4.4 Overview of Cellular Respiration

Cellular Respiration… Is a process that makes ATP by breaking down sugars (glucose). Cellular respiration is aerobic, or requires oxygen. Three Stages: Glycolysis Krebs Cycle Electron Transport Chain

Cellular respiration takes place in the mitochondria!!!

Step 1: GLYCOLYSIS MUST happen FIRST…REQUIRED for Cellular Respiration. Anaerobic process (does NOT require oxygen) Takes place in cytoplasm Enzymes split glucose into two three-carbon molecules Pyruvic Acid Produces two ATP molecules

Step 2: The Krebs Cycle Is the first main part of cellular respiration. Produces molecules that carry energy to the second part of cellular respiration.

Stage 2: KREBS CYCLE (Aerobic Pathway) takes place in the matrix of the mitochondria breaks down three-carbon molecules from glycolysis (Pyruvic Acid molecules) Regulated by enzymes Makes 2 molecules of ATP Releases carbon dioxide Transfers energy-carrying molecules to Electron Transport Chain NADH & FADH2

energy from glycolysis 6H O 2 6CO 6O mitochondrion matrix (area enclosed by inner membrane) inner membrane ATP energy energy from glycolysis 4 3 and

Step 3: The Electron Transport Chain Second main part of Cellular Respiration takes place in the inner membrane of the mitochondria Uses energy from Krebs Cycle to drive electron transport chain Oxygen enters process 32-34 molecules of ATP produced water released as a waste product Formed when enzyme combines hydrogen and oxygen

energy from glycolysis 6H O 2 6CO 6O mitochondrion matrix (area enclosed by inner membrane) inner membrane ATP energy energy from glycolysis 1 4 3 and

Products of Cellular Respiration-including Glycolysis 6 molecules Carbon dioxide from the Krebs cycle and Glycolysis 6 molecules of water from the electron transport chain A net gain of up to 38 ATP molecules for every glucose molecule 2 from glycolysis 2 from the Krebs cycle 32-34 from the electron transport chain

Glucose + Oxygen  Carbon dioxide + Water + Energy The equation for the overall process of Cellular Respiration is: C6H12O6 + 6O2  6CO2 + 6H2O + ATP Glucose + Oxygen  Carbon dioxide + Water + Energy

Relationship between Photosynthesis & Cellular Respiration: The reactants in photosynthesis are the same as the products of cellular respiration.

Cellular Respiration