Cellular Metabolism: Respiration (Anaerobic & Aerobic) .........

I). Definition

Metabolism: All of the chemical reactions necessary to maintain life.

Stage 1: Digestion in the GI tract.
Stage 2: Glycolysis: occurs in the cytoplasm.
Stage 3: Production of ATP in the mitochondria.

	anaerobic
	aerobic
	coenzyme: non-protein substances associated with an enzyme. In metabolism they act as electron acceptors.

NAD+-----------------> NADH+

FAD-----------> FADH+

II). Cellular Respiration (Oxidation of Glucose)

C6H12O6 + 6O2-----> 6H2O + 6CO2 + 36 ATP +heat

1). Glycolysis

Glucose------> 2 pruvic acids + 2 ATP

	Glycolysis occurs in the cytoplasm.
	Anaerobic reaction.
	No Oxygen .
	Release 2 ATP

2). Krebs Cycle

	The Krebs Cycle occurs in the mitochondria
	Aerobic reaction.
	Requires oxygen

2 Pruvic Acid -------> 6CO2 + 10 reduced coenzymes + 2 ATP

The Krebss cycle occurs twice per glucose molecule.

	6 carbon dioxides are released
	2 ATP.
	10 NAD coenzymes are reduced to NADH+.

3). Electron Transport Chain

NADH- à  FADH- à - à  2H+ and Oà  H2O +32 ATP

	The electron transport chain occurs in the mitochondria.
	Aerobic reaction
	Requires oxygen
	32 ATP released

High energy electrons are removed from the hydrogen leaving H+ ions and received by oxygen.
The oxygen and hydrogen ions combine forming water.
As the electrons are passed down the system their energy is released to allow the build up of ATP.

III). Fermentation

What happens if oxygen is not present?
No Oxygen  =   no electron transport chain

	Fermentation is an anaerobic process
	No oxygen needed
	Produce 2 ATP per pyruvate

Step 1:  Glycolysis produces 2 pyruvate acids and the coenzyme NAD picks up 2 hydrogens.
Step 2    NADH2 passes its hydrogens to pyruvate and forms lactic acid.

2ADP + Pyruvate + NADH2------à

2 ATP + Lactate + NAD

This is a representation of the workings of the Krebs Cycle

http://www.people.virginia.edu/~rjh9u/krebs.html