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19 Jan 2019

Identify the electron transport complex for each of these:

a) This complex transfers electrons to molecular oxygen

b) This complex transfers electrons to a heme group in cytochrome C

c) This complex accepts electrons from reduced ubiquinone

d) This complex is not active in electron transport if the electrons were delivered by FADH2

e) This complex only transfers electrons, but does not pump protons

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7 Feb 2023

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Deanna HettingerLv2

21 Jan 2019

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Related questions

19. Which of the following is a component of Succinate dehydrogenase in Electron transport chain?

A. Niacin

B. FMN

C. FAD

D. Coenzyme Q

E. Lipoic acid

20. In electron transport the flow of electrons:

A. is bidirectional

B. goes from a high energy state to a low energy state

C. takes place in the outer mitochondrial membrane

D. are used to pump H+ into the mitochondrial matrix

21. Which of the following statements about the electron transport chain is NOT correct

A. It is located in the inner mitochondrion membrane

B. Cytochrome c accepts electrons from complex II

C. Cytochrome c oxidase (complex IV) accepts electrons from Cytochrome c

D. Complex I is called NADH dehydrogenase

E. Coenzyme Q accepts electrons from complex I and complex II

22. In the electron transport chain, the enzyme cytochrome C oxidase:

A. Uses H2O as a substrate

B. Produces HOOH as a product

C. Cannot function if oxygen is absent

D. Accepts electrons from hydrogen ions

E. Uses ADP and Pi as substrates

Can you answer the following questions:

1. Carbon monoxide is considered toxic because it acts on Complex IV. How would the addition of carbon monoxide to actively respiring mitochondria affect the relative oxidation-reduction states of all components of the electron-transport chain?

A) All four complexes would remain oxidized because they function as a multisystem complex.

B) Complexes I and III would be reduced, but complexes II and IV would be oxidized because the

electrons come from FADH2 oxidation, not NADH.

C) Complexes I, II, and III would be oxidized but Complex IV would remain reduced.

D) Complexes I, II, and III would be reduced and Complex IV would be oxidized.

E) All four complexes would remain reduced because they function as a multisystem complex.

2. Electrons are not very soluble in hydrophobic environments such as a bilipid membrane. What evidence is there that electrons move from complex to complex through the lipid membrane?

A) Cytochrome C is the electron carrier in the membrane and undergoes a head-over-heel flip to set up the proton gradient.

B) Cytochrome C is the electron carrier in the membrane and contains a cydrophoric porphyrin center.

C) CoQ is the electron carrier within the membrane and seems to be confined to the respirasome.

D) CoQ is the electron carrier within the membrane and it contains a hydrophobic porphyrin center.

E) FeS clusters are the carriers within the membrane and the electrons move from one cluster to the

next in a chain-like fashion.

3. What is the rationale for saying that âelectrons flow down the electron-transport chainâ?

A) Electrons flow from oxidized carriers to reduced carriers in discrete steps like a staircase.

B) Electrons flow from half-reactions with more positive redox potentials to more negative.

C) Electrons flow from reactions that continuously generate negative free energy values.

D) Electrons flow from the outer surface to the inner surface, a top down perception.

E) Because we think of electrons flowing like a liquid, the only direction electrons can flow is down.

(BIOCHEMISTRY QUESTION) Rotenone is a poison that acts by blocking electron flow in Complex I. Predict the effect of Rotenone on the following processes(for a)-d) you can simply state "up" or "down"): a) O2 utilization (up or down). b. ATP production(up or down). c. NADH levels (up or down). d, TCA cycle (inhibited or running). e. Finally, even after several hours of rotenone inhibition, will complex II continue to pass electrons from succinate to FAD (making FADH2) and finally ubiquinone? Why or why not?

MY RESPONSES -- could you review and let me know if they are correct? If not, could you provide the correct response with an explanation?

a. down

b. down

c. up, d. inhibited

e. no inhibition of complex leads to NADH accumulation, that leads to the inhibition of the citric acid cycle. If this cycle is inhibited then the production of succinate, the initial electron donor for complex II, will also be inhibited and thus complex II will no longer receive electrons in order to continue an electron transport.