Nutrients + oxygen  water + ATP + CO2 Cellular Respiration Cellular Respiration: Process by which mitochondria break down food molecules to produce ATP in plants and animals Nutrients + oxygen  water + ATP + CO2 Changes the chemical energy in glucose into the chemical energy in ATP

Cellular Respiration There are three stages of Cellular Respiration Glycolysis Anaerobic – does not require oxygen Citric Acid Cycle Aerobic – does require oxygen Electron Transport Chain

Glucose breaks down into 2 pyruvate and 4 ATPs (Net gain of 2 ATP) Glycolysis Glycolysis: Breaks down glucose into two molecules of pyruvic acid This reaction uses enzymes and takes place in the cytoplasm of the cell ATP Glucose Enzymes + 2 ATP Pyruvate ATP ATP Glucose breaks down into 2 pyruvate and 4 ATPs (Net gain of 2 ATP)

Glucose breaks down into 2 pyruvate and 4 ATPs (Net gain of 2 ATP) Glycolysis Glycolysis Animation Produces 2 pyruvic acid molecules (used in the next step of Cellular Respiration) 2 ATP molecules (energy the cell can use) ATP Glucose Enzymes + 2 ATP Pyruvate ATP ATP Glucose breaks down into 2 pyruvate and 4 ATPs (Net gain of 2 ATP)

Into the Mitochondria… Before the next step of Cellular Respiration can occur, the pyruvic acid molecules must go into the mitochondria. The two aerobic reactions are the Citric Acid Cycle (or Krebs Cycle) and the electron transport chain (or ETC). Pyruvic acid  CO2 + water + ATP

THE KREB’S CYCLE ATP NADH + FADH e - Citric Acid Cycle (Kreb Cycle) Pyruvate Pyruvate CO2

Electron Transport Chain ETC Animation Electron Transport Chain uses the electron carriers (NADH and FADH2) to pass electrons down the protein chain and slowly release energy that is used to form ATP and water molecules

Electron Transport Chain Cellular Respiration 2 ATP Glycolysis Glucose Pyruvic Acid CO2 Citric Acid Cycle Pyruvic Acid ATPs NADH and FADH Water NADH and FADH Electron Transport Chain Oxygen ATPs

Cellular Respiration Equation Cellular Respiration Video C6H12O6 + 6O2 6CO2 + 6H2O + energy Carbon Dioxide – waste product of the Citric Acid Cycle Water – released from Electron Transport Chain Glucose made in photosynthesis by plants or consumed by animals Used in Glycolysis ATP released from Glycolysis, Citric Acid Cycle, and Electron Transport Chain Oxygen from the atmosphere Used in Electron Transport Chain Between 34-36 ATP can be made with this process. This ATP can be used by the cells for cellular metabolism.

Fermentation When oxygen is not available (anaerobic respiration) fermentation can follow glycolysis in order to continue to produce energy. This is not as efficient as aerobic respiration and produces far fewer ATPs

Fermentation Two types of fermentation: Lactic acid Fermentation Alcoholic Fermentation

Lactic acid Fermentation Lactic acid fermentation occurs in muscle cells during strenuous exercise when a lot of energy is required and oxygen is scarce (oxygen debt). Glucose  pyruvic acid  lactic acid + ATP

Lactic acid Fermentation The lactic acid is transferred from the muscle cells to the liver where it will be converted back to pyruvic acid. The build up of lactic acid in the muscles is what causes them to be fatigued and sore.

Alcoholic Fermentation Yeast and some bacteria cells are capable of alcoholic fermentation during which glucose is broken down to release CO2 and ethyl alcohol Glucose  pyruvic acid  alcohol + CO2 + ATP

Alcoholic Fermentation The bubbles formed by the CO2 make bread rise The alcohol released turns grape juice into wine

Photosynthesis vs. Cellular Respiration Stores Energy as glucose Releases Energy in glucose Occurs in Living Cells Uses an Electron Transport Chain Occurs in Plant Cells Occurs in Animal Cells Releases Oxygen Releases Carbon Dioxide Creates Energy            Neither!