Cellular Respiration: 9-1 Chemical Pathways Photo Credit: Duomo Photography, Inc.

Chemical Energy and Food Food serves as a source of raw materials for the cells in the body and as a source of energy. Animal Cells Animal Plant Mitochondrion Photo Credits: left: ©Bob Gurr/DRK Photo; middle bottom: ©John Durham/Science Photo Library/Photo Researchers, Inc. ; middle top: ©Ron Boardman/Stone; right: ©Keith Porter/Photo Researchers, Inc. Plant Cells

Chemical Energy and Food One gram of the sugar glucose (C6H12O6), when burned in the presence of oxygen, releases 3811 calories (3.8 Calories) of heat energy. A calorie is the amount of energy needed to raise the temperature of 1 gram of water 1 degree Celsius. The Calorie (capital “C”) used on food labels is a kilocalorie or 1000 calories.

Chemical Energy and Food Cells don't “burn” glucose. Instead, they gradually release the energy from glucose and other food compounds through a process called: Cellular Respiration: Glycolysis Krebs cycle Electron Transport Chain (ETC)

Overview of Cellular Respiration If oxygen is present (aerobic), glycolysis is followed by… the Krebs cycle and the electron transport chain.

Overview of Cellular Respiration Electrons carried in NADH Electrons carried in NADH and FADH2 Pyruvic acid Glucose Glycolysis Cytoplasm Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen. Glycolysis takes place in the cytoplasm. The Krebs cycle and electron transport take place inside the mitochondria. Mitochondrion

Cellular Respiration What is Cellular Respiration? Process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

Cellular Respiration The equation for cellular respiration is: 6O2 + C6H12O6 → 6CO2 + 6H2O + ATP oxygen + glucose → carbon dioxide + water + Energy

Cellular Respiration Each of the three stages of cellular respiration captures some of the chemical energy available in food molecules and uses it to produce ATP.

Where does each reaction take place? Glycolysis takes place in the cytoplasm. The Krebs cycle and electron transport take place in the mitochondria. Glycolysis Cellular respiration is the process that releases energy by breaking down food molecules in the presence of oxygen. Glycolysis takes place in the cytoplasm. The Krebs cycle and electron transport take place inside the mitochondria. Cytoplasm Mitochondria

The Totals: + 1 GLUCOSE: Glycolysis: 6 ATP Krebs, ETC: 30 ATP _______________ Total: 36 ATP

Review Questions Name the 3 steps of cellular respiration. What is the overall function of respiration? Where does glycolysis take place in the cell? Where do Krebs and ETC take place in the cell? Name the reactants of respiration. Name the products of respiration. Glycolysis, Krebs, ETC Provide energy in form of ATP (and electron carrying molecules) Cytoplasm Mitochondria Oxygen, glucose CO2 Water Energy