Cellular Respiration
In glycolysis there is a net gain of _____ ATP.
2
For each glucose that enters glycolysis, _____ acetyl CoA enter the citric acid cycle.
2 (Each glucose produces two pyruvates, each of which is converted into acetyl CoA.)
what is the input(s) of glycolysis?
2 ATP, NAD+, glucose,
Starting with one molecule of glucose, the energy-containing products of glycolysis are
2 NAD+, 2 pyruvate, and 2 ATP.
Starting with one molecule of glucose, the "net" products of glycolysis are
2 NADH, 2 H+, 2 pyruvate, 2 ATP, and 2 H2O.
For each glucose that enters glycolysis, _____ NADH + H+ are produced by the citric acid cycle.
6 (3 NADH + H+ are produced per each acetyl CoA that enters the citric acid cycle.)
Approximately how many molecules of ATP are produced from the complete oxidation of two molecules of glucose (C6H12O6) in aerobic cellular respiration?
60-64
ATP synthase
ATP synthase phosphorylates ADP.
Which of the following intermediary metabolites enters the citric acid cycle and is formed, in part, by the removal of a carbon (CO2) from one molecule of pyruvate?
Acetyl CoA
what is the output(s) of citric acid cycle?
CO2, NADH, FADH2, ATP
The glucose molecule has a large quantity of energy in its _____. number of oxygen atoms polar structure C—N bonds C—H bonds
C—H bonds
Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells?
D) mitochondrial intermembrane space
what is the output(s) of electron transport chain?
NAD+, FADH, H2O
what is the input(s) of electron transport chain?
NADH, FADH2, Oxygen
What is the product(s) of the calvin cycle
NADP+, glucose
what is the input(s) of citric acid cycle?
acetyl coa, NAD+, FADH, ADP
Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in
all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron acceptors
In plant cells, glycolysis takes place in the
cytoplasm
Where does glycolysis occur?
cytoplasm
Which metabolic pathway is common to both cellular respiration and fermentation?
glycolysis
Which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
glycolysis
Which catabolic processes may have been used by cells on ancient Earth before free oxygen became available?
glycolysis, pyruvate oxidation, the citric acid cycle, and oxidative phosphorylation, using an electron acceptor other than oxygen
where does the calvin cycle occur?
stroma
The direct energy source that drives ATP synthesis during respiratory oxidative phosphorylation in eukaryotic cells is
the proton-motive force across the inner mitochondrial membrane
Even though plants carry on photosynthesis, plant cells still use their mitochondria for oxidation of pyruvate. When and where will this occur?
) in all cells all the time
Phosphofructokinase is an allosteric enzyme that catalyzes the conversion of fructose 6-phosphate to fructose 1,6-bisphosphate, an early step of glycolysis. In the presence of oxygen, an increase in the amount of ATP in a cell would be expected
) inhibit the enzyme and thus slow the rates of glycolysis and the citric acid cycle
During aerobic respiration, H2O is formed. Where does the oxygen atom for the formation of the water come from
) molecular oxygen (O2)
Each of the four stages of cellular respiration occurs in a specific location inside or outside the mitochondria. These locations permit precise regulation and partitioning of cellular resources to optimize the utilization of cellular energy. Match each stage of cellular respiration with the cellular location in which it occurs. Labels may be used once, more than once, or not at all. stage of cellular respiration: 1. glycolisis 2. acetyl CoA formation 3. citric acid cycle 4. oxidative phosphorylation Answer choices: cytosol intermembrane space mitochondrial matrix outer mitochondrial membrane inner mitochondrial membrane
1. cytosol 2. mitochondrial matrix 3. mitochondrial matrix 4. inner mitochondrial membrane
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed by the reactions of glycolysis?
100%
Substrate-level phosphorylation accounts for approximately what percentage of the ATP formed during glycolysis?
100%
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?
12
If a cell is able to synthesize 30 ATP molecules for each molecule of glucose completely oxidized by carbon dioxide and water, how many ATP molecules can the cell synthesize for each molecule of pyruvate oxidized to carbon dioxide and water
12
If a cell is able to synthesize 30 ATP molecules for each molecule of glucose completely oxidized to carbon dioxide and water, approximately how many ATP molecules can the cell synthesize for each molecule of pyruvate completely oxidized to carbon dioxide and water?
14
How many NADH are produced by glycolysis?
2
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate?
2
Glycolysis results in a net production of which of the following from each molecule of glucose?
2 NADH, 2 pyruvate, and 2 ATP
In glycolysis, for each molecule of glucose oxidized to pyruvate
2 molecules of ATP are used and 4 molecules of ATP are produced.
What fraction of the carbon dioxide exhaled by animals is generated by the reactions of the citric acid cycle, if glucose is the sole energy source?
2/3
what is the product(s) of glycolysis?
4 ATP, NADH, 2 pryruvates
How many oxygen molecules (O2) are required each time a molecule of glucose (C6H12O6) is completely oxidized to carbon dioxide and water via aerobic respiration
6
How many oxygen molecules (O2) are required each time a molecule of glucose (C6H12O6) is completely oxidized to carbon dioxide and water via aerobic respiration? 30 3 1 6 12
6
The complete oxidation of glucose (C6H12O6) to carbon dioxide and water in aerobic respiration consumes how many molecules of oxygen (O2)?
6
In glycolysis, what starts the process of glucose oxidation?
ATP
In a mitochondrion, if the matrix ATP concentration is high, and the intermembrane space proton concentration is too low to generate sufficient proton-motive force, then
ATP synthase will hydrolyze ATP and pump protons into the intermembrane space.
) Brown fat cells produce a protein called thermogenin in their mitochondrial inner membrane. Thermogenin is a channel for facilitated transport of protons across the membrane. What will occur in the brown fat cells when they produce thermogenin?
ATP synthesis will decrease, and heat generation will increase
What is the input(s) of the calvin cycle?
ATP, CO2, NADPH
In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of
ATP, CO2, and ethanol (ethyl alcohol).
Which of the following statements describes the results of this reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy
C6H12O6 is oxidized and O2 is reduced.
Which of the listed statements describes the results of the following reaction? C6H12O6 + 6 O2 → 6 CO2 + 6 H2O + Energy O2 is oxidized and H2O is reduced. C6H12O6 is reduced and CO2 is oxidized. CO2 is reduced and O2 is oxidized. O2 is reduced and CO2 is oxidized. C6H12O6 is oxidized and O2 is reduced.
C6H12O6 is oxidized and O2 is reduced.
Why is glycolysis described as having an energy investment phase and an energy payoff phase?
Early steps consume energy from ATP, and later steps store an increased amount of energy in ATP and NADH.
) Why does the oxidation of organic compounds by molecular oxygen to produce CO2 and water release free energy?
Electrons are being moved from atoms that have a lower affinity for electrons (such as C) to atoms with a higher affinity for electrons (such as O
During aerobic respiration, which of the following directly donates electrons to the electron transport chain at the lowest energy level?
FADH2
Which of these is NOT a product of glycolysis?
FADH2 (It is a product of the citric acid cycle.)
Which statement best supports the hypothesis that glycolysis is an ancient metabolic pathway that originated before the last universal common ancestor of life on Earth?
Glycolysis is widespread and is found in the domains Bacteria, Archaea, and Eukarya
) A young animal has never had much energy. He is brought to a veterinarian for help and is sent to the animal 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?
His mitochondria lack the transport protein that moves pyruvate across the outer mitochondrial membrane.
Why is glycolysis considered to be one of the first metabolic pathways to have evolved?
It does not involve organelles or specialized structures, does not require oxygen, and is present in most organisms.
Phosphofructokinase is an important control enzyme in the regulation of cellular respiration. Which of the following statements correctly describes phosphofructokinase activity?
It is an allosteric enzyme
) When an individual is exercising heavily and when the muscle becomes oxygen-deprived, muscle cells convert pyruvate to lactate. What happens to the lactate in skeletal muscle cells
It is taken to the liver and converted back to pyruvate.
Why is glycolysis described as having an investment phase and a payoff phase
It uses stored ATP and then forms a net increase in ATP.
Why is glycolysis described as having an investment phase and a payoff phase?
It uses stored ATP and then forms a net increase in ATP.
You have a friend who lost 7 kg (about 15 pounds) of fat on a regimen of strict diet and exercise. How did the fat leave her body?
It was released as CO2 and H2O.
The free energy for the oxidation of glucose to CO2 and water is -686 kcal/mol and the free energy for the reduction of NAD+ to NADH is +53 kcal/mol. Why are only two molecules of NADH formed during glycolysis when it appears that as many as a dozen could be formed?
Most of the free energy available from the oxidation of glucose remains in pyruvate, one of the products of glycolysis
What is the MOST IMPORTANT product of fermintation?
NAD+
Which of the following statements describes NAD+?
NAD+ is reduced to NADH during both glycolysis and the citric acid cycle.
Which of the following statements describes NAD+?
NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle
Which of the following statements about NAD+ is true? In the absence of NAD+, glycolysis can still function. NAD+ is oxidized by the action of hydrogenases. NAD+ has more chemical energy than NADH. NAD+ can donate electrons for use in oxidative phosphorylation. NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.
NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle.
Which of the following statements about NAD+ is true?
NAD+ is reduced to NADH during glycolysis.
During electron transport, energy from _____ is used to pump hydrogen ions into the _____.
NADH and FADH2 ... intermembrane space (The energy released as electrons, which have been donated by NADH and FADH2, is passed along the electron transport chain and used to pump hydrogen ions into the intermembrane space.)
In addition to ATP, what are the end products of glycolysis?
NADH and pyruvate
n addition to ATP, what are the end products of glycolysis?
NADH and pyruvate
The final electron acceptor of cellular respiration is _____.
Oxygen (Oxygen is combined with electrons and hydrogen to form water.)
When electrons move closer to a more electronegative atom, what happens?
The more electronegative reduced, and energy is released
A mutation in yeast makes it unable to convert pyruvate to ethanol. How will this mutation affect these yeast cells?
The mutant yeast will be unable to grow anaerobically
Why are carbohydrates and fats considered high energy foods
They have a lot of electrons associated with hydrogen.
Why are carbohydrates and fats considered high energy foods?
They have a lot of electrons associated with hydrogen.
In cellular respiration, the energy for most ATP synthesis is supplied by
a proton gradient across a membrane.
In the complete reactions of aerobic respiration, the energy for the majority of ATP synthesis is provided by
a proton gradient across a membrane.
Yeast cells grown anaerobically can obtain energy by fermentation, which results in the production of
a. ATP, CO2, and ethanol.This answer is correct.
The oxygen consumed during cellular respiration is involved directly in which process or event?
accepting electrons at the end of the electron transport chain
Which of these enters the citric acid cycle?
acetyl CoA (Acetyl CoA is a reactant in the citric acid cycle.)
Which of these is NOT a product of the citric acid cycle?
acetyl CoA (Acetyl CoA is a reactant in the citric acid cycle.) (ATP, FADH2, NADH + H+, CO2 are all products)
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 CO2, 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
acetyl CoA, NADH, H+, and CO2.
Where do the catabolic products of fatty acid breakdown enter into the citric acid cycle
acetyl coA
what is the output(s) of pyruvate oxidation?
acetyl coa, NADH, CO2
The primary role of oxygen in cellular respiration is to
act as an acceptor for electrons and hydrogen, forming water.
The transport of pyruvate into mitochondria depends on the proton-motive force across the inner mitochondrial membrane. How does pyruvate enter the mitochondrion
active transport
High levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in glycolysis. Citric acid binds to the enzyme at a different location from the active site. This is an example of
allosteric regulation.
Which kind of metabolic poison would most directly interfere with glycolysis
an agent that closely mimics the structure of glucose but is not metabolized
The synthesis of ATP by oxidative phosphorylation, using the energy released by movement of protons across the membrane down their electrochemical gradient, is an example of
an endergonic reaction coupled to an exergonic reaction.
What is the purpose of beta oxidation in respiration
breakdown of fatty acids
When skeletal muscle cells undergo anaerobic respiration, they become fatigued and painful. This is now known to be caused
build up of lactate
During intense exercise, as skeletal muscle cells go into anaerobiosis, the human body will increase its catabolism of
carb only
What is the term for metabolic pathways that release stored energy by breaking down complex molecules?
catabolic pathways
What is the term for metabolic pathways that release stored energy by breaking down complex molecules? catabolic pathways fermentation pathways thermodynamic pathways bioenergetic pathways anabolic pathways
catabolic pathways
Cellular respiration harvests the most chemical energy from which of the following?
chemiosmotic phosphorylation
ATP synthase occurs in the
chloroplast and mitochondria
Inside an active mitochondrion, most electrons follow which pathway
citric acid cycle → NADH → electron transport chain → oxygen
) When skeletal muscle cells are oxygen-deprived, the heart still pumps. What must the heart muscle cells be able to do?
continue aerobic metabolism when skeletal muscle cannot
When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the
creation of a proton gradient.
Where does glycolysis takes place?
cytosol
In animal cells, glycolysis occurs in the
cytosol.
In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP?
energy released from movement of protons through ATP synthase
) In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP?
energy released from movement of protons through ATP synthase, down the electrochemical gradient
An organism is discovered that thrives both in the presence and absence of oxygen in the air. Curiously, the consumption of sugar increases as oxygen is removed from the organism's environment, even though the organism does not gain much weight. This organism is
falcutative anerobe
During aerobic respiration, electrons travel downhill in which sequence
food → NADH → electron transport chain → oxygen
What carbon sources can yeast cells metabolize to make ATP from ADP under anaerobic conditions?
glucose
Yeast cells that have defective mitochondria incapable of respiration will be able to grow by catabolizing which of the following carbon sources for energy?
glucose
Which metabolic pathway is common to both cellular respiration and fermentation
glycolysis
Which of the following normally occurs regardless of whether or not oxygen (O2) is present
glycolysis
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent
glycolysis
Which process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?
glycolysis
Which of the following occur(s) in the cytosol of a eukaryotic cell?
glycolysis and fermentation
Which of the following occurs in the cytosol of a eukaryotic cell
glycolysis and fermentation
A molecule that is phosphorylated
has an increased chemical potential energy; it is primed to do cellular work
A molecule that is phosphorylated
has an increased chemical reactivity; it is primed to do cellular work.
During the light- reactions of photo synthesis, light energy is transformed into chemical energy and most of it is captured in the form of
high energy electrons
When oxygen is present, the pH in the matrix of the mitochondria is ____ compared to the intermembrane space
higher
Where does glycolysis take place in eukaryotic cells
in the cytosol
In prokaryotes, the respiratory electron transport chain is located
in the plasma membrane
In bacteria, ATP synthase is located
in the plasma membrane.
In liver cells, the inner mitochondrial membranes are about five times the area of the outer mitochondrial membranes. What purpose must this serve
increasing surface area for oxidative phosphorylation.
Where is ATP synthase located in the mitochondrion
inner membrane
Where is ATP synthase located in the mitochondrion?
inner membrane
Where are the proteins of the electron transport chain located?
inner mitochondrial membrane
The proximate (immediate) source of energy for oxidative phosphorylation is _____.
kinetic energy that is released as hydrogen ions diffuse down their concentration gradient (Concentration gradients are a form of potential energy.)
In the ____ of photosynthesis, NADP+ is _____ to form NADPH
light dependent reaction, oxidized
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction
loses electrons and loses energy.
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction
loses electrons and loses potential energy
The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction _____. loses electrons and loses potential energy loses electrons and gains potential energy gains electrons and loses potential energy gains electrons and gains potential energy neither gains nor loses electrons, but gains or loses potential energy
loses electrons and loses potential energy
In an oxidation-reduction reaction, the reducing agent
loses electrons and loses potential energy.
When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the intermembrane space, the result is the
lowering of pH in the mitochondrial matrix
Where does pyruvate oxidation occur?
mitochondria matrix
Where does the citric acid cycle occur?
mitochondria matrix
Where are the proteins of the electron transport chain located
mitochondrial inner membrane
Where are the proteins of the electron transport chain located?
mitochondrial inner membrane
Energy released by the electron transport chain is used to pump H+ ions into which location?
mitochondrial intermembrane space
During cellular respiration, acetyl CoA accumulates in which location
mitochondrial matrix
During cellular respiration, acetyl CoA accumulates in which location?
mitochondrial matrix
What kind of molecules serve as electron acceptors in cellular respiration? molecules with high potential energy molecules with low potential energy polar molecules water molecules in an excited state
molecules with low potential energy
In the last stage of cellular respiration, oxidative phosphorylation, all of the reduced electron carriers produced in the previous stages are oxidized by oxygen via the electron transport chain. The energy from this oxidation is stored in a form that is used by most other energy-requiring reactions in cells. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of oxidative phosphorylation. water glucose coenzyme A pyruvate ATP O2 ADP NAD+ CO2 Acetyl CoA NADH
net input: NADH, ADP, O2 net output: NAD+, ATP, water neither: acetyle CoA, coenzyme A, glucose, pyruvate, CO2
In the citric acid cycle (also known as the Krebs cycle), acetyl CoA is completely oxidized. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of the citric acid cycle. glucose coenzyme A pyruvate ATP O2 ADP NAD+ CO2 Acetyl CoA NADH
net input: acetyl CoA, ADP, NAD+ net output: coenzyme A, ATP, CO2, NADH neither:glucose, O2, pyruvate
In acetyl CoA formation, the carbon-containing compound from glycolysis is oxidized to produce acetyl CoA. From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of acetyl CoA formation. glucose coenzyme A pyruvate ATP O2 ADP NAD+ CO2 Acetyl CoA NADH
net input: coenzyme A, pyruvate, NAD+ net output: NADH, Acetyl CoA, CO2 neither: O2, ATP, ADP, glucose
From the following compounds involved in cellular respiration, choose those that are the net inputs and net outputs of glycolysis. glucose coenzyme A pyruvate ATP O2 ADP NAD+ CO2 Acetyl CoA NADH
net inputs: NAD+, glucose, ADP net outputs: ATP, pyruvate, NADH neither: coenzyme A, Acetyl CoA, CO2, O2
Carbon dioxide (CO2) is released during which of the following stages of cellular respiration
oxidation of pyruvate to acetyl CoA and the citric acid cycle
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?
oxidative phosphorylation
It is possible to prepare vesicles from portions of the inner mitochondrial membrane. Which one of the following processes could still be carried on by this isolated inner membrane
oxidative phosphorylation
In cellular respiration, most ATP molecules are produced by _____.
oxidative phosphorylation (This process utilizes energy released by electron transport.)
Which of the following produces the most ATP when glucose (C6H12O6) is completely oxidized to carbon dioxide (CO2) and water?
oxidative phosphorylation (chemiosmosis)
One function of both alcohol fermentation and lactic acid fermentation is to
oxidize NADH to NAD+
) When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the molecule becomes
oxidized
The final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is
oxygen
What is the product(s) of Light dependent reactions?
oxygen , ATP, NADPH
what is the input(s) of pyruvate oxidation?
pyruvate, NAD+
When a molecule of NAD+ (nicotinamide adenine dinucleotide) gains a hydrogen atom (not a proton), the molecule becomes
reduced
) In alcohol fermentation, NAD+ is regenerated from NADH by
reduction of acetaldehyde to ethanol (ethyl alcohol
Cells harvest energy stored in glucose molecules by
removing electrons
During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is
retained in the pyruvate
During glycolysis, when each molecule of glucose is catabolized to two molecules of pyruvate, most of the potential energy contained in glucose is
retained in the two pyruvates.
The primary role of oxygen in cellular respiration is to
serve as an acceptor for electrons and hydrogen, forming water.
An electron loses potential energy when it
shifts to a more electronegative atom.
The ATP made during fermentation is generated by which of the following?
substrate-level phosphorylation
The ATP made during glycolysis is generated by
substrate-level phosphorylation
In the citric acid cycle, ATP molecules are produced by _____.
substrate-level phosphorylation (A phosphate group is transferred from GTP to ADP.)
In glycolysis, ATP molecules are produced by _____.
substrate-level phosphorylation (A phosphate group is transferred from glyceraldehyde phosphate to ADP.)
The immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is
the H+ concentration gradient across the inner mitochondrial membrane.
when a cell metabolizes a glucose molecule, most of the energy is harvested in
the citric acid cycle
What is proton-motive force?
the force exerted on a proton by a transmembrane proton concentration gradient
As a result of the transfer of an electron from a less electronegative atom to a more electronegative atom,
the more electronegative atom is reduced, and energy is released.
where does the light dependent reaction occur?
thylakoid
In vertebrate animals, brown fat tissue's color is due to abundant blood vessels and capillaries. White fat tissue, on the other hand, is specialized for fat storage and contains relatively few blood vessels or capillaries. Brown fat cells have a specialized protein that dissipates the proton-motive force across the mitochondrial membranes. Which of the following might be the function of the brown fat tissue
to regulate temperature by converting most of the energy from NADH oxidation to heat
How many carbon atoms are fed into the citric acid cycle as a result of the oxidation of one molecule of pyruvate
two
In glycolysis, for each molecule of glucose oxidized to pyruvate
two molecules of ATP are used and four molecules of ATP are produced
What is the input(s) of light-dependent reactions of photosynthesis?
water and light
