Question 1

Which enzyme catalyzes the reduction of oxygen to water?

Accepted Answer

Cytochrome c oxidase is the enzyme responsible for catalyzing the reduction of oxygen to water in the electron transport chain, specifically in the process of cellular respiration.

Question 2

What term is used to describe an ATP-generating process in which an inorganic substance such as oxygen serves as the ultimate electron acceptor?

Accepted Answer

Respiration is the ATP-generating process where an inorganic substance, often oxygen, acts as the final electron acceptor in the electron transport chain, leading to the production of ATP through oxidative phosphorylation.

Question 3

What process allows cytoplasmic NADH to be reoxidized by O₂ using the electron-transport system?

Accepted Answer

The glycerol 3-phosphate shuttle and the malate-aspartate shuttle are both mechanisms that allow the transfer of electrons from cytoplasmic NADH into the mitochondria, where they can be used by the electron transport chain to generate ATP.

Question 4

Which enzyme transfers electrons from a membrane-soluble carrier to a water-soluble carrier in the electron-transport process?

Accepted Answer

Q-cytochrome c oxidoreductase (also known as Complex III in the electron transport chain) transfers electrons from the membrane-soluble carrier ubiquinone (Q) to the water-soluble carrier cytochrome c.

Question 5

What name is given to the hypothesis proposed by Peter Mitchell that explains how ATP synthesis is coupled to electron transport?

Accepted Answer

The chemiosmotic hypothesis, proposed by Peter Mitchell, explains how ATP synthesis is coupled to electron transport by creating a proton gradient across a membrane, which then drives ATP synthesis.

Question 6

The unequal distribution of H⁺ across the inner mitochondrial membrane creates a ________________ force.

Accepted Answer

The answer of The unequal distribution of H⁺ across the...

Question 7

In the initial step of Complex I, two high-potential electrons are transferred from NADH to the ___________ prosthetic group of this complex.

Accepted Answer

The answer of In the initial step of Complex I,...

Question 8

What type of enzyme plays a key role in apoptosis?

Accepted Answer

Caspases are a family of protease enzymes playing essential roles in programmed cell death (apoptosis).

Question 9

_______________ is a molecular assembly in the inner mitochondrial membrane that carries out the synthesis of ATP.

Accepted Answer

The answer of _______________ is a molecular assembly in the...

Question 10

_________________ is a poison because it blocks the flow of electrons from cytochrome c to oxygen.

Accepted Answer

The answer of _________________ is a poison because it blocks...

Question 11

Which of the citric acid cycle enzymes is also part of an electron-transport complex?

Accepted Answer

Succinate dehydrogenase is unique among the citric acid cycle enzymes because it is also a component of Complex II in the electron transport chain, directly participating in the transfer of electrons to the coenzyme Q (ubiquinone).

Question 12

Cytochrome c oxidase contains two heme A groups and three ______________ ions.

Accepted Answer

The answer of Cytochrome c oxidase contains two heme A...

Question 13

________________ carries electrons from Complex III to Complex IV.

Accepted Answer

The answer of ________________ carries electrons from Complex III to...

Question 14

In the glycerol phosphate shuttle, cytoplasmic glycerol phosphate dehydrogenase uses cytoplasmic NADH to reduce _________________ to glycerol-3-phosphate.

Accepted Answer

The answer of In the glycerol phosphate shuttle, cytoplasmic glycerol...

Question 15

The transfer of a single electron to O₂ forms the reactive _______________ ion.

Accepted Answer

The answer of The transfer of a single electron to...

Question 16

Acceptor control of oxidative phosphorylation means that the rate of respiration depends upon the level of __________.

Accepted Answer

The answer of Acceptor control of oxidative phosphorylation means that...

Question 17

Cytochrome ________ is the only water-soluble cytochrome of the electron-transport chain.

Accepted Answer

The answer of Cytochrome ________ is the only water-soluble cytochrome...

Question 18

What organelle is the site of oxidative phosphorylation in eukaryotes?

Accepted Answer

Oxidative phosphorylation, a part of cellular respiration that produces ATP, occurs in the mitochondria of eukaryotic cells.

Question 19

What prosthetic group is present in complexes I, II, and III of electron transport?

Accepted Answer

Iron-sulfur clusters are prosthetic groups present in complexes I, II, and III of the electron transport chain, playing a crucial role in electron transfer.

Question 20

What type of protein makes the outer mitochondrial membrane relatively permeable?

Accepted Answer

Porins are a type of protein that make the outer mitochondrial membrane relatively permeable by forming channels through which molecules can diffuse.

Quiz 18: Oxidative Phosphorylation