Chapter 19, Problem 4P

(a)

Summary Introduction

To predict:

The state of oxidation of ubiquinone, cytochrome b, c₁, c, and $\text{a}+{\text{a}}_{\text{3}}$ when NADH (nicotinamide adenine dinucleotide) and O₂ (oxygen) are abundant, but cyanide is added.

Introduction:

The conditions of environment determine the degree of reduction of carriers in respiratory chain. When there is an abundance of NADH and O₂ in the mitochondrion then, there is a decrease in steady state degree of reduction is observed. As the electron transfer is blocked, the electron carriers before the block become more reduced.

(b)

Summary Introduction

To predict:

The state of oxidation of ubiquinone, cytochrome b, c₁, c, and $\text{a}+{\text{a}}_{\text{3}}$ when NADH is abundant, but O₂ is exhausted.

Introduction:

O₂ is the terminal electron acceptor in the electron transport chain and NADH is the primary electron carrier. NADH transfers its electron to complex I thereby getting oxidized and reducing complex I.

(c)

Summary Introduction

To predict:

The state of oxidation of ubiquinone, cytochrome b, c₁, c, and $\text{a}+{\text{a}}_{\text{3}}$ O₂ is abundant but when NADH is exhausted.

Introduction:

When there is an abundance of NADH and O₂ in the mitochondrion then, there is a decrease in steady state degree of reduction is observed. As the electron transfer is blocked, the electron carriers before the block become more reduced.

(d)

Summary Introduction

To predict:

The state of oxidation of ubiquinone, cytochrome b, c₁, c, and $\text{a}+{\text{a}}_{\text{3}}$ when both NADH and O₂ are abundant.

Introduction:

Electron transport chain is the series of electron carriers. NADH transfers its electron to first complex and then complex I transfer electron to the next electron carrier. The terminal acceptor of electron is oxygen.