RespirationRespiration

The energy making process that The energy making process that occurs continuously in all organismsoccurs continuously in all organisms

Stored chemical energy in food is Stored chemical energy in food is transferred to a form that organisms transferred to a form that organisms can usecan use

Exchanges of gases between Exchanges of gases between organisms and their environments organisms and their environments usually involvedusually involved

Cellular RespirationCellular RespirationC6H12O6 + O2 → ATP + H2O + CO2

•Enzyme controlled reaction that changes glucose into ATP

•ATP is hydrolyzed releasing energy forming ADP

•Takes place in the mitochondria and the reaction is reversible

•Cell Respiration may be aerobic or anaerobic

•Aerobic cellular respiration- requires the use of free oxygen atoms

•Anaerobic cellular respiration- oxygen is not used

In the absence of oxygen, In the absence of oxygen, fermentation reactions produce fermentation reactions produce

alcohol or lactic acid, but no alcohol or lactic acid, but no additional ATPadditional ATP

Cellular RespirationCellular Respiration

Three Main Stages of Three Main Stages of RespirationRespiration

GLYCOLYSISGLYCOLYSIS THE KREB CYCLETHE KREB CYCLE

ELECTRON TRANSPORTELECTRON TRANSPORT

GlycolysisGlycolysis

The process in which 1 molecule of glucose is The process in which 1 molecule of glucose is broken in half, producing 2 molecules of broken in half, producing 2 molecules of pyruvic acid.pyruvic acid.

Takes place in the cytoplasmTakes place in the cytoplasm Requires a “little” energy to get things goingRequires a “little” energy to get things going 2 ATP in → 4 ATP out, 2 ATP net gain2 ATP in → 4 ATP out, 2 ATP net gain

Energy yield is small from glycolysis. The process is Energy yield is small from glycolysis. The process is very fast, producing thousands of ATP in a few very fast, producing thousands of ATP in a few milliseconds. Done WITHOUT oxygenmilliseconds. Done WITHOUT oxygen

GlycolysisGlycolysis

The Kreb CycleThe Kreb Cycle

Pyruvic acid is broken down into COPyruvic acid is broken down into CO2 2

in a series of energy extracting in a series of energy extracting reactionsreactions

Pyruvic acid enters the mitochondria, Pyruvic acid enters the mitochondria, a carbon is removed forming COa carbon is removed forming CO22, , electrons are removed and with the electrons are removed and with the help of coenzyme A it is converted help of coenzyme A it is converted into citric acid (contains 6 Carbons)into citric acid (contains 6 Carbons)

The Krebs CycleThe Krebs Cycle

Energy ExtractionEnergy Extraction

• Citric acid is broken down into citric acid a Citric acid is broken down into citric acid a 5 carbon5 carbon

• Along the way, 2 COAlong the way, 2 CO22 molecules are molecules are released, as well as, electrons.released, as well as, electrons.

• ONEONE MOLECULE OF ATP IS MOLECULE OF ATP IS GENERATED!GENERATED!

Electron Transport Chain Electron Transport Chain

Uses high energy electrons from the Uses high energy electrons from the Kreb cycle to convert ADP to ATPKreb cycle to convert ADP to ATP