Chapter 25, Problem 25.112EP

(a)

Interpretation Introduction

Interpretation:

Electron transport chain occurs within mitochondria of a cell or in a cell’s cytosol has to be indicated.

Concept introduction:

Electron transfer chain is defined as a series of biochemical reactions in which the electrons and hydrogen ions obtained from NADH and FADH₂ react with molecular oxygen to produce water. NADH and FADH₂ are oxidized through redox reactions.  The table to represent the molecule of ATP produced by the oxidation of one molecule of NADH and FADH₂ in the electron transfer chain is as follows:

$\begin{array}{cc}\text{NADH}& \text{3ATP}\\ {\text{FADH}}_{\text{2}}& \text{2ATP}\end{array}$

(b)

Interpretation Introduction

Interpretation:

Lipogenesis occurs within mitochondria of a cell or in a cell’s cytosol has to be indicated.

Concept introduction:

Lipogenesis is the process employed for the synthesis of fatty acid. The starting precursor for the synthesis is acetyl CoA. The enzyme employed for the process is fatty acid synthase. It is a multienzyme complex that ties the reaction responsible for the synthesis of fatty acid. This process is the reverse of the degradation of fatty acid.

(c)

Interpretation Introduction

Interpretation:

Glycerol metabolism occurs within mitochondria of a cell or in a cell’s cytosol has to be indicated.

Concept introduction:

Triacylglycerol mobilization is an ongoing process in which triacylglycerols that are stored in the adipose tissue are hydrolyzed. Fatty acids and glycerol are the products of triacylglycerol mobilization. The products are released into the bloodstream.

After entering the bloodstream, the glycerol travels to the kidneys or liver. The first stage of glycerol metabolism occurs in the liver or kidney where it is converted to $\text{dihydroxyacetone phosphate}$. After the first stage, the remaining stages of glycerol metabolism are the same as glucose pathways. The overall equation for glycerol metabolism is as follows:

$\text{Glycerol}+\text{ATP}+{\text{NAD}}^{+}\to \text{Dihydroxyacetone phosphate}+\text{ADP}+\text{NADH}+{\text{H}}^{+}$

(d)

Interpretation Introduction

Interpretation:

Gluconeogenesis occurs within mitochondria of a cell or in a cell’s cytosol has to be indicated.

Concept introduction:

Gluconeogenesis is an eleven-step pathway in which glucose is produced from non-carbohydrate substances. The net overall equation for gluconeogenesis is as follows:

$2\text{Pyruvate}+2\text{NADH}+4\text{ATP}+2\text{GTP}+2{\text{H}}_2\text{O}\to \text{Glucose}+4\text{ADP}+2\text{GDP}+6{\text{P}}_{\text{i}}+2{\text{NAD}}^{+}$