Chapter 7: Cellular Respiration and Fermentation
The function of cellular respiration is to _____.
extract usable energy from glucose
During the reaction C6H12O6 + 6 O2 → 6 CO2 + 6 H2O, which compound is reduced as a result of the reaction?
oxygen
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
the final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is __________.
oxygen
Which of the following accompanies the conversion of pyruvate to acetyl CoA before the citric acid cycle?
release of CO2 and synthesis of NADH
What is the oxidizing agent in the following reaction? Pruvate + NADH + H+ --> Lactate + NAD+
pyruvate
Most CO2 from catabolism is released during __________.
the citric acid cycle
Most of the NADH that delivers electrons to the electron transport chain comes from which of the following processes? ()
the citric acid cycle
The overall efficiency of respiration (the percentage of the energy released that is saved in ATP) is approximately _____.
35%
Which of the following substances is/are involved in oxidative phosphorylation?
ADP is converted to ATP during oxidative phosphorylation, and oxygen functions as the terminal electron acceptor in oxidative phosphorylation.
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.
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the __________.
H+ movement down its concentration gradient
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.
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 produced by the cell, less CO2 will be produced by the cell, and 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
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.
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.
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?
The chemiosmotic synthesis of ATP would stop in the mitochondria, but substrate-level phosphorylation could continue.
If muscle cells in the human body consume O2 faster than it can be supplied, which of the following is likely to result?
The first three answers are correct.
Most of the electrons removed from glucose by cellular respiration are used for which of the following processes?
The first two choices are correct.
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.
When electrons flow along the electron transport chains of mitochondria, which of the following changes occurs?
The pH of the matrix increases.
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.
When protein molecules are used as fuel for cellular respiration, _____ are produced as waste.
amino groups
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
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 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+
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 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
Of the metabolic pathways listed below, which is the only pathway found in all organisms?
glycolysis
Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
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?
glycolysis
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
During respiration in eukaryotic cells, the electron transport chain is located in or on the _____.
inner membrane of the mitochondrion
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
A molecule becomes more oxidized when it _____.
loses an electron
In mitochondria, exergonic redox reactions __________.
provide the energy that establishes the proton gradient
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
Muscle tissues make lactate from pyruvate to do which of the following?
regenerate NAD+
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
Where do the reactions of glycolysis occur in a eukaryotic cell?
the cytosol
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
Where do the reactions of the citric acid cycle occur in eukaryotic cells?
the matrix of the mitochondrion
Oxygen gas (O2) is one of the strongest oxidizing agents known. The explanation for this is that _____.
the oxygen atom is very electronegative
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
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
