Chapter 9 (Cellular Respiration and Fermentation) Flashcards
A molecule becomes more oxidized when it __________.
loses an electron
In the overall process of glycolysis and cellular respiration, __________ is oxidized and __________ is reduced.
glucose; oxygen
Most of the ATP produced in cellular respiration comes from which of the following processes?
Oxidative phosphorylation
Which of the following is a correct description of the events of cellular respiration in proper sequence?
Oxidation of glucose to pyruvate; oxidation of pyruvate; citric acid cycle; oxidative phosphorylation
Oxygen gas (O2) is one of the strongest oxidizing agents known. The explanation for this is that
the oxygen atom is very electronegative
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 statements is the best explanation of what happens to the temperature and carbon dioxide concentration during a 1-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.
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
Where do the reactions of glycolysis occur in a eukaryotic cell?
The cytosol
Which of the following is the process in which glucose is oxidized to generate two molecules of pyruvate and in which ATP and NADH are produced?
None of the listed responses is correct.
the name of the process that oxidizes glucose to pyruvate and produces ATP and NADH is 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
There is no production of carbon dioxide in glycolysis. Which of the following is the best explanation for this fact?
The products of glycolysis contain the same total number of carbon atoms as in the starting material.
Which of the following molecules in the process of glycolysis possesses the most chemical energy?
Fructose-1,6-bisphosphate
Which of the following processes generates most of the NADH that delivers electrons to the electron transport chain?
The citric acid cycle
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
In preparing pyruvate to enter the citric acid cycle, which of the following steps occurs?
Pyruvate is oxidized, and a molecule of carbon dioxide is removed. The electrons removed in this process are used to reduce NAD+ to NADH.
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.
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 FADH
Where do the reactions of the citric acid cycle occur in eukaryotic cells?
The matrix of the mitochondrion
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?
4
Which of the following represents the major energy-related accomplishment of the citric acid cycle, even though it is not the only energy-related accomplishment?
Formation of NADH and FADH2
After completion of the citric acid cycle, most of the usable energy from the original glucose molecule is in the form of __________.
NADH
Which of the following events accompanies the conversion of pyruvate to acetyl CoA before the citric acid cycle?
Release of CO2 and synthesis of NADH
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
Energy for synthesizing ATP is obtained by ATP synthase directly from which of the following processes?
The flow of H+ across the inner mitochondrial membrane through the ATP synthase enzyme
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.
Most of the electrons removed from glucose by cellular respiration are used for which of the following processes?
The first two choices are correct.
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.
Of the listed metabolic pathways, which is the only pathway found in all organisms?
Glycolysis
In brewing beer, maltose (a disaccharide of glucose) is __________. (
the substrate for alcoholic fermentation
Which of the following substances is/are involved in oxidative phosphorylation?
ADP
Oxygen
ATP
Which of the following is the source of the energy that produces the chemiosmotic gradient in mitochondria?
Movement of electrons down the electron transport chain
In eukaryotic cells, the components of the electron transport chain are located in or on __________.
the inner membrane of the mitochondrion
In glycolysis in the absence of oxygen, cells need a way to regenerate which compound?
NAD+
