Chapter 9.3 Martin
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 CO 2 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 H 2 O 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