AP Biology Cellular Respiration Overview Part 1

Process of Cellular Respiration

Compare to Cellular Respiration? BIG PICTURE FOR CELLULAR RESPIRATION: – 1. Break down a carbon-based molecule to create electron carriers. ** Glycolysis and Krebs Cycle.** – 2. Use the electron carriers to set up a concentration gradient of H+ ions, so that they can be used to make ATP. **ETC** – Use oxygen as a final acceptor of the electrons used to make ATP. Oxygen is INCREDIBLY IMPORTANT to the process of cellular respiration. **ETC**

Overview of Cellular Respiration Cellular Respiration is a Three Step Process: – Step 1: Glycolysis : This is the breaking of Glucose into 2 molecules of Pyruvate. ( All organisms can do this process as it occurs in the cytoplasm of a cell.) – Step 2: Kreb’s Cycle : This is all about making electron carriers due to the continued break down of Glucose. – Step 3: Electron Transport Chain : This is where the Free E of the electrons is used to help make ATP. This is referred to as Oxidative Phosphorylation (makes 90% of ATP) because it will need oxygen to be present. The whole process yields a maximum of 38 ATP/ 95% of time only 36 produced though.

Light energy Photosynthesis in chloroplasts Cellular respiration in mitochondria Organic molecules + O 2 CO 2 + H 2 O ATP powers most cellular work Heat energy Energy Coupling: The connection, using energy, between photosynthesis and cellular respiration. This process is, in its simplest form, a series of anabolic and catabolic reactions that work together to create organic molecules and break those molecules down to create energy.

Electron Transport chain creating a concentration gradient in a Thylakoid

“Building” the proton concentration gradient Protein complex of electron carriers H+H+ ATP Glycolysis Oxidative phosphorylation: electron transport and chemiosmosis Citric acid cycle H+H+ Q III I II FAD FADH 2 + H + NADH NAD + (carrying electrons from food) Inner mitochondrial membrane Inner mitochondrial membrane Mitochondrial matrix Intermembrane space H+H+ H+H+ Cyt c IV 2H / 2 O 2 H2OH2O ADP + H+H+ ATP synthase Electron transport chain Electron transport and pumping of protons (H + ), Which create an H + gradient across the membrane P i Chemiosmosis ATP synthesis powered by the flow of H + back across the membrane Oxidative phosphorylation

Series of Redox reactions (Electron Transport chain) The electron transport chain in cellular respiration is very similar to the process that takes place in photosynthesis. The proteins that work together to move electrons down the chain are different (except for cytochrome C) but the process is nearly the same.

Redox reaction

“Making” of electron carriers NAD⁺ +2 electrons + H⁺ ion = NADH FAD⁺ + 2 electrons + 2 H⁺ ions = FADH₂

Oxygen is at the end