Chapter 9: Cellular Respiration and Fermentation (Practice Test)

In the citric acid cycle, for each pyruvate that enters the cycle, one ATP, three NADH, and one FADH2 are produced. For each glucose molecule that enters glycolysis, how many ATP, NADH, and FADH2 are produced in the citric acid cycle?

two ATP, six NADH, two FADH2

A molecule becomes more oxidized when it

loses an electron

The overall efficiency of respiration (the percentage of the energy released that is saved in ATP) is approximately _____.

35%

During respiration in eukaryotic cells, the electron transport chain is located in or on the _____.

Inner membrane of the mitochondrion

Which of the following substances is/are involved in oxidative phosphorylation?

ADP, oxygen, ATP

When protein molecules are used as fuel for cellular respiration, _____ are produced as waste.

Amino Group

In an experiment, mice were fed glucose (C6H12O6) containing a small amount of radioactive oxygen. The mice were closely monitored, and after a few minutes radioactive oxygen atoms showed up in _____.

Carbon Dioxide

Which of the following best describes the electron transport chain?

Electrons are passed from one carrier to another, releasing a little energy at each step.

A gram of fat oxidized by respiration produces approximately twice as much ATP as a gram of carbohydrate. Which of the following best explains this observation?

Fats are better electron donors to oxygen than are sugars

Which of the following represents the major (but not the only) energy accomplishment of the citric acid cycle?

Formation of NADH and FADH2

How many molecules of ATP are gained by substrate-level phosphorylation from the complete breakdown of a single molecule of glucose in the presence of oxygen?

Four

Of the metabolic pathways listed below, which is the only pathway found in all organisms?

Glycolysis

Each ATP molecule contains about 1% of the amount of chemical energy available from the complete oxidation of a single glucose molecule. Cellular respiration produces about 32 ATP from one glucose molecule. What happens to the rest of the energy in glucose?

It is converted to heat

Sports physiologists at an Olympic training center wanted to monitor athletes to determine at what point their muscles were functioning anaerobically. They could do this by checking for a buildup of which of the following compounds?

Lactate

If significant amounts of materials are removed from the citric acid cycle to produce amino acids for protein synthesis, which of the following will result?

Less ATP will be produce by the cell; Less CO2 will be produced by the cell; The four-carbon compound that combines with acetyl CoA will have to be made by some other process

In glycolysis in the absence of oxygen, cells need a way to regenerate which compound?

NAD+

When a poison such as cyanide blocks the electron transport chain, glycolysis and the citric acid cycle also eventually stop working. Which of the following is the best explanation for this?

NAD+ and FAD are not available for glycolysis and the citric acid cycle to continue.

After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of _____.

NADH

If a compound that allows protons to freely diffuse across membranes is added to cells that are actively metabolizing glucose via cellular respiration, which of the following processes would stop?

Not ATP synthesis, electron transport, glycolysis

Which process is the one in which glucose is oxidized to generate two molecules of pyruvate, and in which ATP and NADH are produced?

Not the citric acid cycle, the oxidation of pyruvate, chemiosmosis, fermentation

During the reaction C6H12O6 + 6 O2 → 6 CO2 + 6 H2O, which compound is reduced as a result of the reaction?

Oxygen

The energy given up by electrons as they move through the electron transport chain is used in which of the following processes?

Pumping H+ across a membrane

In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs?

Pyruvate is oxidized and decarboxylated, and the removed electrons are used to reduce an NAD+ to an NADH.

Most of the electrons removed from glucose by cellular respiration are used for which of the following processes?

Reducing NAD+ to NADH in glycolysis and the citric acid cycle; producing a proton gradient for ATP synthesis in the mitochondria

Muscle tissues make lactate from pyruvate to do which of the following?

Regenerate NAD+

Which of the following accompanies the conversion of pyruvate to acetyl CoA before the citric acid cycle?

Release of CO2 and synthesis of NADH

When solid tumors of animals reach a certain size, the center of the tumor begins to die. To prevent this, the tumor can recruit new blood vessels. What purpose does the recruitment of blood vessels to growing tumors serve?

Supplies glucose to the rapidly dividing ells of the tumor; supplies a non-oxygen electron acceptor to cells so that the cells can respire anaerobically

Which of the following statements is the best explanation of what happens to the temperature and carbon dioxide concentration during a one-hour class period in a classroom of 300 students if the heating and air conditioning is turned off and all doors are kept closed?

Temperature and the level of carbon dioxide rise as heat and carbon dioxide are by-products of cellular respiration.

Where do the reactions of glycolysis occur in a eukaryotic cell?

The Cytosol

Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes?

The citric acid cycle

Why is the citric acid cycle called a cycle?

The four-carbon acid that accepts the acetyl CoA in the first step of the cycle is regenerated by the last step of the cycle.

Where do the reactions of the citric acid cycle occur in eukaryotic cells?

The matrix of the mitochondrion

If muscle cells in the human body consume O2 faster than it can be supplied, which of the following is likely to result?

The muscle cells will have more trouble making enough ATP to meet their energy requirements; the cells will not be able to carry out oxidative phosphorylation; the cells will consume glucose at an increased rate

In glycolysis, there is no production of carbon dioxide as a product of the pathway. Which of the following is the best explanation for this?

The products of glycolysis contain the same total number of carbon atoms as in the starting material.

During aerobic respiration, molecular oxygen (O2) is used for which of the following purposes?

at the end of the electron transport chain to accept electrons and form H2O

Which of the following is the source of the energy that produces the chemiosmotic gradient in mitochondria?

electrons moving down the electron transport chain

Fermentation is essentially glycolysis plus an extra step in which pyruvate is reduced to form lactate or alcohol and carbon dioxide. This last step _____.

enables the cell to recycle the reduced NADH to oxidized NAD+

The function of cellular respiration is to _____.

extract usable energy from glucose

Of the following molecules in the glycolytic pathway (the process of glycolysis), the one with the most chemical energy is _____.

fructose-1,6-bisphosphate

In the overall process of glycolysis and cellular respiration, _____ is oxidized and _____ is reduced.

glucose ... oxygen

A chemist has discovered a drug that blocks phosphoglucoisomerase, an enzyme that catalyzes the second reaction in glycolysis. He wants to use the drug to kill bacteria in people with infections. However, he cannot do this because

human cells must also perform glycolysis; the drug might also poison them

Which of the following is a correct description of the events of cellular respiration and the sequence of events in cellular respiration?

oxidation of glucose to pyruvate; oxidation of pyruvate; oxidation of acetyl-coA; oxidative phosphorylation

Most of the ATP produced in cellular respiration comes from which of the following processes?

oxidative phosphorylation

Which part of the catabolism of glucose by cellular respiration requires molecular oxygen (O2) and produces CO2?

the combination of the citric acid cycle and electron transport

The ATP synthase in a human cell obtains energy for synthesizing ATP directly from which of the following processes?

the flow of H+ across the inner mitochondrial membrane through the ATP synthase enzyme

Oxygen gas (O2) is one of the strongest oxidizing agents known. The explanation for this is that _____.

the oxygen atom is very electronegative

In brewing beer, maltose (a disaccharide of glucose) is _____.

the substrate for alcoholic fermentation

A small amount of ATP is made in glycolysis by which of the following processes?

transfer of a phosphate group from a fragment of glucose to ADP by substrate-level phosphorylation