BIO 205 CH 7

Which BEST describes energy production during cellular respiration? A small amount of energy is produced by oxidative phosphorylation; most is produced by substrate-level phosphorylation. A small amount of energy is produced by substrate-level phosphorylation; most is produced by oxidative phosphorylation. It depends on the organism. Some produce most of their energy by substrate-level phosphorylation, and some produce most of their energy by oxidative phosphorylation. None of the other answer options is correct. An equal amount is produced by oxidative phosphorylation and substrate-level phosphorylation.

A small amount of energy is produced by substrate-level phosphorylation; most is produced by oxidative phosphorylation.

For the potential energy of a proton gradient to be converted to the chemical energy of ATP, the movement of protons down their electrochemical gradient must be coupled with ATP synthesis. This coupling is made possible by: protein complex IV. cytochrome c. coenzyme Q. ATP synthase. oxygen.

ATP synthase.

Which of these reactions summarizes the overall reactions of cellular respiration? 6 CO2 + 6 O2 → C6H12O6 + 6 H2O C6H12O6 + 6 O2 + energy → 6 CO2 + 12 H2O C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy H2O → 2 H+ + 1/2 O2 + 2e- 6 CO2 + 6 H2O + energy → C6H12O6 + 6 O2

C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + energy

What happens to pyruvate during the process of fermentation? It is converted to pyruvic acid. It is reduced to ethanol. It is converted to acetyl-CoA. It is oxidized to ethanol. It is oxidized to lactic acid.

It is reduced to ethanol.

If oxygen is unavailable, predict what happens to the citric acid cycle. It stops because the supplies of NAD+ and FAD become depleted. It continues because none of the reactions in the citric acid cycle require oxygen. It stops because ADP levels increase in the absence of oxygen. It continues because ATP levels are low, and low ATP activates enzymes of the cycle.

It stops because the supplies of NAD+ and FAD become depleted.

Following the citric acid cycle but before the electron transport chain and oxidative phosphorylation, most of the energy from the original glucose molecule is found in: CO2. NADH. acetyl-CoA. ATP. pyruvate.

NADH

Which one of the following represents the REDUCED forms of the two major electron carriers? NAD+ and FAD NADH and FAD NADH and FADH2 NAD+ and FADH2

NADH and FADH2

Which of the following statements is TRUE regarding the equation C6H12O6 + 6O2 → 6CO2 + 6H2O + energy? The oxygen atoms in both CO2 and H2O are electronegative, and glucose is considered a reducing agent. Glucose could be considered a reducing agent. The oxygen atoms in both CO2 and H2O are electronegative. In the production of CO2 from glucose, the oxygen atoms lose electrons and the carbon atom is oxidized. The movement of hydrogen atoms in reactions involving C6H12O6 and H2O yields no information regarding the movement of electrons.

The oxygen atoms in both CO2 and H2O are electronegative, and glucose is considered a reducing agent.

Which of the following statements must be true in order for mitochondrial ATP synthase to function properly? The pH of the intermembrane space must be higher than the pH of the mitochondrial matrix. There must be no difference in pH between the mitochondrial matrix and the intermembrane space. The pH of the intermembrane space must be lower than the pH of the mitochondrial matrix.

The pH of the intermembrane space must be lower than the pH of the mitochondrial matrix.

When carbohydrates are oxidized, the C-H bonds of the carbohydrate become C=O bonds of carbon dioxide. Oxidation is defined as a loss of electrons, but carbon does not become positively charged in the process. Why then is this considered oxidation? The phosphate groups of ATP are ionized, and carbons donate those electrons. C=O bonds in CO2 are double bonds, and C-H bonds are single bonds. Electrons in the C=O bonds are higher energy than the electrons in the C-H bonds. The shared electrons in C-O bonds spend less time close to the carbon nucleus than the shared electrons in C-H bonds.

The shared electrons in C-O bonds spend less time close to the carbon nucleus than the shared electrons in C-H bonds.

Energy released by transferring electrons along the electron transport chain is stored as potential energy in the form of: ATP. redox couples. ATP synthase. a proton gradient. coenzyme Q.

a proton gradient.

Glycolysis is a series of chemical reactions (endergonic and exergonic) by which the cell can obtain ATP. NAD+ plays a crucial role in the reactions of glycolysis by: donating electrons to ADP to make ATP. accepting electrons from glucose, with the result that glucose is partially oxidized to pyruvate. donating electrons to pyruvate when glucose becomes partially oxidized. converting endergonic reactions to exergonic reactions so that there is an output of energy to make ATP.

accepting electrons from glucose, with the result that glucose is partially oxidized to pyruvate.

How did the earliest organisms on Earth most likely produce ATP? by the citric acid cycle by pyruvate oxidation by oxidative phosphorylation by glycolysis

by glycolysis

Cellular respiration is a series of _____ reactions. phosphorylation catabolic glycolytic carboxylation anabolic

catabolic

The majority of the energy generated in the citric acid cycle is in the form of: GTP produced by oxidative phosphorylation. ATP produced by substrate-level phosphorylation. GTP produced by substrate-level phosphorylation. ATP produced by oxidative phosphorylation. electrons donated to NAD+ and FAD+.

electrons donated to NAD+ and FAD+.

The proteins of the electron transport chain are: embedded in the inner mitochondrial membrane. embedded in the outer mitochondrial membrane. located in the mitochondrial matrix. located in the intermembrane space of mitochondria. embedded in both mitochondrial membranes.

embedded in the inner mitochondrial membrane.

The first phase of glycolysis requires the input of two ATP molecules. It is therefore: endergonic. reducing. None of the other answer options is correct. exergonic. oxidative.

endergonic

Which of the following molecules has the GREATEST potential energy? water carbon dioxide glucose

glucose

Which of the following takes place in the cytoplasm of eukaryotic cells? glycolysis and fermentation the citric acid cycle and oxidative phosphorylation pyruvate oxidation and the citric acid cycle fermentation and the citric acid cycle glycolysis and pyruvate oxidation

glycolysis and fermentation

When fats are used as an energy source, the fatty acids are broken down to acetyl-CoA. That means that fats bypass the reactions of _____ and enter the respiratory pathway at _____. fermentation; glycolysis oxidative phosphorylation; fermentation the citric acid cycle; oxidative phosphorylation the citric acid cycle; glycolysis glycolysis; the citric acid cycle

glycolysis; the citric acid cycle

Starting with glycolysis, lactic acid and ethanol fermentation generate only two ATP molecules per glucose molecule. The remaining chemical energy from the glucose is found primarily in: NADH. CO2. GTP. FADH2. lactic acid and ethanol.

lactic acid and ethanol.

In human cells such as muscle tissue, the product of fermentation is: acetic acid. FADH2. lactic acid. pyruvate. ethanol.

lactic acid.

The chemical bonds of carbohydrates and lipids have high potential energy because: they are strong oxidizing agents. many of these bonds are C—C and C—H bonds. they are easy to phosphorylate. they are easy to hydrolyze. they are strong reducing agents.

many of these bonds are C—C and C—H bonds.

An organism that carries out cellular respiration in its mitochondria: is a bacterium. may be any kind of cell. may be a prokaryotic cell from the domain Archaea. may be a cell from a terrestrial (land) plant.

may be a cell from a terrestrial (land) plant.

The citric acid cycle takes place in the: mitochondrial matrix. inner mitochondrial membrane. cytoplasm. intermembrane space of mitochondria. outer mitochondrial membrane.

mitochondrial matrix.

The energy in organic molecules is released in a series of steps because: more energy can be harvested for cellular use in multiple steps than from a single step. more total energy is released in multiple steps than would be released in a single step. only a single electron can be moved at a time in a cellular reaction. it is not possible to release it in a single step. less total energy is released in multiple steps than would be released in a single step.

more energy can be harvested for cellular use in multiple steps than from a single step.

Most of the ATP produced during cellular respiration is generated through: oxidation of pyruvate. substrate-level phosphorylation. oxidative phosphorylation. reduction of NAD+. reduction of FAD.

oxidative phosphorylation.

In cellular respiration, glucose is _____ to CO2 and oxygen is _____ to water. phosphorylated; deoxygenated reduced; oxidized deoxygenated; phosphorylated oxidized; reduced oxidized; oxidized

oxidized; reduced

What is the FINAL electron acceptor in the electron transport chain? oxygen ATP glucose ADP

oxygen

Which one of the following is NOT a product of cellular respiration? water oxygen ATP All of these choices are correct. carbon dioxide

oxygen

What glycolysis product is transported into the mitochondria? pyruvate glucose ATP NADP

pyruvate

Cellular respiration releases energy. In cellular respiration: chemical potential energy in the bonds of ADP is transferred to the chemical potential energy in the bonds of ATP. organic molecules such as carbohydrates are converted to chemical energy that can be used to do the work of the cell. the chemical potential energy stored in organic molecules is converted to chemical energy that can be used to do the work of the cell.

the chemical potential energy stored in organic molecules is converted to chemical energy that can be used to do the work of the cell.

In eukaryotic cells, the oxidation of pyruvate occurs in: the matrix of the mitochondria. the cytoplasm. vacuoles. the nucleus. the endoplasmic reticulum.

the matrix of the mitochondria.

At the end of glycolysis, the carbon molecules originally found in the starting glucose molecule are in the form of: four ATP molecules. one pyruvate molecule. two pyruvate molecules. two NADH molecules. two ATP molecules.

two pyruvate molecules.