Cellular Respiration

Chapter 9 Section 1

Cellular Respiration Overview Process that releases energy by breaking down food in the presence of oxygen. 6 O2 + C6H12O6  6 CO2 + 6 H2O + energy Occurs in all Eukaryotic cells (plants and animals) Uses the electron carrier molecule: NAD+  NADH and FAD+ FADH2

Glycolysis Glucose is broken down in half in the cytoplasm. Releases small amount of energy. (90 % is still unused). Does NOT require oxygen but does require 2 ATP to get it started. Releases small amounts of energy. 4 ATP are produced (but only 2 are gained because you used 2 to get the process started) along with 2 molecules of pyruvic acid and 2 NADH.

Review Questions Where does glycolysis occur? Does glycolysis require oxygen? What is the net gain of ATP after glycolysis? How many ATP are needed to get glycolysis started? What are the reactants of Cellular respiration? What are the products of cellular respiration?

NO OXYGEN!!!! Fermentation (anaerobic) – process that releases energy from food molecules by producing ATP in the absence of oxygen. NADH converted back into NAD+ allows glycolysis to continue which produces a steady supply of ATP

Two Main Types of Fermentation after glycolysis Alcoholic fermentation Lactic acid fermentation Pyruvic acid + NADH  alcohol + CO2 + NAD+ Yeast, a few microorganisms, used to produce beer, wine Baking bread…alcohol evaporates and Co2 bubbles create the holes. Pyruvic acid + NADH  lactic acid + NAD+ Occurs when body cannot supply enough oxygen to muscle cells…Causes the burning sensation Unicellular organisms, cheese, yogurt

Review Questions Fermentation releases energy from food molecules in the absence of … The first step in fermentation is always… What are the 2 main types of fermentation? What type of fermentation occur in your muscle cells?

Objectives Chapter 9 Section 1 Explain what cellular respiration is Describe what happens during the process of glycolysis Name the two main types of fermentation

Objectives Chapter 9 Section 2 Describe what happens during the Krebs cycle. Explain how high-energy electrons are used by the electron transport chain. Compare photosynthesis and cellular respiration.

Chapter 9 Section 2

OXYGEN!!!! Cellular Respiration (aerobic) Occurs in the Mitochondria after glycolysis Two parts after glycolysis : Krebs cycle (citric acid cycle) electron transport chain

Krebs cycle (Citric Acid cycle) The Krebs cycle takes 1 Pyruvic acid (from glycolysis) and breaks it down into 3 carbon dioxide molecules, which are released into the air, and a citric acid. High energy electrons are picked up by carrier molecules NAD+ and FAD+ and are carried off to electron transport chain. 2 ATP molecules are produced (1 per Pyruvic acid molecule).

Electron Transport Chain High energy electrons are carried by full electron carriers NADH and FADH2 to the electron transport chain to convert ADP to ATP by moving H+ ions across the membrane forming water. 32 ATP are produced

Order and tallies!!!! Glycolysis  Krebs Cycle  electron transport chain 36 ATP molecules produced during glycolysis and cellular respiration. (2 from glycolysis, 2 from Krebs, 32 from electron transport chain)