?

• FADH

• NAD+

• FAD

• NADH

The correct sequence for aerobic metabolic breakdown of glucose is

• glycolysis- preparatory reaction- citric acid cycle- electron transport system.

• preparatory reaction- glycolysis- electron transport- citric acid cycle.

• electron transport system- citric acid cycle- preparatory reaction- glycolysis.

• none of the choices are correct

complete oxidative breakdown of glucose results in____ATP molecules.

• 24-26

• 14-16

• 40=42

• 4-6

• 36-38

during glycolysis ___ carbons will enter the pathway and ____ carbons will leave in the form of pyruvates.

• 3; 6

• 6; 6

• 6; 3

• oxaloacetate

• 12; 6

What is the correct summary for the energy investment vs. energy harvesting steps of glycolysis?

• 4 ATP are invested and 6 ATP are harvested to produce a net gain of 2 ATP.

• 2 ATP are invested and 4 ATP are harvested to produce a net gain of 2 ATP.

• 2 ATP are invested and no ATP are harvested to produce a net loss of 2 ATP.

• No ATP are invested and 2 ATP are harvested to produce a net gain of 2 ATP.

Some bacteria are strict aerobes and others are strict anaerobes. Some bacteria, however, are facultative anaerobes and can live with or without oxygen. If given the choice of using oxygen or not, which pathway should a facultative anaerobe perform?

• It doesn't matter; both processes will produce the same results.

• Use oxygen since aerobic metabolism provides more ATP per molecule of carbohydrate than anaerobic metabolism.

• Avoid using oxygen since anaerobic metabolism provides more ATP per molecule of carbohydrate than aerobic metabolism.

Which process reduces molecular oxygen to water?

• fermentation

• the preparatory reaction

• the citric acid cycle

• the electron transport system

The most important contribution of the citric acid cycle to cellular respiration is

• reduction of glucose and corresponding oxidation of carbon dioxide.

• production of large quantities of ATP.

• release of CO2.

• oxidation of metabolite molecules and the corresponding reduction of coenzymes.

During the preparatory reaction of aerobic respiration what happens to the carbon molecules?

• The carbon molecules are broken down from a 4-carbon to a 3-carbon acetyl group and a 2-carbon CO2 is released.

• The carbon molecules are broken down from a 3-carbon to a 1-carbon acetyl group and two 1-carbon CO2 are released.

• The carbon molecules are converted from a 2-carbon to a 3-carbon acetyl group and a 1-carbon CO2 is consumed

• The carbon molecules are broken down from a 3-carbon to a 2-carbon acetyl group and a 1-carbon CO2 is released.

The preparatory reaction converts

• pyruvates into glucose.

• glucose into pyruvates.

• pyruvates into acetyl CoA and carbon dioxide.

• pyruvates into acetyl CoA and water.

• acetyl CoA into pyruvates and carbon dioxide.