Biology Chapters 6/7

A chemical reaction that has a positive ΔG is correctly described as
endergonic.
endothermic.
enthalpic.
spontaneous
exothermic.

A logical consequence of the second law of thermodynamics could be stated, ___.
if the entropy of a system increases, there must be a corresponding decrease in the entropy of the universe.
if there is an increase in the energy of a system, there must be a corresponding decrease in the energy of the rest of the universe.
every energy transfer requires activation energy from the environment.
every chemical reaction must increase the total entropy of the universe.
energy can be transferred or transformed, but it cannot be created or destroyed.

You measure the amount of enzyme activity in the presence of compound X and note that as you add more substrate the amount of enzyme activity increases. This indicates that the compound X is a _____.
Competitive inhibitor
Non-competitive inhibitor
Allosteric inhibitor.
Activator.
Enzyme.

In a catabolic reaction, electrons from food are…
removed by oxidation and stored in NADH
removed by reduction and stored in NADH
added by oxidation and stored in ATP
added by reduction and stored in NADH
added by reduction and stored in ATP

Patients with Parkinson’s Disease have been shown to have a block in the movement of autophagosomes towards lysosomes. Predict a condition that could result from this defect?
An accumulation of old or damaged mitochondria
An accumulation of glycogen
An accumulation of old or damaged proteins
A lack of lysosomes in the cell

Catabolic and anabolic reactions in living cells involve the transfer of electrons from one molecule to another in reduction-oxidation reactions.
True
False

Once ATP donates its phosphate to a coupled reaction it becomes ADP. The ADP can be converted back to ATP in a(an) ____ reaction.
endergonic
exergonic
equilibrium
hydrolysis
oxidation

What would your predict about the reaction Pi + ADP -> ATP
It has a change in free energy that is less than 0.
It has a change in free energy that is greater than 0.
It can be used to drive endergonic reactions.
It yields energy.
It has a change in free energy that is greater than 0, and hence can be used to drive endergonic reactions.

How does an enzyme work to catalyze a reaction?
It supplies the energy to speed up a reaction.
It allows the reaction to proceed through different intermediates.
It raises the temperature of a reaction.
It increases the concentration of the reactants in a reaction.
It lowers the activation energy of a reaction.

_____ will accumulate if a cell is treated with a proteasome inhibitor.
Unfolded proteins with ubiquitin attached
Digested proteins
Amino acids
Secreted proteins
Native proteins

In ALL exergonic reactions, ___.
the products have more total energy than the reactants.
the reaction proceeds with a net release of free energy.
some reactants will be converted to products.
a net input of energy from the surroundings is required for the reactions to proceed.
the reactions are nonspontaneous.

Your liver produces 90% of the cholesterol found in your body. When cholesterol levels get too high, the first enzyme in the pathway of cholesterol synthesis is inhibited. This is an example of:
Negative feedback
Positive feedback
Denaturation
Equilibrium
A coenzyme

Patients with McArdle’s Disease lack an enzyme in their livers that catabolizes glycogen. These individuals tire easily during exercise. Which of the following would best explain this symptom?
Glycogen must be broken down to glucose to be used in metabolism.
Glycogen is released from the liver into the blood by the enzyme.
Glycogen synthesis increases the energy available to cells during exercise.
Glycogen is produced from glucose in the blood and then stored in the liver.

If an enzyme catalyzes the reaction A + B –> C, then _____.
the active site of the enzyme binds C more tightly than A and B.
once the enzyme binds A and B it goes through a conformational change.
the enzyme energizes A and B to make them more reactive.
the enzyme will also catalyze the reaction C –> A + B
the enzyme could also convert A + B to another molecule D.

Ubiquitin ____.
recognizes improperly folded proteins.
targets proteins for degradation.
targets proteins for post-translational processing.
recognizes improperly folded proteins and targets them for degradation.
targets proteins for degradation and post-translational processing.

If one were to double the amount of enzyme in a reaction with an initial ΔG of -5 kcal/mole, what would the ΔG be?
-5 kcal/mole
-10 kcal/mole
-20 kcal/mole
+5 kcal/mole
+10 kcal/mole

The process of breaking glycogen down to glucose is an example of: ____.
catalysis
metabolism
anabolism
dehydration
catabolism

Temperature, pH, and ionic concentrations each play an important role in the proper functioning of enzymes.
True
False

An autotroph captures energy from other sources and does not actually produce energy because ____.
the transfer of energy increases the disorder of a system.
the transfer of energy increases entropy.
energy cannot be created or destroyed.
once energy is created it can be destroyed.
kinetic energy is based on location.

Protein degradation in eukaryotes is performed by ____.
cytoskeleton
flagellum
ribosome
ATP synthase
proteasome

A reaction that has a _____ would require being coupled to the hydrolysis of at least two ATP molecules (ΔG = -14.6 kCal) in order to occur.
ΔG = -8 kCal
ΔG = +8 kCal
ΔG = -16 kCal
ΔG = +16 kCal
ΔG = -14.6 kCal

The charge on amino acids in the active site of an enzyme would be affected by ___.
pH
temperature
salt concentration
antibiotics
substrate concentration

Enzymes are consumed in chemical reactions and must therefore be replenished.
True
False

A reaction with a ΔG 0 is endergonic and requires a net input of energy to proceed.
True
False

In photosynthesis, carbon dioxide gas is reduced and combined to form glucose. This is an example of…
exergonic
catabolism
metabolism
hydrolysis
anabolism

Which would be TRUE if an inhibitor blocked the activity of mitochondrial ATP synthase?
The pH in the space between the mitochondrial membranes would decrease.
The pH in the space between the mitochondrial membranes would increase.
ATP synthesis would increase.
Oxygen consumption would decrease.
The concentration of NADH would increase.

Assuming that the glycerol backbone of a fat molecule can be converted to glyceraldehyde-3-phosphate, an intermediate in glycolysis, how many ATP can be produced from the glycerol backbone of a fat molecule?
2
8
12
18
36

The aerobic breakdown of glucose yields 34 to 38 ATP, while the anaerobic breakdown of glucose yields 20 ATP.
True
False

Which occurs only in anaerobic metabolism of glucose?
citric acid cycle
glycolysis
acetyl CoA formation
oxidative phosphorylation
lactate fermentation

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 the buildup of which molecule?
ATP
lactate
carbon dioxide
ADP
oxygen

Proteins and fats may be used as energy sources to drive aerobic respiration.
True
False

During the cleavage stage of glycolysis, fructose-1, 6 biphosphate is broken down into
citric acid.
two molecules of pyruvate.
two molecules of ATP.
two molecules of glyceraldehyde-3-phosphate.
glucose.

The formation of each pyruvate in glycolysis also produces a net of 2 NADH and 2 ATP. However, each metabolism of glucose produces a net of 4 NADH and 4 ATP. How is this explained?
Glucose is cleaved into two three carbon sugars that are metabolized into pyruvate.
Glucose is metabolized by a different, more efficient pathway than pyruvate.
Energy is added to glucose which increases the amount of ATP produced per glucose molecule.
Pyruvate can also be fermented, which decreases the energy produced.

During the energy investment phase of glycolysis, glucose has a decrease in free energy.
True
False

When scientists placed ATP Synthase linked to fluorescent actin on a microscope slide and added ATP, the actin could be seen spinning. If the scientists instead added ADP what would happen?
The actin would not spin because it required ATP hydrolysis.
The actin would not spin because only ATP can move through the channel in ATP synthase.
The actin would spin because ADP can also move through the channel in ATP synthase.
The actin would spin when ADP is phosphorylated to form ATP.

In the reaction: pyruvate + CoA + NAD+ → acetyl CoA + CO2 + NADH.
Pyruvate is oxidized and NAD+ is reduced.
Pyruvate is reduced and NAD+ is oxidized.
Pyruvate is oxidized and CoA is reduced.
Pyruvate is reduced and CoA is oxidized.

The ability of bread to rise is mainly a function of the CO2 produced anaerobically during oxidative phosphorylation.
True
False

Substrate phosphorylation occurs when protons pass through ATP synthase and combine with oxygen to make water.
True
False

In the citric acid cycle, some intermediates are used in other metabolic reactions. Which of the following adaptations would need to be made by a cell in response to this?
Some oxaloacetate would need to be produced through an alternative pathway to combine with acetyl CoA.
Some citrate would need to be produced through an alternative pathway to combine with acetyl CoA.
The citric acid cycle would eventually shut down when it ran out of intermediates and the cell would switch to glycolysis.
Cells would have to use energy sources other than glucose for metabolism.

Where does glycolysis takes place?
mitochondrial matrix
mitochondrial membrane
mitochondrial inner membrane
mitochondrial intermembrane space
cytosol

The conversion of pyruvate to acetyl CoA is irreversible. Predict what would happen to fatty acids as a result of this.
Fatty acids cannot be converted into carbohydrates.
Fatty acids cannot be metabolized in the citric acid cycle.
Fatty acids can be metabolized in glycolysis.
Fatty acids can be converted into carbohydrates.

How many net ATP and NADH molecules are produced from one molecule of glucose during glycolysis?
4 ATP, 2 NADH
3 ATP, 4 NADH
2 ATP, 6 NADH
2 ATP, 2 NADH
0 ATP, 6 NADH

Which of the following statements about the electron transport chain in cell respiration is CORRECT?
Electrons move from NADH to a chain of proteins with lower electronegativities.
The electron transport chain of proteins uses ATP to pump H+ across the inner mitochondria membrane against its electrochemical gradient.
The loss in free energy of the electron initially donated by NADH is used to transport H+ across the inner mitochondrial membrane against its electrochemical gradient.
The electron transport chain of proteins contains pores that are leaky to H+.
The ATP synthase generates a H+ gradient across the inner mitochondrial membrane.

When heart muscles cells are deprived of oxygen, the heart still pumps. What must the heart cells be able to do?
derive sufficient energy from fermentation
continue aerobic metabolism when skeletal muscle cannot
transform lactate back to pyruvate
remove lactate from the blood
remove oxygen from lactate

Some bacteria can use sulfur instead of oxygen as a final electron acceptor. What would they produce during anaerobic respiration?
H2S
S2
H2O
O2

The ATP made during glycolysis is generated by
substrate-level phosphorylation.
electron transport.
photophosphorylation.
chemiosmosis.
oxidation of NADH to NAD+

In the citric acid cycle, the acetyl group is removed from acetyl CoA and attached to oxaloacetate to form
fumarate.
succinate.
citrate.
malate.
oxaloacetate.

The proton motive force requires that the H+ concentration is lower in the intermembrane space than inside the matrix.
True
False

The reaction of ethanol fermentation is: pyruvate + NADH → ethanol + CO2 + NAD+. Why would a yeast need to perform this reaction in the absence of oxygen?
To produce NAD+ allowing glycolysis to continue.
To produce NAD+ allowing the electron transport chain to run.
To produce CO2 for respiration.
To consume excess pyruvate that cannot enter the Krebs cycle.
NADH is necessary to reduce pyruvate to lactate.

How many ATP and NADH molecules are produced from each molecule of glucose in the citric acid cycle only?
4 ATP, 2 NADH
3 ATP, 4 NADH
2 ATP, 6 NADH
1 ATP, 2 NADH
0 ATP, 6 NADH

All of the following are a form of potential energy that can be used by a cell EXCEPT
ATP.
nitrogen.
an electrical/ion gradient.
concentration gradient.
NADH.

Water held behind a dam would best reflect ______.
potential energy
kinetic energy
chemical energy
heat energy
mechanical energy

Patients with McArdle’s Disease lack an enzyme in their livers that catabolizes glycogen. Compared to an unaffected individual you would predict that a patient with McArle’s disease would ______.
have an enlarged liver because they accumulate glycogen.
have increased autophagy of glycogen.
have increased breakdown of glycogen by proteaosomes.

Autophagy is an important process that removes worn-out organelles, recycles components, then release them into the cytosol.
True
False

The primary function of an enzyme or any biological catalyst is to
reduce the energy of activation of a reaction.
increase the rate of a reaction.
change the direction of a reaction.
reduce the energy of activation and increase the rate of a reaction.
increase the rate of a reaction and change the direction of a reaction.

For a reaction to be spontaneous it must show a net decrease in both energy and entropy.
True
False

Altering the three-dimensional structure of an enzyme might
change the amount of energy needed for a reaction.
prevent the substrate from binding the enzyme’s active site.
change the type of substrate that binds the enzyme’s active site.
change the type of product produced in the reaction.
prevent the enzyme from adding energy to a reaction.

The half-life of a molecule is the time it takes for 50% of the molecule to be broken down and recycled.
True
False

Noncompetitive inhibitors bind the active site of an enzyme, reducing its activity and the subsequent formation of product.
True
False

The amount of available energy that can be used to do work is called
enthalpy.
entropy.
free energy.
kinetic energy.
heat.

Patients with McArdle’s Disease lack an enzyme in their livers that catabolizes glycogen. Compared to an unaffected individual you would predict that a patient with McArdle’s disease would ______.
Have lower blood glucose levels because they cannot break down glycogen.
Have higher blood glucose levels because they cannot break down glycogen.
Have lower blood glucose levels because they cannot make glycogen.
Have higher blood glucose levels because they cannot make glycogen.
Have the same blood glucose levels because glycogen is made up of amino acids.

The reaction phosphoenolpyruvate + ADP → pyruvate + ATP (ΔG = -7.5 kcal/mole), ___
requires that energy is being transferred from phosphoenolpyruvate to ADP.
requires that energy is being transferred from ADP to phosphoenolpyruvate.
is an endergonic reaction.
is not spontaneous.
consumes energy.

Oxygen is an excellent final electron acceptor because of its low electronegativity.
True
False

The equation, C6H12O6 + 6O2 →6CO2 + 6H2O (ATP + Heat), describes which of the following processes?
photosynthesis
cell respiration
cell fermentation
glycolysis
anaerobic metabolism

In a PET scan a patient is injected with radioactively labeled glucose. Cancer cells are often in a hypoxic environment, why would this lead to an increase in glucose uptake?
They rely more on glycolysis which is less efficient than oxidative phosphorylation.
Because they require more oxygen to metabolize glucose.
They rely more on oxidative phosphorylation which is less efficient than glycolysis.
More energy is produced from glucose in hypoxic conditions.
Enzymes function more efficiently in the absence of oxygen.

Glycolysis involves 10 enzyme-catalyzed steps, that can be grouped into three phases: energy investment phase, cleavage phase, and the energy liberation phase.
True
False

High-energy electrons from molecules of NADH and FADH2 are transferred to a chain of proteins within the electron transport chain. What is the final protein in the electron transport chain?
carbon dioxide
oxygen
cytochrome c
ubiquinone
NAD+

When scientists placed ATP Synthase linked to fluorescent actin on a microscope slide and added ATP, the actin could be seen spinning counterclockwise. If the experiment could be replicated in a cell going through oxidative phosphorylation what would happen?
The actin would spin clockwise because ATP would be produced instead of hydrolyzed.
The actin would spin counterclockwise because ATP would be hydrolyzed.
The actin would spin counterclockwise because ATP would be produced instead of hydrolyzed.
The actin would spin clockwise because ATP would be hydrolyzed.

In the equation, C6H12O6 + 6O2 → 6CO2 + 6H2O, ATP and heat would be on which side of the reaction?
The products because this is an exergonic reaction.
The products because this is an endergonic reaction.
The reactants because this is an exergonic reaction.
The reactants because this is an endergonic reaction.
It could appear on either size because this reaction is in equilibrium.

In addition to ATP, what are the end products of glycolysis?
CO2 and NADH
CO2 and pyruvate
H2O, NADH, and citrate
NADH and pyruvate
CO2 and H2O

Bacteria that produce nitrite (NO2-) during anaerobic respiration would use ___ as their final electron acceptor.
NO3-
N2
N2O
O2

If an athlete is burning glucose only, predict the ratio of oxygen consumed to carbon dioxide that will be produced.
C6H12O6 + 6O2 → 6CO2 + 6H2O
1:1
1:2
2:1
6:1
1:6

Which of the following do yeast produce during fermentation?
Ethanol.
NADH.
Lactate.
Pyruvate.
Glucose.

Which of the following are produced during the citric acid cycle?
ATP and NAD+.
Oxygen.
ATP, NADH, and FADH2.
Pyruvate, ATP and NADH.
A proton gradient.

Metabolism refers to only those reactions that release energy.
True
False

In the reaction A- +B →A + B-, ____
molecules A and B are both reduced.
molecules A and B are both oxidized.
molecule A is oxidized and molecule B is unchanged.
molecule A is reduced and molecule B is oxidized.
molecule A is oxidized and molecule B is reduced.

A bowl of sugar water is very stable. But if you feed it to cells it is rapidly broken down into carbon dioxide and water. What is the best explanation for this observation?
Enzymes in the cell catalyze the breakdown of glucose.
Cells use energy to break down glucose.
Glucose becomes more chemically reactive inside a cell.
Glucose cannot be broken down outside a cell.
Glucose is removed from the cell by active transport.

The primary complexes for protein synthesis and degradation in eukaryotes are _____ and _____ respectively.
ribosomes and proteasomes
ribosomes and lysosomes
proteases and lysosomes
proteases and proteasomes
ribosomes and mRNA

If glucose was not phosphorylated in the first few reactions of glycolysis which of the following would occur?
The reactions in glycolysis following the phosphorylation would not be exergonic.
The reactions in glycolysis following the phosphorylation would not be endergonic.
Too much energy would be produced by glycolysis.
Fermentation would occur to produce NADH.
Fermentation would occur to produce pyruvate.

When acetyl-CoA containing radioactively labeled carbon atoms is fed to cells, the CO2 produced is not initially radioactive. However, molecules of citrate and oxaloacetate are radioactive. Only after some time has passed will radioactive CO2 released. What is the best explanation for this observation?
Acetyl groups are not metabolized directly into CO2, but enter a cyclical metabolic pathway.
Acetyl groups are not metabolized directly into CO2, but enter a linear metabolic pathway.
Acetyl groups are metabolized directly into CO2.
Acetyl groups first combine with citrate and oxaloacetate before being metabolized into CO2.

When a molecule of NAD+ gains a hydrogen atom, the molecule becomes reduced.
True
False

Which of the following statements is TRUE of both aerobic and anaerobic respiration?
Both use glycolysis to oxidize glucose to pyruvate.
Both produce NADH as high-energy intermediates.
Both produce either lactic acid or ethanol as a biproduct.
Both use glycolysis to oxidize glucose to pyruvate and both produce NADH as high-energy intermediates.
Both produce NADH as high-energy intermediates and both produce either lactic acid or ethanol as a bioproduct.

Which of the following are the final by-products of glucose oxidation during aerobic cell respiration?
ATP only
heat only
carbon dioxide only
both ATP and heat only
ATP, heat, and carbon dioxide

Energy released by the electron transport chain is used to pump H+ ions into which location?
cytosol
mitochondrial outer membrane
mitochondrial inner membrane
mitochondrial intermembrane space
mitochondrial matrix

Which of the following processes will occur in the presence or absence of oxygen?
glycolysis
electron transport chain
oxidative phosphorylation
cellular respiration
citric acid cycle

Which of the following statements is true?
The citric acid cycle occurs in the mitochondria matrix.
Glycolysis occurs in the mitochondria inner membrane.
Oxidative phosphorylation occurs in the mitochondria matrix.
The citric acid cycle occurs in the cytosol.
Electron transport chain and ATP synthase are in the cytosol.

What would you predict about a reaction that has a ΔG 0?
The reaction will require energy.
The reaction will yield energy.
The reaction is spontaneous.
The reaction will require energy and is spontaneous.
The reaction will yield energy and is spontaneous.

In a PET scan a patient is injected with radioactively labeled glucose. Why would cancer cells take up more of the radioactive glucose than surrounding non-cancerous tissues?
Because the produce more enzymes found in glycolysis.
Because they require more oxygen to metabolize glucose.
Because they are more sensitive to radiation.
Because they are less sensitive to radiation.
Because they rely more on oxidative phosphorylation than glycolysis to produce ATP

In prokaryotic cells, the electron transport system occurs in the mitochondria.
True
False

Where are the protein complexes associated with the electron transport chain located?
mitochondrial matrix
mitochondrial membrane
mitochondrial inner membrane
mitochondrial intermembrane space
cytosol

The enzyme responsible for converting pyruvate to acetyl CoA is called
pyruvate oxidase
pyruvate dehydrogenase.
hexokinase
ATP synthase.
peptidase.

Cellular respiration produces the most energy in the form of ATP from which of the following?
production of lactate
the citric acid cycle
substrate-level phosphorylation
glycolysis
oxidative phosphorylation

During glycolysis, glucose is broken down into
acetyl CoA.
NADH.
pyruvate.
oxygen.
ATP.

Fermentation is a more efficient form of energy production than aerobic respiration.
True
False

How can a living cell increase the rate of a chemical reaction?
By raising the temperature.
By raising the pH of the cytoplasm.
By lowering the pH of the cytoplasm.
By using a catalyst.
By increasing the entropy of the reactants.

The reaction: pyruvate + CoA + NAD+ → acetyl CoA + CO2 + NADH, is catalyzed by pyruvate dehydrogenase. If an inhibitor of this enzyme was added to cells ___ levels in the cytoplasm would increase.
Pyruvate
Acetyl CoA
NAD+
CoA

If oxygen is present, pyruvate will be converted to acetyl CoA in the mitochondrial matrix.
True
False

In the citric acid cycle, malate is oxidized to form
fumarate.
succinate.
citrate.
malate.
oxaloacetate.

The electron transport chain consists of a series of redox reactions in which electrons are transferred to oxygen as the final electron acceptor.
True
False

Which compound has the highest free energy and produces the most ATP per molecule when oxidized?
acetyl CoA
glucose
pyruvate
carbon
lactate

If you measure the air a person inhales you observe that the concentrations ______ in the air they exhale.
of O2 falls and CO2 rises
of O2 rises and CO2 falls
of both O2 and CO2 rise
of both O2 and CO2 fall

In the citric acid cycle, succinate is oxidized to form
fumarate.
succinate.
citrate.
malate.
oxaloacetate.