Cellular Respiration Chapter 9

What is a calorie? The amount of energy need to raise the temperature of 1 g of H2O 1oC. * The Calorie used on food labels is actually a kilocalorie. * 1 g of C6H12O6 contains 3811 calories.

How do organisms release the energy found in C6H12O6? A 3 step process called cellular respiration. These are the steps: 1. Glycolysis – occurs in the cytoplasm 2. Krebs Cycle – occurs in the matrix of the mitochondria 3. Electron Transport chain – occurs on the inner membrane of the mitochondria

The overview of cellular respiration:

What is the difference between aerobic & anaerobic reactions? How do cellular respiration & photosynthesis compare? What is the difference between aerobic & anaerobic reactions? Aerobic = uses O2. The Krebs Cycle & ETC are aerobic Anaerobic = doesn’t use O2. Glycolysis is anaerobic.

Aerobic Respiration Step 1: Glycolysis A. Occurs in the cytoplasm B. Produces 2 ATP C. Produces 2 NADH - hi energy e- that will be used by the electron transport chain (ETC) D. Produces 2 pyruvic acid molecules - these will be used by the Krebs cycle

Aerobic Respiration Step 2: Krebs Cycle A. Occurs in the matrix of the mitochondria B. A.K.A the Citric Acid Cycle because it is temporarily made during this process C. Produces 1 ATP D. Produces 4 NADH - hi energy e- that will go to the ETC E. Produces 1 FADH2 F. Releases CO2 as a waste product * The main job of the Krebs Cycle is to make more hi energy e- for the ETC.

Aerobic Respiration Step 3: Electron Transport Chain A. Occurs on the inner membrane of the mitochondria. B. Electrons delivered by NADH & FADH2 travel down a chain of proteins. The electrons are then used to make H2O. O2 is used at this step. C. The movement of electrons pumps H+ across the inner membrane. D. The H+ then pass through an enzyme called ATP Synthase. 24 ATP are made here.

Aerobic Respiration For each molecule of C6H12O6, aerobic (cellular) respiration produces 36 ATP.

Anaerobic Respiration What is anaerobic respiration? The process of releasing the energy in C6H12O6 without the presence of O2. It is a two step process: Glycolysis – makes 2 ATP & 2 NADH Fermentation – turns NADH back into NAD+ * Anaerobic respiration only makes 2 ATP per glucose molecule.

Anaerobic Respiration Step 1: Glycolysis A. Produces 2 ATP B. Produces 2 NADH C. Produces 2 pyruvic acid molecules

Anaerobic Respiration Step 2: Fermentation A. Converts the pyruvic acid into a different molecule in order to regenerate NAD+. B. In Alcoholic Fermentation, pyruvic acid is turned into alcohol & CO2. C. In Lactic Acid Fermentation, pyruvic acid is turned into lactic acid.

Anaerobic Respiration