Biochemistry 2280A Study Guide - Mitochondrial Matrix, Atp Synthase, Electrochemical Gradient

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greenmoose117

5 May 2014

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The electron transport chain pumps protons out of the mitochondrial matrix. As a result, under normal conditions the proton concentration in the intermembrane space is about. 10-fold higher than the concentration in the matrix. Furthermore, excess positive charge builds up on the outer surface of the inner mitochondrial membrane, because the protons are not pumped with neutralizing counterions. The proton concentration gradient and the electrical potential combine to produce a protonmotive force that causes protons to flow back into the matrix if they are given the opportunity (fig 14-10, p. 462). This force is used to generate atp (fig 14-11, p. 462). Peter mitchell originally proposed that atp synthesis was driven by the flow of protons down an electrochemical gradient. Although not initially accepted by biochemists, his proposal, called the chemiosmotic hypothesis, best explained the experimental data (see p. 468-469). For example, it was observed that intact membranes are required for atp synthesis.

Related Questions

1. Compared to the generation of ATP by oxidative phosphorylation, what is a major difference in mechanism of ATP generation by substrate-level phosphorylation in glycolysis?

A. A proton gradient is not involved

B. The ATP produced has less energy content because oxygen was not involved.

C. Substrate level phosphorylation occurs in the inter-mitochondrial space

D. One can't generalize without knowing the substrate.

2. Which of the following statements is true?

A. Because the electrons in NADH are at a higher energy than the electrons in reduced ubiquinone, the NADH dehydrogenase complex can pump more protons than can the cytochrome b-c1 complex.

B.The pH in the mitochondrial matrix is higher than the pH in the intermembrane space.

C. The proton concentration gradient and the membrane potential across the inner mitochondrial membrane tend to work against each other in driving protons from the intermembrane space into the matrix.

D. The difference in proton concentration across the inner mitochondrial membrane has a much larger effect than the membrane potential on the total proton-motive force.

Oxidative phosphorylation questions - biochemistry (please be clear and don't copy/paste from google).

1. What is the function of a proton wire?

2. Describe Peter Mitchellâs mechanism for chemiosmotic coupling the energy of the transmembrane proton gradient to drive the endergonic process of ATP synthesis.

3. What transport proteins occur in the inner mitochondrial membrane? â¦.the outer mitochondrial membrane?

4. List the different types of redox centers in the respiratory electron transport chain. Which are one-electron carriers and which are two-electron carriers?

QUESTION 1

Which of the following is the correct order of the three stages of cellular respiration?

	a.	Krebs cycle, glycolysis, electron transport
	b.	electron transport, glycolysis, Krebs cycle
	c.	Krebs cycle, electron transport, glycolysis
	d.	glycolysis, Krebs cycle, electron transport
	e.	electron transport, Krebs cycle, glycolysis

1 points

QUESTION 2

Consider a bacterial cell that performs anaerobic respiration. If that bacterial cell had access to six molecules of glucose to use, how many ATP molecules would it be able to produce?

	a.	2
	b.	34
	c.	36
	d.	6
	e.	12

1 points

QUESTION 3

The oxygen that organisms need to live is used exclusively in which of the following metabolic pathways?

	a.	Electron transport chain
	b.	Anaerobic respiration
	c.	Glycolysis
	d.	Krebs cycle
	e.	ATP-Synthase

1 points

QUESTION 4

The electron transport chain uses the energy in NADH and FADH₂ to pump H⁺ ions from the matrix to the innermembrane space. The H⁺ gradient is then used to power ATP-Synthase. Enough H⁺ is pumped from the energy in a molecule of NADH to produce ______ ATP molecules, while enough H⁺ is pumped from the energy in a FADH₂ molecule to produce ______ ATP molecules.

	a.	three; two
	b.	three; three
	c.	two; two
	d.	two; three

1 points

QUESTION 5

Which of the following list contains only products of cellular respiration?

	a.	glucose, oxygen, ADP
	b.	ATP, carbon dioxide
	c.	oxygen, ADP, carbon dioxide
	d.	ATP, glucose, oxygen
	e.	glucose, ATP

1 points

QUESTION 6

What powers the enzyme ATP-Synthase?

	a.	NADH molecules
	b.	oxygen (O₂)
	c.	ATP
	d.	NADH and FADH₂ molecules
	e.	The H⁺ gradient between the matrix and inner-membrane space

1 points

QUESTION 7

Organisms exist which are able to survive using only glycolysis (i.e. without using oxidative phosphorylation).

True

False

1 points

QUESTION 8

Each ADP molecule contains ________ phosphates, and each ATP molecule contains ________ phosphates.

	a.	three; three
	b.	two; two
	c.	one; two
	d.	two; three
	e.	one; three

1 points

QUESTION 9

Adding a phosphate group to ADP to form ATP is an endergonic reaction.

True

False

1 points

QUESTION 10

The majority of ATP produced during cellular respiration is produced during glycolysis.

True

False

1 points

QUESTION 11

Glycolysis occurs:

	a.	on enzymes located in the inner-membrane.
	b.	in the cytosol.
	c.	in the inner-membrane space.
	d.	in the nucleus of the cell.
	e.	in the matrix of mitochondria.

1 points

QUESTION 12

Muscle soreness associated with strenuous exercise is due to:

	a.	the production of alcohol during anaerobic respiration.
	b.	a buildup of lactic acid.
	c.	an excessive amount of ATP that builds up during exercise.
	d.	the large amounts of CO₂ building up in the muscle.

1 points

QUESTION 13

A required reactant for glycolysis is:

	a.	the electron transport chain.
	b.	carbon dioxide.
	c.	oxygen.
	d.	NAD+.
	e.	mitochondria.

1 points

QUESTION 14

NADH is produced in all of the following except:

	a.	the electron transport chain.
	b.	the Krebs cycle.
	c.	glycolysis.

Biochemistry 2280A Study Guide - Mitochondrial Matrix, Atp Synthase, Electrochemical Gradient

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