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* Where does glycolysis occur?

Cytosol

* Where does acetyl CoA formation occur?

mito matrix

* Where does the CAC occur?

mito matrix

* Where does oxidative phosphorylation occur?

inner mito membrane

* 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 process in eukaryotic cells will proceed normally whether oxygen (O2) is present or absent?

glycolysis

* Why are carbohydrates and fats considered high energy foods?

They have a lot of electrons associated with hydrogen.

* Among the products of glycolysis, which compounds contain energy that can be used by other biological reactions?

pyruvate, ATP, and NADH

* Which kind of metabolic poison would most directly interfere with glycolysis?
A) an agent that reacts with oxygen and depletes its concentration in the cell
B) an agent that binds to pyruvate and inactivates it
C) an agent that closely mimics the structure of glucose but is not metabolized
D) an agent that reacts with NADH and oxidizes it to NAD+
E) an agent that blocks the passage of electrons along the electron transport chain

C) an agent that closely mimics the structure of glucose but is not metabolized

* A molecule that is phosphorylated
A) has been reduced as a result of a redox reaction involving the loss of an inorganic phosphate.
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 an increased chemical reactivity; it is primed to do cellular work.
E) has less energy than before its phosphorylation and therefore less energy for cellular work.

D) has an increased chemical reactivity; it is primed to do cellular work.

How many enzyme-catalyzed reactions occur in glycolysis

10

How many ATP are formed from Glycolysis?

2 net

How many NAHD are formed from Glycolysis?

2

* In glycolysis, what starts the process of glucose oxidation?

ATP

* In glycolysis there is a net gain of _____ ATP.

It takes 2 ATP to produce 4 ATP. = NET gain of 2

* In addition to ATP, what are the end products of glycolysis?
A) CO2 and pyruvate
B) CO2 and H2O
C) NADH and pyruvate
D) CO2 and NADH
E) H2O, FADH2, and citrate

C) NADH and pyruvate

* Why is glycolysis described as having an investment phase and a payoff phase?
A) It both splits molecules and assembles molecules.
B) It attaches and detaches phosphate groups.
C) It uses glucose and generates pyruvate.
D) It shifts molecules from cytosol to mitochondrion.
E) It uses stored ATP and then forms a net increasein ATP.

E) It uses stored ATP and then forms a net increase in ATP.

Part C - Why is the citric acid cycle a cyclic pathway rather than a linear pathway?

In the oxidation of pyruvate to acetyl CoA, one carbon atom is released as CO2. However, the oxidation of the remaining two carbon atoms—in acetate—to CO2 requires a complex, eight-step pathway—the citric acid cycle. Consider four possible explanations for why the last two carbons in acetate are converted to CO2 in a complex cyclic pathway rather than through a simple, linear reaction.

A- More ATP is produced per CO2 released in cyclic processes than in linear processes.

B- It is easier to remove electrons and produce CO2 from compounds with three or more carbon atoms than from a two-carbon compound such as acetyl CoA.

C- Redox reactions that simultaneously produce CO2 and NADH occur only in cyclic processes.

D- Cyclic processes, such as the citric acid cycle, require a different mechanism of ATP synthesis than linear processes, such as glycolysis.

B- It is easier to remove electrons and produce CO2 from compounds with three or more carbon atoms than from a two-carbon compound such as acetyl CoA.

* 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) oxidation of pyruvate to acetyl CoA and the citric acid cycle

* 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) 2

* 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) mitochondrial matrix

* How does pyruvate enter the mitochondrion?
A) active transport
B) diffusion
C) facilitated diffusion
D) through a channel
E) through a pore

A) active transport

* 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

A) acetyl CoA, O2, and ATP.
B) acetyl CoA, FADH2, and CO2.
C) acetyl CoA, FAD, H2, and CO2.
D) acetyl CoA, NADH, H+, and CO2.
E) acetyl CoA, NAD+, ATP, and CO2.

D) acetyl CoA, NADH, H+, and CO2.

* Which of these enters the citric acid cycle?

acetyl CoA
(Acetyl CoA is a reactant in the citric acid cycle.)

* In the citric acid cycle, ATP molecules are produced by _____.

substrate-level phosphorylation
(A phosphate group is transferred from GTP to ADP.)

* 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)

* Which of the following is an example of potential rather than kinetic energy?

A- a food molecule made up of energy-rich macromolecules

B- a boy mowing grass

C- an insect foraging for food

D- a firefly using light flashes to attract a mate

E- water rushing over Niagara Falls

A- a food molecule made up of energy-rich macromolecules

* Which molecule is metabolized in a cell to produce energy for performing work?

Glucose


Glucose is used to produce high-energy ATP in a cell.

* True or false? The potential energy in an ATP molecule is derived mainly from its three phosphate groups.

True


The three phosphate groups in an ATP molecule carry negative charges that strongly repel each other and give ATP a large amount of potential energy.

* Which process is not part of the cellular respiration pathway that produces large amounts of ATP in a cell?

Fermentation


Fermentation is an alternate pathway used when oxygen levels are low.

* Which step of the cellular respiration pathway can take place in the absence of oxygen?

Glycolysis


Glycolysis can take place in the absence of oxygen; its product, pyruvate, enters the cellular respiration pathway or undergoes fermentation depending on the availability of oxygen.

* Into which molecule are all the carbon atoms in glucose ultimately incorporated during cellular respiration?

Carbon dioxide


All of the carbon atoms in glucose are incorporated into carbon dioxide: Two molecules are formed as pyruvate is converted to acetyl CoA, and four molecules are formed during the Krebs cycle.

* Which of the following statements about the electron transport chain is true?

NADH and FADH2 donate their electrons to the chain.


The electrons lose energy as they move down the chain, and this energy is used to create a proton gradient that drives the synthesis of ATP.

* Which stage of glucose metabolism produces the most ATP?

Electron transport and chemiosmosis


Electron transport and chemiosmosis (oxidative phosphorylation) can yield around 26 molecules of ATP.

True or false? The reactions that generate the largest amounts of ATP during cellular respiration take place in the mitochondria.

True,


Glycolysis takes place in the cytoplasm, whereas the Krebs cycle and the electron transport chain, which generate the largest amounts of ATP during cellular respiration, take place in the mitochondria.

* In muscle cells, fermentation produces _____.

A. lactate and NAD+
B. carbon dioxide, ethanol, and NAD+
C. pyruvate
D. lactate, NADH, and ATP
E. carbon dioxide, ethanol, NADH, and ATP

A. lactate and NAD+

* In fermentation _____ is reduced and _____ is oxidized.

A. lactate ... NADH
B. pyruvate ... NADH
C. NAD+ ... pyruvate
D. lactate ... ethanol
E. NADH ... lactate

B. pyruvate ... NADH


The pyruvate from glycolysis is reduced to either lactate or ethanol, and NADH is oxidized to NAD+.

* Under anaerobic conditions (a lack of oxygen), the conversion of pyruvate to acetyl CoA stops.

A. Oxygen is an input to acetyl CoA formation

B. Oxygen is required to convert glucose to pyruvate in glycolysis. Without oxygen, no pyruvate can be made.

C. ATP is needed to convert pyruvate to acetyl CoA. Without oxygen, no ATP can be made in oxidative phosphorylation.

D. In the absence of oxygen, electron transport stops. NADH is no longer converted to NAD+, which is needed for the first three stages of cellular respiration.

Which of these statements is the correct explanation for this observation?

D. In the absence of oxygen, electron transport stops. NADH is no longer converted to NAD+, which is needed for the first three stages of cellular respiration.


NAD+ couples oxidative phosphorylation to acetyl CoA formation. The NAD+ needed to oxidize pyruvate to acetyl CoA is produced during electron transport. Without O2, electron transport stops, and the oxidation of pyruvate to acetyl CoA also stops because of the lack of NAD+.

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