Respiration Chapter 7 p. 132-147

ATP Reminders Main energy molecule Energy stored in bonds between phosphate molecules Energy comes from food we eat

The Importance of Electrons Energy to make ATP from ADP comes from movement of electrons Where do these electrons come from? We breathe so that oxygen can be the final electron acceptor from this process

Redox Reactions Oxidation- loss of electrons Ex: Reduction- gain of electrons Redox = Oxidation + Reduction The process by which electrons are transferred from one molecule to another

Electron Carriers Help with ATP formation Molecules that transfer electrons from one molecule to another Ex: NAD+ NAD+ is the oxidized form NADH is the reduced form

An Overview of the 3 Stages of Respiration 2 ATP

Where does each step occur? Glycolysis Krebs Cycle Electron Transport Chain

Cellular Respiration Produces 36 ATP molecules Aerobic- process that requires oxygen Releases carbon dioxide Uses electron carriers to transfer energy Enzymes enable electron transfers

Glycolysis Occurs in cytosol Requires energy input: 2 ATP Makes 4 ATP Begin with glucose (6C), end with 2 pyruvic acid molecules (3C) that go on to the Krebs cycle NET GAIN = TOTAL ATP =

Krebs Cycle Occurs in mitochondria Begins with pyruvic acid from glycolysis Cycle occurs 2 times for each molecule of glucose Makes 2 ATP Readies electron carriers for the electron transport chain TOTAL ATP =

Electron Transport Chain Occurs in mitochondria Makes remaining ATP using energy from the electron carriers TOTAL ATP =

What happens if no oxygen is present? Fermentation- anaerobic process (no oxygen) occurring when energy harvesting ends with glycolysis Way to recycle electron carriers since the energy is not used in the Krebs Cycle and Electron Transport Chain Causes cramps in muscles during exercise Yeast produce alcohol