Chapter 23, Problem 23.122EP

(a)

Interpretation Introduction

Interpretation: To identify the step of the citric acid cycle in that ATP-precursor-molecule is generated that enter the ETC at enzyme complex I.

Concept introduction: Citric acid cycle is the third stage of the biochemical energy production process. The cycle includes the reactions in which the acetyl part of acetyl CoA is oxidized and leads to the formation of carbon dioxide and $\text{CoA-SH}$.

Electron transport chain is a sequence of biochemical reactions in which electrons and hydrogen atoms from the citric acid cycle are transferred to various intermediate carriers and finally reacts with molecular oxygen to form a water molecule. The reaction of the formation of the water is:

${\text{O}}_2+4{\text{e}}^{-}+4{\text{H}}^{+}\to 2{\text{H}}_{\text{2}}\text{O}$

The electron transport chain is as follows:

NADH is the reduced form of nicotinamide adenine dinucleotide. It is employed as an oxidizing agent in various reactions like oxidation of secondary alcohol into a ketone. Its structure consists of three subunits: nicotinamide, ribose, and ADP.

(b)

Interpretation Introduction

Interpretation: To identify the step of the citric acid cycle in that ATP-precursor-molecule is generated that enter the ETC at enzyme complex II.

Concept introduction: Citric acid cycle is the third stage of the biochemical energy production process. The cycle includes the reactions in which the acetyl part of acetyl CoA is oxidized and leads to the formation of carbon dioxide and $\text{CoA-SH}$.

Electron transport chain is a sequence of biochemical reactions in which electrons and hydrogen atoms from the citric acid cycle are transferred to various intermediate carriers and finally reacts with molecular oxygen to form a water molecule. The reaction of the formation of the water is:

${\text{O}}_2+4{\text{e}}^{-}+4{\text{H}}^{+}\to 2{\text{H}}_{\text{2}}\text{O}$

The electron transport chain is as follows:

FADH₂ is the reduced form of flavin adenine dinucleotide. The main function of flavin adenine dinucleotide is to act as an oxidizing agent and used by the cell in oxidation reactions like oxidation of fatty acid.

(c)

Interpretation Introduction

Interpretation: To identify the step of the citric acid cycle in that ATP-precursor-molecule is generated that does not enter the ETC.

Concept introduction: Citric acid cycle is the third stage of the biochemical energy production process. The cycle includes the reactions in which the acetyl part of acetyl CoA is oxidized and leads to the formation of carbon dioxide and $\text{CoA-SH}$.

Electron transport chain is a sequence of biochemical reactions in which electrons and hydrogen atoms from the citric acid cycle are transferred to various intermediate carriers and finally reacts with molecular oxygen to form a water molecule. The reaction of the formation of the water is:

${\text{O}}_2+4{\text{e}}^{-}+4{\text{H}}^{+}\to 2{\text{H}}_{\text{2}}\text{O}$

The electron transport chain is as follows: