Question 1

The presence of Ca2+ ion transport molecules in the inner mitochondrial membrane is consistent with the mitochondrion's role in _______.

Accepted Answer

A)  muscle contraction
B)  regulating cytosolic Ca2+ ion concentration
C)  ATP manufacture
D)  ADP manufacture
E)  control of membrane fusionF) All of the above
G) B) and D)

Question 2

What are the structural features of electron-transport complexes that allow them to function as proton pumps?

Accepted Answer

The free energy that is released as elec...

Question 3

Which mitochondrial genes when mutated or experiencing deletions cause the most serious disorders?

Accepted Answer

Mutations or deletions in the genes enco...

Question 4

Mitochondria are sites of the __________.

Accepted Answer

A)  synthesis of certain amino acids
B)  synthesis of heme groups
C)  uptake of Ca2+ ions
D)  release of Ca2+ ions
E)  All of these are correct.F) D) and E)
G) A) and E)

Question 5

What causes Zellweger's syndrome? What do the peroxisomes of ZS patients look like?

Accepted Answer

Peroxisomes in Zellweger's syndrome pati...

Question 6

Where are most of the enzymes of the Krebs cycle located?

Accepted Answer

A)  in the intercristal space
B)  on the cristae
C)  on the ribosomes
D)  in the soluble phase of the mitochondrial matrix
E)  in the intermembrane spaceF) B) and D)
G) None of the above

Question 7

How do many potent respiratory poisons exert their effect?

Accepted Answer

A)  They break down oxygen.
B)  They bind to electrons.
C)  They bind to the cytochrome oxidase catalytic site.
D)  They bind to oxygen.
E)  They denature the inner mitochondrial membrane.F) A) and C)
G) B) and C)

Question 8

What energy source other than ATP hydrolysis do mitochondria,unlike most other organelles,routinely use to power their activities?

Accepted Answer

A)  ADP hydrolysis
B)  proton-motive force
C)  Na+ ion gradient
D)  K+ ion gradient
E)  Ca2+ gradientF) A) and D)
G) C) and D)

Question 9

Which activity below is not thought to be driven by the proton-motive force?

Accepted Answer

A)  formation of the spindle
B)  ADP and inorganic phosphate uptake into the mitochondrion in exchange for ATP and H+,respectively
C)  uptake of Ca2+ ions into the mitochondrion
D)  the events of mitochondrial fusion
E)  uptake of specifically targeted proteins into the mitochondrion from the matrixF) C) and E)
G) B) and D)

Question 10

What properties do mitochondria and peroxisomes have in common?

Accepted Answer

They both form by splitting from preexis...

Question 11

Why must the process by which cytochrome oxidase works be efficient?

Accepted Answer

A)  If it is not,mitochondria will shrink.
B)  If it is not,mitochondria will swell and burst.
C)  The process deals with very dangerous substances,which,if released,could damage virtually every cell macromolecule.
D)  If it is not the mitochondria could denature.
E)  All of these are correct.F) C) and E)
G) A) and E)

Question 12

A preparation of submitochondrial particles is made.The particles are able to oxidize substrates,generate a proton gradient and make ATP.If the particles are treated with urea,what happens? If DNP is added,what happens? How does DNP make the inner mitochondrial membrane permeable to protons?

Accepted Answer

Urea treatment removes the F1 spheres from ATP synthase.As a result,the membrane is no longer able to maintain the proton gradient.Protons leak out of the F0 base piece in an uncontrolled fashion when the headpiece is removed and ATP cannot be made because the headpiece that makes it is gone.DNP also uncouples ATP production from electron transport.It causes the membrane to become permeable to protons and thus dissipates the proton gradient,making ATP production by ATP synthase impossible.DNP combines with protons and,because of its lipid solubility,carries the protons across the inner mitochondrial membrane down their electrochemical gradient.

Question 13

Observations of two different cell types indicate a couple of differences in their mitochondria.Cell type 1 has 2-3 times the mitochondria of Cell Type 2.The mitochondria in Cell Type 1 are also larger,contain more cristae and the cristae extend farther across the mitochondria than in Cell Type 2.Which cell type is likely to have more extensive energy requirements?

Accepted Answer

Since ATP synthase is located on the cri...

Question 14

You treat some cells with DNP and discover that ATP production ceases.Upon closer examination,you also note that the number of calcium ions sequestered in the mitochondrion decreases.Please explain.

Accepted Answer

DNP dissipates the proton gradient gener...

Question 15

What happens to the mtDNA of mice that are homozygous for the mutant gene called Polg? How do the "mutator" mice differ from their normal littermates? How do mice that are heterozygous for the Polg mutation differ from those that are homozygous for the Polg mutation? What should have happened to the life span of mice heterozygous for the Polg gene,if mtDNA mutations were a major contributor to the normal aging process? What do the above results of studies of the Polg mutation suggest about the relationship between mtDNA mutations and premature aging in animals?

Accepted Answer

The Polg gene encodes the enzyme that re...

Question 16

How is the energy used to make ATP via the electron transport chain generated?

Accepted Answer

A)  The energy from electrons bound to reduced coenzymes is used to create a steep electrochemical gradient.
B)  Electrons bound to NADH are used to generate a H+ ion gradient across the inner mitochondrial membrane.
C)  Electrons bound to FADH2 are used to generate a proton gradient across the inner mitochondrial membrane.
D)  Electrons bound to NADH are used to generate a proton gradient across the inner mitochondrial membrane.
E)  All of these are correct.F) D) and E)
G) B) and D)

Question 17

When fission of mitochondria becomes more frequent than fusion,the mitochondria tend to become __________.

Accepted Answer

A)  more elongated
B)  more interconnected
C)  more numerous
D)  more distinct
E)  more numerous and more distinctF) A) and E)
G) A) and D)

Question 18

A patient who has abnormal mitochondria has the following symptoms: long-term fatigue and muscle weakness,elevated metabolic rate and body temperature.Studies indicate that the mitochondria have been released from their normal respiratory control.How does this explain the elevated temperature? Why are most disorders that have been traced to mitochondrial dysfunction characterized by degeneration of muscle or brain tissue? What are the characteristics of some of the conditions that result from dysfunctional mitochondria?

Accepted Answer

If the cells run at an abnormally high m...

Question 19

___________ exhibit lower electron affinity.

Accepted Answer

A)  Strong oxidizing agents
B)  Strong elucidating agents
C)  Strong reducing agents
D)  Weak reducing agents
E)  Weak eliminating agentsF) All of the above
G) A) and B) C

Question 20

Why does the DNA in mitochondria exhibit about 10 times the mutation rate seen in nuclear DNA and what is the possible effect of this on disease processes?

Accepted Answer

Because of its proximity to electron-transport processes,which lead to the release of mutagenic oxygen radicals,mtDNA is thought to come under a much greater level of attack than nuclear DNA.In addition,nuclear DNA is better protected from persistent damage by the presence of a greater variety of DNA repair systems.Thus,damage inflicted upon nuclear DNA can be repaired,while damage to mitochondrial DNA cannot be repaired as effectively.These factors explain the greater than 10-fold higher mutation rate of mtDNA.Thus,mutations are particularly likely to accumulate in the mitochondria of cells that remain in the body for long periods of time (nerves and muscle tissue).The degenerative changes in mitochondrial functions are thought to contribute to a number of common neurological diseases with adult-onset,most notably Parkinson's disease (PD).

Exam 5: Aerobic Respiration and the Mitochondrion

The presence of Ca²⁺ ion transport molecules in the inner mitochondrial membrane is consistent with the mitochondrion's role in _______.

Correct Answer
verified

What are the structural features of electron-transport complexes that allow them to function as proton pumps?

Correct Answer
verified
The free energy that is released as elec...
View Answer

Which mitochondrial genes when mutated or experiencing deletions cause the most serious disorders?

Correct Answer
verified
Mutations or deletions in the genes enco...
View Answer

Mitochondria are sites of the __________.

Correct Answer
verified

What causes Zellweger's syndrome? What do the peroxisomes of ZS patients look like?

Correct Answer
verified
Peroxisomes in Zellweger's syndrome pati...
View Answer

Where are most of the enzymes of the Krebs cycle located?

Correct Answer
verified

How do many potent respiratory poisons exert their effect?

Correct Answer
verified

What energy source other than ATP hydrolysis do mitochondria,unlike most other organelles,routinely use to power their activities?

Correct Answer
verified

Which activity below is not thought to be driven by the proton-motive force?

Correct Answer
verified

What properties do mitochondria and peroxisomes have in common?

Correct Answer
verified
They both form by splitting from preexis...
View Answer

Why must the process by which cytochrome oxidase works be efficient?

Correct Answer
verified

A preparation of submitochondrial particles is made.The particles are able to oxidize substrates,generate a proton gradient and make ATP.If the particles are treated with urea,what happens? If DNP is added,what happens? How does DNP make the inner mitochondrial membrane permeable to protons?

Correct Answer
verified
Since ATP synthase is located on the cri...
View Answer

You treat some cells with DNP and discover that ATP production ceases.Upon closer examination,you also note that the number of calcium ions sequestered in the mitochondrion decreases.Please explain.

Correct Answer
verified
DNP dissipates the proton gradient gener...
View Answer

Correct Answer
verified
The Polg gene encodes the enzyme that re...
View Answer

How is the energy used to make ATP via the electron transport chain generated?

Correct Answer
verified

When fission of mitochondria becomes more frequent than fusion,the mitochondria tend to become __________.

Correct Answer
verified

Correct Answer
verified
If the cells run at an abnormally high m...
View Answer

___________ exhibit lower electron affinity.

Correct Answer
verified
C

Why does the DNA in mitochondria exhibit about 10 times the mutation rate seen in nuclear DNA and what is the possible effect of this on disease processes?

Exam 5: Aerobic Respiration and the Mitochondrion

The presence of Ca2+ ion transport molecules in the inner mitochondrial membrane is consistent with the mitochondrion's role in _______.

Correct AnswerverifiedShow Answer

What are the structural features of electron-transport complexes that allow them to function as proton pumps?

Correct AnswerverifiedThe free energy that is released as elec...View AnswerShow Answer

Which mitochondrial genes when mutated or experiencing deletions cause the most serious disorders?

Correct AnswerverifiedMutations or deletions in the genes enco...View AnswerShow Answer

Mitochondria are sites of the __________.

Correct AnswerverifiedShow Answer

What causes Zellweger's syndrome? What do the peroxisomes of ZS patients look like?

Correct AnswerverifiedPeroxisomes in Zellweger's syndrome pati...View AnswerShow Answer

Where are most of the enzymes of the Krebs cycle located?

Correct AnswerverifiedShow Answer

How do many potent respiratory poisons exert their effect?

Correct AnswerverifiedShow Answer

What energy source other than ATP hydrolysis do mitochondria,unlike most other organelles,routinely use to power their activities?

Correct AnswerverifiedShow Answer

Which activity below is not thought to be driven by the proton-motive force?

Correct AnswerverifiedShow Answer

What properties do mitochondria and peroxisomes have in common?

Correct AnswerverifiedThey both form by splitting from preexis...View AnswerShow Answer

Why must the process by which cytochrome oxidase works be efficient?

Correct AnswerverifiedShow Answer

A preparation of submitochondrial particles is made.The particles are able to oxidize substrates,generate a proton gradient and make ATP.If the particles are treated with urea,what happens? If DNP is added,what happens? How does DNP make the inner mitochondrial membrane permeable to protons?

Correct AnswerverifiedSince ATP synthase is located on the cri...View AnswerShow Answer

You treat some cells with DNP and discover that ATP production ceases.Upon closer examination,you also note that the number of calcium ions sequestered in the mitochondrion decreases.Please explain.

Correct AnswerverifiedDNP dissipates the proton gradient gener...View AnswerShow Answer

Correct AnswerverifiedThe Polg gene encodes the enzyme that re...View AnswerShow Answer

How is the energy used to make ATP via the electron transport chain generated?

Correct AnswerverifiedShow Answer

When fission of mitochondria becomes more frequent than fusion,the mitochondria tend to become __________.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedIf the cells run at an abnormally high m...View AnswerShow Answer

___________ exhibit lower electron affinity.

Correct AnswerverifiedC

Why does the DNA in mitochondria exhibit about 10 times the mutation rate seen in nuclear DNA and what is the possible effect of this on disease processes?

The presence of Ca²⁺ ion transport molecules in the inner mitochondrial membrane is consistent with the mitochondrion's role in _______.

Correct Answer
verified

Correct Answer
verified
The free energy that is released as elec...
View Answer

Correct Answer
verified
Mutations or deletions in the genes enco...
View Answer

Correct Answer
verified

Correct Answer
verified
Peroxisomes in Zellweger's syndrome pati...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
They both form by splitting from preexis...
View Answer

Correct Answer
verified

Correct Answer
verified
Since ATP synthase is located on the cri...
View Answer

Correct Answer
verified
DNP dissipates the proton gradient gener...
View Answer

Correct Answer
verified
The Polg gene encodes the enzyme that re...
View Answer

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
If the cells run at an abnormally high m...
View Answer

Correct Answer
verified
C