Ch. 9 Cellular Respiration Food and drink provide a source of energy for your cells that is used to make ATP calorie – the amount of energy needed to raise one gram of water one °C Kilocalorie (on labels) – 1000 calories Food provides the building blocks for your cellular products (proteins, hormones, etc.)

Overview of C. R. Cellular respiration can be aerobic (with O2) or anaerobic (without O2) Aerobic respiration has 3 steps: 1. Glycolysis 2. Krebs Cycle 3. Electron Transport Chain

Equation for C. R. 6O2 + C6H12O6  6CO2 + 6H2O + ATP (36-38) Oxygen and Glucose react forming carbon dioxide, water and ATP Other sugars, starch, fats and proteins can also be used as energy sources. Glucose is the simplest energy form ***Some energy released as heat

Glycolysis (splitting glucose) Occurs in the cytoplasm One glucose molecule split into two molecules of pyruvic acid Uses 2 ATP but makes 4 ATP. ATP net gain = _____ Makes 2 NADH Does NOT require oxygen

Let’s review…. Write the reaction equation for cellular respiration. What is the first step of C.R. called? Where does this step take place? What is broken down/What is formed? What is the net gain for ATP? Is oxygen needed?

The Krebs Cycle In the matrix of the mitochondria Pyruvic acid enters the cycle, where a series of enzyme-controlled reactions create NADH and FADH (energy carriers) Carbon dioxied (CO2) is a waste product

The Electron Transport Chain H+ ions made in Krebs cycle build up outside the inner mitochondrial membrane The H+ ions are forced through ATP synthase making 3 ATPs for each turn

E.T.C. Oxygen is used as the final electron acceptor H+ and oxygen combine to form water (a waste product) Without oxygen the process backs up and ATP can’t be made

Summary of Cellular Respiration Glucose is split into _________________ in the cytoplasm In the mitochondria, the _____________ makes CO2 and NADH and FADH ___________________ makes ATP on the inner membrane of the mitochondria Oxygen and hydrogen make water Total – 36 ATPs made by aerobic resp.

Anaerobic Respiration If your body uses energy very quickly, pyruvic acid can build up ATP is produced anaerobically by turning the pyruvic acid into lactic acid Lactic acid builds up in muscles and hurts! Intake of oxygen (heavy breathing) removes lactic acid from your muscles

Lactic Acid Fermentation Pyruvic acid + NADH  lactic acid + NAD+

Alcoholic Fermentation Fermentation is a valuable anaerobic process used to make ATP by yeasts and bacteria Fermentation produces CO2 and ethyl alcohol as by-products

Alcoholic Fermentation Pyruvic acid + NADH  alcohol + CO2 + NAD+

*Fermentation releases energy from food molecules by making ATP w/o oxygen Unicellular organisms produce L.A. Valuable in food/drink industry: yogurt, cheese, sauerkraut, pickles