Key Words anaerobic process: does not require O2 to occur aerobic process: requires O2 to occur glycolysis: biochemical pathway that breaks down glucose into pyruvic acid pyruvic acid: 3-carbon molecule made from glucose during glycolysis NADH: an energy-carrying molecule fermentation: another pathway that converts glucose into ATP

What is Cellular Respiration? how cells receive energy from nutrients breaks down organic molecules (ex: sugars) into ATP occurs in mitochondria (therefore, this occurs in both plants AND animals)

Equation for Cellular Respiration C6H12O0 + 6 O2 6 CO2 + 6 H20 (glucose) (oxygen) (carbon dioxide) (water) ------> REACTANTS (starting materials) PRODUCTS (end result)

Stages of Cellular Respiration Stage 1 – GLYCOLYSIS uses glucose made during photosynthesis breaks down glucose into 2 molecules of pyruvic acid in the process, a small amount of ATP and NADH is made What comes next depends on one factor… the presence of OXYGEN.

Stage 2 NO, there is not O2 present: YES, there is O2 present: Stage 2 = FERMENTATION creates lactic acid or ethyl alcohol these can be converted to ATP inefficient process (wastes energy) Stage 2 = AEROBIC RESPIRATION Has two stages: Krebs Cycle Electron Transport Chain (ETC)

Krebs Cycle Picks up where glycolysis left off. Takes 2 molecules of pyruvic acid (made in glycolysis), converts them into various molecules over several cycles involves enzymes such as Co-enzyme A Pyruvic acid is converted into Acetyl CoA via enzymes. When this occurs, CO2 is produced. End result: 2 molecules of ATP made in each cycle One glucose molecule will fuel two Krebs Cycle (therefore, 1 glucose -> 4 ATP)

Electron Transport Chain similar to photosynthesis occurs on the inner membrane of mitochondria transfers electrons throughout several molecules, building up energy when enough energy is built up (from NADH and FADH2), ATP is created NADH and FADH2 created during the Krebs Cycle chemiosmosis = production of ATP via chemicals