Chapter 9.3Martin

Cellular respiration: the process by which mitochondria break down food molecule to form ATP◦ Happens in 3 stages

1. Glycolosis: breaks down glucose No oxygen required (anaerobic)

2. Citric Acid Cycle Requires oxygen (aerobic)

3. Electron Transport Chain Requires oxygen (aerobic)

A. Glycolosis Glycolosis: a series of chemical reactions

in the cytoplasm of a cell that breaks down glucose (a 6-carbon molecule) into two molecules of pyruvic acid (3-carbon molecules)

2 molecules of ATP are required to start this process

Only 4 are produced *(net 2 ATP gain)*

A. Glycolosis The pyruvic acid molecules move into the

mitochondria CO2 is produced from the pyruvic acid and

combines with co-enzyme A to form acetyl-CoA

B. The Citric Acid Cycle (Krebs Cycle) CAC: a series of chemical reactions similar

to the Calvin Cycle For every 1 turn of the cycle (for each

acetyl Co-A produced)◦ 1 ATP produced◦ 2 CO2 produced

CAC produces a net of 2ATP and 4 CO2 because of the 2 acetyl-CoA produced from glycolosis

C. Electron Transport Chain ETC is in the inner membrane of a

mitochondria The electron transport chain uses the high-

energy electrons from the Krebs Cycle to convert ADP to ATP

final electron acceptor is Oxygen, which reacts with 2 [H] ions and 4 electrons to form 2 molecules of H2O

Net of 32 ATP produced by the ETC

Anaerobic process that follows glycolosis Is the way we produce ATP until oxygen

becomes available 2 major types of fermentation

◦ 1. Lactic Acid Fermentation◦ 2. Alcoholic Fermentation

A. Lactic Acid Fermentation Pyruvic acid from glycolosis becomes lactic

acid Lactic acid builds up in muscle cells during

rapid exercise and can cause muscle fatigue Eventually, lactic acid is moved to liver

where it is reconverted back into pyruvic acid when oxygen is available

2 ATP produced

B. Alcoholic Fermentation Is used by YEAST cells and some bacteria to

produce CO2 and ethyl alcohol CO2 production is the cause of holes in

yeast made breads◦ Steak house rolls◦ Pizza dough

2 ATP produced