Bio chapter 9 - Cellular Respiration & Fermentation

Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration?

Carbon dioxide

Which step of the cellular respiration pathway can take place in the absence of oxygen?

Glycolysis

True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups.

True

True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria.

True

In the citric acid cycle, ATP molecules are produced by

substrate-level phosphorylation

Acetyl Coa

CO2

Which molecule is metabolized in a cell to produce energy for performing work?

Glucose

Who is a reactant of the citric acid cycle?

Acetyl CoA

How would anaerobic conditions (when no O2 is present) affect the rate of electron transport and ATP production during oxidative phosphorylation? (Note that you should not consider the effect on ATP synthesis in glycolysis or the citric acid cycle.)

Both electron transport and ATP synthesis would stop.

Cellular respiration:

Cellular respiration and breathing differ in that cellular respiration is at the cellular level, whereas breathing is at the organismal level.

Which stage of glucose metabolism produces the most ATP?

Electron transport and chemiosmosis

Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell?

Fermentation

NADH and FADH2 are both electron carriers that donate their electrons to the electron transport chain. The electrons ultimately reduce O2 to water in the final step of electron transport. However, the amount of ATP made by electrons from an NADH molecule is greater than the amount made by electrons from an FADH2 molecule. Which statement best explains why more ATP is made per molecule of NADH than per molecule of FADH2?

Fewer protons are pumped across the inner mitochondrial membrane when FADH2 is the electron donor than when NADH is the electron donor.

What would happen to the cell's rate of glucose utilization?

Glucose utilization would increase a lot.

The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the

H+ concentration across the membrane holding ATP synthase.

Under anaerobic conditions (a lack of oxygen), the conversion of pyruvate to acetyl CoA stops. Which of these statements is the correct explanation for this observation?

In the absence of oxygen, electron transport stops. NADH is no longer converted to NAD+, which is needed for the first three stages of cellular respiration.

A glucose molecule is completely broken down to carbon dioxide and water in glycolysis and the citric acid cycle, but together these two processes yield only a few molecules of ATP. What happened to most of the energy that the cell obtains from the oxidation of glucose?

It is stored in NADH and FADH2

Match each product of pyruvate metabolism with the condition under which it is produced.

Lactate: Fermentation in human muscle ethanol: Fermentation in yeast and bacteria Acetyl CoA: Aerobic Oxidation

Which of the following statements about the electron transport chain is true?

NADH and FADH2 donate their electrons to the chain.

Fermentation:

Occurs in the absence of oxygen and does not yeild as much ATP.

Sort the following items according to whether they are reactants or products in the anaerobic reduction of pyruvate during lactic acid fermentation.

Reactants: NADH & Pyruvate Products: NAD+ & Lactate

What is the basic function of fermentation?

Regeneration of NAD+, which allows continued ATP production by glycolysis.

In cellular respiration, a series of molecules forming an electron transport chain alternately accepts and then donates electrons. What is the advantage of such an electron transport chain?

The advantage of an electron transport chain is that a small amount of energy is released with the transfer of an electron between each pair of intermediates.

In most cells, not all of the carbon compounds that participate in glycolysis and the citric acid cycle are converted to carbon dioxide by cellular respiration. What happens to the carbon in these compounds that does not end up as CO2?

The carbon compounds are removed from these processes to serve as building blocks for other complex molecules.

What is the function of a metabolic pathway involved in cellular respiration?

The function of glycolysis is to begin catabolism by breaking glucose into two molecules of pyruvate, with a net yield of two ATP. Glycolysis is the first stage in cellular respiration and does not depend on the presence of oxygen.

How will a healthy individual's ATP production change during an eight-hour fast?

The individual's ATP production will not change significantly.

Which statement about the citric acid cycle is correct?

The last reaction in the citric acid cycle produces a product that is a substrate for the first reaction of the citric acid cycle.

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

The pH of the matrix increases.

In the absence of oxygen, what is the net gain of ATP for each glucose molecule that enters glycolysis?

Two ATP are consumed to start the process of glycolysis and 4 ATP are made

The electrons stripped from glucose in cellular respiration end up in which compound?

Water at the end of the electron transport chain, the electrons and hydrogen atoms are added to oxygen, forming water.

The carbon compounds are removed from these processes to serve as building blocks for other complex molecules.

carbohydrates only.

Most CO2 from catabolism is released during

the citric acid cycle.

Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?

glycolysis

In muscle cells, fermentation produces _____.

lactate and NAD+

The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is

oxygen

In mitochondria, exergonic redox reactions

provide the energy that establishes the proton gradient.

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

pyruvate

In fermentation _____ is reduced and _____ is oxidized.

pyruvate ... NADH

In mitochondrial electron transport, what is the direct role of O2?

to function as the final electron acceptor in the electron transport chain