cellular respiration
How many molecules of carbon dioxide (CO2) would be released from the complete aerobic respiration of a molecule of sucrose (C12H22O11) a disaccharide?
12
Assume a mitochondrion contains 58 NADH and 19FADH2 If each of the 77 dinucleotides were used , approximately how many ATP molecules could be generated as a result of oxidative phosphorylation (chemiosmosis ) ?
212
Each time a molecule of glucose (C6H12O6) is completely oxidized via aerobic respiration, how many oxygen molecules (O2) are required?
6
Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose (C6H12O6) in cellular respiration ?
76
In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of
ATP, CO2, and ethanol (ethyl alcohol)
What is the term for metabolic pathways that release stored energy by breaking down complex molecules? a) anabolic pathways b) catabolic pathways c) fermentation pathways d) thermodynamic pathways e) bioenergetic pathways
B) catabolic pathways
Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
It is found in the cytosol, does not involve oxygen, and is present in most organisms.
A molecule that is phosphorylated A) has an increased chemical reactivity; it is primed to do cellular work. B) has a decreased chemical reactivity ; it is less likely to provide energy for cellular work C) has been oxidized as a result of a redox reaction involving the gain of an inorganic phosphate. D) has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate. E) has less energy than before its nophosphorylation and therefore less energy for cellular work.
a
A young relative of yours has never had much energy. He goes to a doctor for help and is sent to the hospital for some tests. There they discover his mitochondria can use only fatty acids and amino acids for respiration , and his cells produce more lactate than normal . Of the following , which is the best explanation of his condition ? A) His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane . B) His cells cannot move NADH from glycolysis into the mitochondria. C) His cells contain something that inhibits oxygen use in his mitochondria . D) His cells lack the enzyme in glycolysis that forms pyruvate . E) His cells have a defective electron transport chain , so glucose goes to lactate instead of to acetyl CoA .
a
During aerobic cellular respiration, a proton gradient in mitochondria is generated by and used primarily for A) the electron transport chain; ATP synthesis B) the electron transport chain ; substrate -level phosphorylation C) glycolysis ; production of H_{2}*O D) fermentation ; NAD^ + reduction E) diffusion of protons ; ATP synthesis
a
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate? A) 2 B) 4 C) 6 D) 8 E) 10
a
Starting with one molecule of isocitrate and ending with fumarate, what is the maximum number of ATP molecules that could be made through substrate -level phosphorylation ? A) 1 B) 2 C) 11 D) 12 E) 24
a
Which step consists of a phosphorylation reaction in which ATP is the phosphate source?
a
the ATP made during glycolysis is generated by a) substrate-level phosphorylation. b) electron transport. c) photophosphorylation. d) chemiosmosis. e) oxidation of NADH to NAD+
a
what is the term used for the metabolic pathway in which glucose (C6H12O6) is degraded to carbon dioxide (CO2) and water? a) cellular respiration b) glycolysis c) fermentation d) citric acid cycle e) oxidative phosphorylation
a
which statement is not correct with regard to redox (oxidation-reduction) reactions? a) a molecule is reduced if it loses electrons. b) a molecule is oxidized if it loses electrons. c) an electron donor is called a reducing agent. d) an electron acceptor is called an oxidizing agent. e) oxidation and reduction always go together.
a
Molecules that can potentially be converted to intermediates of glycolysis and/or the citric acid cycle include A) amino acids and proteins B) glycerol and fatty acids C) glucose and sucrose D) starch and glycogen E) all of the above
all of the above
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration ? A) glycolysis and the oxidation of pyruvate to acetyl CoA B) oxidation of pyruvate to acetyl CoA and the citric acid cycle C) the citric acid cycle and oxidative phosphorylation D) oxidative phosphorylation and fermentation E) fermentation and glycolysis
b
Cellular respiration harvests the most chemical energy from which of the following ? A) substrate-level phosphorylation B) chemiosmotic phosphorylation C) converting oxygen to ATP D) transferring electrons from organic molecules to pyruvate E) generating carbon dioxide and oxygen in the electron transport chain
b
In glycolysis , for each molecule of glucose oxidized to pyruvate A) 2 molecules of ATP are used and 2 molecules of ATP are produced . B) 2 molecules of ATP are used and 4 molecules of ATP are produced . C) 4 molecules of ATP are used and 2 molecules of ATP are produced . D) 2 molecules of ATP are used and 6 molecules of ATP are produced . E) 6 molecules of ATP are used and 6 molecules of ATP are produced.
b
It is possible to prepare vesicles from portions of the inner membrane of the mitochondrial components . Which one of the following processes could still be carried on by this isolated inner membrane ? A) the citric acid cycle B) oxidative phosphorylation C) glycolysis and fermentation D) reduction of NAD^ + E) both the citric acid cycle and oxidative phosphorylation
b
Starting with one molecule of glucose, the net" products of glycolysis are A) 2 NAD+, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O B) 2 NADH, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O C) 2FADH2, 2 pyruvate, 4 ATP, and 2 H2O D) 6 CO2, 6 H2O, 2 ATP, and 2 pyruvate E) 6 CO2, 6 H2O, 36 ATP, and 2 citrate
b
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction a) gains electrons and gains energy. b) loses electrons and loses energy. c) gains electrons and loses energy. d) loses electrons and gains energy. e) neither gains nor loses electrons, but gains or loses energy.
b
The oxygen consumed during cellular respiration is involved directly in which process or event? A) glycolysis B) accepting electrons at the end of the electron transport chain C) the citric acid cycle D) the oxidation of pyruvate to acetyl E) the phosphorylation of ADP to form ATP
b
The primary role of oxygen in cellular respiration is to A) yield energy in the form of ATP as it is passed down the respiratory chain . B) act as an acceptor for electrons and hydrogen , forming water . C) combine with carbon , forming CO2 D) combine with lactate , forming pyruvate. E) catalyze the reactions of glycolysis .
b
Which metabolic process is most closely associated with intracellular membranes? A) substrate -level phosphorylation B) oxidative phosphorylation C) glycolysis D) the citric acid cycle E) alcohol fermentation
b
Which process in eukaryotic cells will proceed normally whether oxygen (O2) present or absent? A) electron transport B) glycolysis C) the citric acid cycle D) oxidative phosphorylation E) chemiosmosis
b
Which step shows a split of one molecule into two smaller molecules?
b
During glycolysis, when glucose is catabolized to pyruvate, most of the energy of glucose is A) transferred to ADP, forming ATP. B) transferred directly to ATP. C) retained in the pyruvate. D) stored in the NADH produced. E ) used to phosphorylate fructose to form fructose-6-phosphate .
c
During oxidative phosphorylation , H2O is formed . Where does the oxygen for the synthesis of the water come from? A) carbon dioxide (CO2) B) glucose (C6H12O6) C) molecular oxygen (O2) D ) pyruvate (C 3 H 3 O 3 -) E) lactate (C 3 H 5 O 3 -)
c
How many ATP molecules could be made through substrate -level phosphorylation plus oxidative phosphorylation (chemiosmosis) if you started with three molecules of succinyl CoA and ended with oxaloacetate ? A) 6 B) 12 C) 18 D) 24 E) 36
c
How many molecules of carbon dioxide (CO2) would be produced by five turns of the citric acid cycle ? A) 2 B) 5 C) 10 D) 12 E) 60
c
How many reduced dinucleotides would be produced with four turns of the citric acid cycle ? A) 1 FADH2 and 4 NADH B) 2 FADH2 and 8 NADH C) 4 FADH2 and 12 NADH D) 1 FAD and 4 NAD+ E) 4 FAD+ and 12 NAD+
c
In addition to ATP, what are the end products of glycolysis? A) CO2 and H2O B) CO2 and pyruvate C) NADH and pyruvate D) CO2 and NADH E) H2O, FADH2, and citrate
c
In which step is an inorganic phosphate added to the reactant?
c
Where are the proteins of the electron transport chain located ? A) cytosol B) mitochondrial outer membrane C) mitochondrial inner membrane D) mitochondrial intermembrane space E) mitochondrial matrix
c
when a molecule of NAD+ gains a hydrogen atom (not a hydrogen ion) the molecule becomes a) hydrogenated. b) oxidized. c) reduced. d) redoxed. e) a reducing agent.
c
Carbon skeletons for amino acid biosynthesis are supplied by intermediates of the citric acid cycle. Which intermediate would supply the carbon skeleton for synthesis of a five-carbon amino acid? A) succinate B) malate C) citrate D) a-ketoglutarate E) isocitrate
d
Energy released by the electron transport chain is used to pump H^ + ions into which location ? A) cytosol B) mitochondrial outer membrane C) mitochondrial inner membrane D) mitochondrial intermembrane space E) mitochondrial matrix
d
In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + P_{i} to ATP ? A) energy released as electrons flow through the electron transport system B) energy released from substrate -level phosphorylation C) energy released from ATP synthase pumping hydrogen ions against their concentration gradient D) energy released from movement of protons through ATP synthase E) No external source of energy is required because the reaction is exergonic .
d
In the presence of oxygen, the three-carbon compound pyruvate can be catabolized in the citric acid cycle. First, however , the pyruvate 1 ) loses a carbon , which is given off as a molecule of C*O_{2} 2 ) is oxidized to form a two -carbon compound called acetate , and 3 ) is bonded to coenzyme A. These three steps result in the formation of A ) acetyl CoA , O2, and ATP . B ) acetyl CoA, FADH2, and CO2 C ) acetyl CoA , FAD, H2, CO2. D ) acetyl CoA, NADH, and H+, CO2 E ) acetyl CoA , NAD+, ATP , and CO2
d
Starting with citrate, how many of the following would be produced with three turns of the citric acid cycle ? A) 1 ATP, 2 CO2, 3 NADH, and 1 FADH2 B) 2 ATP, 2 CO2, 1 NADH, and 3 FADH2 C) 3 ATP, 3 CO2, 3 NADH, and 3 FADH2 D) 3 ATP, 6 CO2, 9 NADH, and 3 FADH2 E) 38 ATP, 6 CO2, 3 NADH , and 12FADH2
d
Starting with one molecule of citrate and ending with oxaloacetate, how many ATP molecules can be formed from oxidative phosphorylation (chemiosmosis )? A) 1 B) 3 C) 4 D) 11 E) 12
d
The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation is A) oxidation of glucose to C*O_{2} and water B ) the thermodynamically favorable flow of electrons from NADH to the mitochondrial electron transport carriers . C) the final transfer of electrons to oxygen. D) the difference in H^ + concentrations on opposite sides of the inner mitochondrial membrane . E ) the thermodynamically favorable transfer of phosphate from glycolysis and the citric acid cycle intermediate molecules of ADP.
d
When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space , the result is the A) formation of ATP . B) reduction of NAD^ + C) restoration of the Na^ + /K^ + balance across the membrane. D) creation of a proton gradient . E) lowering of pH in the mitochondrial matrix .
d
Where is ATP synthase located in the mitochondrion? A) cytosol B) electron transport chain C ) outer membrane D ) inner membrane E) mitochondrial matrix
d
Which of the following intermediary metabolites enters the citric acid cycle and is formed , in part , by the removal of a carbon (C*O_{2}) from one molecule of pyruvate ? A) lactate B) glyceraldehydes-3-phosphate C) oxaloacetate D) acetyl CoA E) citrate
d
Which of the following statements about glycolysis false? A) Glycolysis has steps involving oxidation-reduction reactions . B) The enzymes of glycolysis are located in the cytosol of the cell. C) Glycolysis can operate in the complete absence of O2. D) The end products of glycolysis are CO2 and H2O. E ) Glycolysis makes ATP exclusively through substrate-level phosphorylation.
d
All of the following are functions of the citric acid cycle except A) production of ATP. B) production of NADH C) production of FADH2 D) release of carbon dioxide. E) adding electrons and protons to oxygen, forming water.
e
During aerobic respiration , which of the following directly donates electrons to the electron transport chain at the lowest energy level ? A ) NAD+ B) NADH C) ATP D) ADP + Pi E) FADH2
e
During cellular respiration, acetyl CoA accumulates in which location? A) cytosol B) mitochondrial outer membrane C) mitochondrial inner membrane D) mitochondrial intermembrane space E) mitochondrial matrix
e
For each molecule of glucose that is metabolized by glycolysis and the citric acid cycle, what is the total number of NADH+ FADH2 molecules produced? A) 4 B) 5 C) 6 D ) 10 E) 12
e
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed during glycolysis? A) 0% B) 2% C) 10% D) 38% E) 100%
e
Where does glycolysis take place? a) mitochondrial matrix b) mitochondrial outer membrane. c) mitochondrial inner membrane. d) mitochondrial inter membrane space. e) cytosol.
e
which of the following statements is (are) correct about an oxidation-reduction (or redox) reaction? a) the molecule that is reduced gains electrons. b) the molecule that is oxidized loses electrons. c) the molecule that is reduced loses electrons. d) the molecule that is oxidized gains electrons. e) both a and b are correct.
e
The primary function of the mitochondrion is the production of ATP. To carry out this function , the mitochondrion must have all of the following except
enzymes for glycolysis
Which metabolic pathway is common to both cellular respiration and fermentation?
glycolysis
Which of the following normally occurs whether or not oxygen (O2) is present?
glycolysis
Which of the following occurs in the cytosol of the cell?
glycolysis and fermentation
Muscle cells in oxygen deprivation convert pyruvate to ________, and in this step gain ________.
lactate; NAD+
Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water?
oxidative phosphorylation (chemiosmosis)
The ATP made during fermentation is generated by which of the following?
substrate-level phosphorylation