Outline I. Cellular Respiration A. Glycolysis B. The Kreb’s cycle or (Citric Acid Cycle) C. Electron Transport Chain

Cellular Respiration Overview Cellular Respiration is the process that releases energy by breaking down food molecules in the presence of oxygen. Transformation of chemical energy in food into chemical energy cells can use: ATP These reactions proceed the same way in plants and animals. 6O 2 + C 6 H 12 O 6  6CO 2 + 6H 2 O + Energy Oxygen + Glucose  Carbon Dioxide + Water + Energy

Cellular Respiration Overview Breakdown of glucose begins in the cytoplasm in the process of glycolysis At this point the biochemical pathway can go in one of 2 directions: – Anaerobic cellular respiration (aka fermentation) – Aerobic cellular respiration

C.R. Reactions Glycolysis – Series of reactions which break the 6-carbon glucose molecule down into two 3-carbon molecules called pyruvate – Process is an ancient one-all organisms from simple bacteria to humans perform it the same way – Yields 2 ATP molecules for every one glucose molecule broken down – Yields 2 NADH per glucose molecule (NAD is a “cousin” of NADP – works the same way) – Occurs with or without oxygen

Aerobic Cellular Respiration Oxygen required=aerobic Consists of two biochecmical pathways which occur in a specialized structure within the cell called the mitochondria – 1. Krebs Cycle – 2. Electron Transport Chain

Kreb’s Cycle Operates under aerobic conditions only. Converts the two-carbon compound to C0 2 Produces reduced coenzymes NADH and FADH 2 and ATP directly

Production of pyruvate, & citric acid cycle take place in matrix

Electron Transport Chain 1)Occurs mitochondria 2)A series of reactions where electrons are passed one membrane-bound protein/enzyme to another 3)34 ATP are formed by this process. 4)The final electron acceptor is oxygen The oxygen + 2 hydrogen = H 2 0

Energy Tally 36 ATP for aerobic vs. 2 ATP for anaerobic – Glycolysis 2 ATP – Kreb’s 2 ATP – Electron Transport34 ATP 38 ATP