Lesson test: Breathing with a gradient

Sign in

Libre University uses your GitHub account. Signing in is only needed to sit a final test, so the score is kept on your profile.

Breathing with a gradient

1.[2p]
What is the citric acid cycle's main product, judged by what the cell does with it?

Reduced electron carriers, since the cycle makes only one GTP per turn

Correct

ATP, made directly at four points in the cycle

The answer is: Reduced electron carriers, since the cycle makes only one GTP per turn

Acetyl-CoA, which is regenerated each turn

The answer is: Reduced electron carriers, since the cycle makes only one GTP per turn

Oxygen, released as the carbon is stripped

The answer is: Reduced electron carriers, since the cycle makes only one GTP per turn

2.[3p]
Electrons falling from NADH at $- 0.32$ V to oxygen at $+ 0.82$ V give $Δ G = - n F Δ E$ with $n = 2$ and $F = 96485$ C/mol. What is $Δ G$ in kJ/mol? Give a negative number.

CorrectNot quite: -220

3.[1p]
Oxygen's role in respiration is to act as the terminal electron acceptor at the end of the chain.

True

Correct

False

The answer is: True

4.[3p]
Jagendorf and Uribe soaked thylakoid membranes at pH 4, jumped the outside to pH 8 in the dark, and got ATP. Why did this matter?

A pH difference alone was sufficient, which no chemical intermediate theory can explain

Correct

It showed that light is required for ATP synthesis

The answer is: A pH difference alone was sufficient, which no chemical intermediate theory can explain

It showed that ATP synthase is a chemical rather than a mechanical enzyme

The answer is: A pH difference alone was sufficient, which no chemical intermediate theory can explain

It measured the number of protons per ATP

The answer is: A pH difference alone was sufficient, which no chemical intermediate theory can explain

5.[3p]
Racker and Stoeckenius put bacteriorhodopsin from an archaeon and ATP synthase from cow heart into the same artificial vesicle. What did the result establish?

That nothing links the two proteins except the proton gradient between them

Correct

That the two proteins bind each other directly

The answer is: That nothing links the two proteins except the proton gradient between them

That ATP synthase can be driven by light

The answer is: That nothing links the two proteins except the proton gradient between them

That archaea and cattle share a recent ancestor

The answer is: That nothing links the two proteins except the proton gradient between them

6.[3p]
Match each figure in oxidative phosphorylation to its value.

Protons pumped per NADH
Protons pumped per FADH₂
Proton-motive force
Protons per ATP made and exported
ATP per glucose, all routes counted

about 4
about 6
about 200 mV
about 10
about 30

Show the answer

Protons pumped per NADH: about 10 Protons pumped per FADH₂: about 6 Proton-motive force: about 200 mV Protons per ATP made and exported: about 4 ATP per glucose, all routes counted: about 30

7.[3p]
Why is the ATP yield per glucose not a whole number?

Select all that apply

The number of protons pumped and the number the synthase uses are set by separate machinery

Correct

The rotor ring of ATP synthase has a subunit count that need not divide the protons pumped

Correct

Some of the gradient leaks back across the inner membrane

Correct

Because the citric acid cycle turns a non-integral number of times

The answer is: The number of protons pumped and the number the synthase uses are set by separate machinery, The rotor ring of ATP synthase has a subunit count that need not divide the protons pumped, Some of the gradient leaks back across the inner membrane

8.[2p]
2,4-dinitrophenol carries protons across the inner membrane without passing through ATP synthase. What does a cell treated with it do?

Consumes oxygen faster than ever while making no ATP, releasing the energy as heat

Correct

Stops consuming oxygen and makes no ATP

The answer is: Consumes oxygen faster than ever while making no ATP, releasing the energy as heat

Consumes oxygen normally and makes more ATP than usual

The answer is: Consumes oxygen faster than ever while making no ATP, releasing the energy as heat

Reverses the electron transport chain

The answer is: Consumes oxygen faster than ever while making no ATP, releasing the energy as heat

9.[2p]
UCP1 in brown fat is evidence for chemiosmosis, because a single protein that only conducts protons converts a mitochondrion into a heater.

True

Correct

False

The answer is: True

1.[2p] What is the citric acid cycle's main product, judged by what the cell does with it?

2.[3p] Electrons falling from NADH at -0.32 V to oxygen at +0.82 V give ΔG=-nFΔE with n=2 and F=96485 C/mol. What is ΔG in kJ/mol? Give a negative number.

3.[1p] Oxygen's role in respiration is to act as the terminal electron acceptor at the end of the chain.

4.[3p] Jagendorf and Uribe soaked thylakoid membranes at pH 4, jumped the outside to pH 8 in the dark, and got ATP. Why did this matter?

5.[3p] Racker and Stoeckenius put bacteriorhodopsin from an archaeon and ATP synthase from cow heart into the same artificial vesicle. What did the result establish?

6.[3p] Match each figure in oxidative phosphorylation to its value.

7.[3p] Why is the ATP yield per glucose not a whole number?

8.[2p] 2,4-dinitrophenol carries protons across the inner membrane without passing through ATP synthase. What does a cell treated with it do?

9.[2p] UCP1 in brown fat is evidence for chemiosmosis, because a single protein that only conducts protons converts a mitochondrion into a heater.

1.[2p]
What is the citric acid cycle's main product, judged by what the cell does with it?

2.[3p]
Electrons falling from NADH at $- 0.32$ V to oxygen at $+ 0.82$ V give $Δ G = - n F Δ E$ with $n = 2$ and $F = 96485$ C/mol. What is $Δ G$ in kJ/mol? Give a negative number.

3.[1p]
Oxygen's role in respiration is to act as the terminal electron acceptor at the end of the chain.

4.[3p]
Jagendorf and Uribe soaked thylakoid membranes at pH 4, jumped the outside to pH 8 in the dark, and got ATP. Why did this matter?

5.[3p]
Racker and Stoeckenius put bacteriorhodopsin from an archaeon and ATP synthase from cow heart into the same artificial vesicle. What did the result establish?

6.[3p]
Match each figure in oxidative phosphorylation to its value.

7.[3p]
Why is the ATP yield per glucose not a whole number?

8.[2p]
2,4-dinitrophenol carries protons across the inner membrane without passing through ATP synthase. What does a cell treated with it do?

9.[2p]
UCP1 in brown fat is evidence for chemiosmosis, because a single protein that only conducts protons converts a mitochondrion into a heater.