Glucose Metabolism

Part A

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

	ADP
	Glucose
	ATP
	Phosphate

Correct

Glucose is used to produce high-energy ATP in a cell.

Part B

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

	True
	False

Correct

The three phosphate groups in an ATP molecule carry negative charges that strongly repel each other and give ATP a large amount of potential energy.

Part C

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

	Krebs cycle
	Fermentation
	Glycolysis
	Electron transport chain

Correct

Fermentation is an alternate pathway used when oxygen levels are low.

Part D

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

	Glycolysis
	Krebs cycle
	Electron transport chain
	Fermentation

Correct

Glycolysis can take place in the absence of oxygen; its product, pyruvate, enters the cellular respiration pathway or undergoes fermentation depending on the availability of oxygen.

Part E

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

	Carbon dioxide
	Water
	NADH
	ATP

Correct

All of the carbon atoms in glucose are incorporated into carbon dioxide: Two molecules are formed as pyruvate is converted to acetyl CoA, and four molecules are formed during the Krebs cycle.

Part F

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

	The electron transport chain is the first step in cellular respiration.
	NADH and FADH2 donate their electrons to the chain.
	Water is the last electron acceptor.
	Electrons gain energy as they move down the chain.

Correct

The electrons lose energy as they move down the chain, and this energy is used to create a proton gradient that drives the synthesis of ATP.

Part G

Which stage of glucose metabolism produces the most ATP?

	Krebs cycle
	Fermentation of pyruvate to lactate
	Glycolysis
	Electron transport and chemiosmosis

Correct

Electron transport and chemiosmosis (oxidative phosphorylation) can yield around 26 molecules of ATP.

Part H

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

	True
	False

Correct

Glycolysis takes place in the cytoplasm, whereas the Krebs cycle and the electron transport chain, which generate the largest amounts of ATP during cellular respiration, take place in the mitochondria.