The Process of Cellular Respiration

The Process of Cellular Respiration Converts Chemical Energy Found In the Organic Molecules of Food Into ATP, a Useful

Form of Energy Used to Fuel Metabolism

Organic Molecules in All Types of Nutrients Are Processed Through Cellular Respiration

ATP: Adenosine Triphosphate Is the Energy Currency for Metabolism

• The bonds between the phosphates have stored potential energy. When these bonds are hydrolyzes the energy is released.

• ATP ↔ ADP + P

ATP “Powers” Most Cellular Work

The Sun Is the Ultimate Energy Source for All Living Things

• Light energy is converted into chemical bond energy by producers.

• This chemical energy is trapped in the bonds of organic macromolecules.

• Cellular respiration transforms the organic macromolecule bond energy into ATP phosphate bond energy.

Cellular Respiration Process to Extract Energy from Organic Molecules, Such as

Glucose has Three Stages

The Chemical Reactions of Cellular Respiration Involve Rearrangenment of Electrons from One Organic

Molecule to Another in Redox Reactions

Stage 1: Glycolysis

• Glycolysis occurs in the cytoplasm of all cells and it is anerobic.

• One 6C glucose is hydrolyzed into 2 (3C) pyruvates

• Energy released is used for substrate level phosphorilation of 2 molecules of ATP.

• Hydrogen electrons reduce 2 NAD+ to 2 NADH + 2H+

– NADH + H+ will proceed to the electron transport chain in the mitochondria, where their energy will power the oxidative phosphorilation of 3 ATP molecules.

Pyruvate Enters the Mitochondria

• Pyruvate is transported into the mitochondria, there it will undergo a series of chemical reactions resulting in the production of Acetyl Co A, carbon dioxide, and NADH + H+

Stage 2: The Citric Acid Cycle • Acetyl CoA enters the cycle and it is oxidized into 2 CO2

• The following are

generated in the process:– 3 NADH + H+

– 1 ATP– 1 FAD

• The cycle turns 2X’s per glucose. (cycle turns once per pyruvate)

Stage 3: The Electron Transport Chain: 34 ATP Are Produced by Oxidative Phosphorilation per Glucose

• The electrons from NADH flow down a series of redox reactions to finally combine with Oxygen.

• The Hydrogens of the NADH are translocated across the membrane and fall back down their concentration gradient through ATP synthase, their energy is used to make 34 ATP

One Glucose Yields About 38 Molecules of ATP During Aerobic Respiration

Fermentation Is Anaerobic Respiration

• In the absence of oxygen or if a cell lacks mitochondria, fermentation will occur.

• the pyruvate, formed during glycolysis, will be converted into lactic acid or ethyl alcohol.

• In the process NADH will be recycled back to NAD+

• NAD+ is essential for the glycolysis reaction to occur

2 Types of Fermentation: Lactic Acid & Alcoholic

We Are What We EatThe food we eat is digested into organic molecules which are transported by the bloodstream to our cells where these substances can be oxidized during cellular respiration and their energy converted into ATP energy. Alternately, the organic molecules, products of digestion, can be used by the cell for the biosynthesis of proteins, carbohydrates, lipids, and nucleic acids. The energy for this biosynthesis comes from ATP.