Becker's-World-Of-The-Cell. Chapter 10. Introduction

Cellular Respiration

The oxidation driven flow of electrons through or within a membrane from reduced co-enzymes to electron acceptors, usually accompanied by the generation of ATP.

Ultimate Electron Acceptor

Oxygen

Reduced form of oxygen?

Water (H2O)

End products of Aerobic Repiration

CO2 and H2O

Carbon dioxide and Water

Aerobic respiration can be considered in 4 stages

Stage 1: Glycolysis

Stage 2 : Citric Acid Cycle

Stage 3 : Electron transport System

Stage 4 : ATP Synthesis

Stage 1-

Glycolysis

Glycolytic Pathway.

Glucose oxidises to Pyruvate.

Takes Place in Cytosol (Cytoplasm of cell).

Glycolysis Products?

2 ATP, 2 NADH, and 2 Pyruvate molecules

After stage 1, before stage 2,

The Bridge Reaction

Takes place between cytoplasm and mitochondria

Converts 2 Pyruvate to 2 Acetyl Co-enzyme A

Bridge reaction Products

2 NADH and 2 CoA from 2 Pyruvate

Stage 2 -

Tricarboxylic Acid Cycle (TCA)

Krebs Cycle

Citric Acid Cycle

Substrate for TCA is Acetyl CoA (x2)

Products of TCA

2 ATP

6 NADH

2 FADH2

All this for 2 molecules of Acetyl CoA

(From 1 Glucose)

Stage 3-

Electron Transport System (ETS)

Takes place in Mitochondrial membrane.

Transfer of electrons from reduced co-enzymes to oxygen.

Coupled to pumping of protons across membranes.

Creates electrochemical proton gradient

Products of ETS

Takes 10 NADH and 2 FADH2 per Glucose molecule

Uses Proton Pumping.

Gives 34 ATP and 10 NAD+ and 2 FAD

Stage 4- ATP Synthesis

The energy of the proton gradient is used to drive ATP Synthesis.

This ATP Synthesis is called Oxidative Phosphorylation.

Where does ATP Synthesis occur

The F0 is in Inner mitochondrial membrane, the F1 is jutting out to the mitochondrial matrix.

Total Result is 36 or 38 ATP .