Biology Respiration

Learning Intentions 1. The main source of energy in cells is from glucose found in our food 2. What type of energy is in glucose? 3. How do cells release energy from glucose? 4. Describe the stages involved in respiration

1. Energy for cells Humans eat food for energy Food contains chemical energy Glucose (in food) is broken down by the process of respiration and its energy is stored in ATP Aerobic Respiration happens in the mitochondria of cells The chemical energy in ATP can be released by breaking it down.

2. Aerobic Respiration Respiration is the process by which chemical energy is released in cells during the breakdown of food e.g. glucose

3 Aerobic Respiration Aerobic Respiration involves the presence of oxygen and it occurs in 2 stages:- 1- Glycolysis 2- Breakdown of Pyruvic Acid

3a) Glycolysis Glycolysis produces 2 ATP

3b) Breakdown of Pyruvic Acid Pyruvic Acid + Oxygen 36ADP + 36Pi 36ATP Carbon Dioxide + Water This stage produces 36ATP Total ATP produced in Aerobic Respiration is 38ATP

4. Anaerobic Respiration In anaerobic respiration, only glycolysis occurs, so only 2 ATP are made In animals Glucose Lactic Acid In plants & fungi Glucose Ethanol + Carbon Dioxide

5. Comparing Aerobic & Anaerobic Respiration Humans Glucose + Oxygen￫Carbon Dioxide +Water Glucose ￫ Lactic Acid Plants & Fungi Glucose ￫ Ethanol + Carbon Dioxide ATP 38 ATP 2 ATP

6. Measuring the Rate of Respiration

7) Uses of Anaerobic Respiration Humans use the process of Anaerobic Respiration to make useful products e.g. Bread, Beer, Wine, The Anaerobic process that involves the chemical breakdown of a substance by microbes is also called Fermentation

8) Fermentation & Baking Industries yeast Glucose Ethanol + Carbon Dioxide Yeast is a single celled fungi that feeds on glucose. Carbon dioxide makes the dough rise The ethanol evaporates in the oven Practical -Yeast & height of dough

9) Fermentation & Brewing yeast Glucose Ethanol + Carbon Dioxide The ingredients for Beer can be added to large tanks called Fermenters. Yeast change the glucose into ethanol by the process of Fermentation. This is Anaerobic Respiration. Computers control the temperature and pH to provide the optimum conditions for the yeast Practical – Yeast, grape juice & a balloon!

10) Fermentation & Renewable Energy Bio-renewables are types of renewable energy produced by living things. Examples of Biorenewables are Biofuel, Biodiesel and Biogas Biofuel (e.g. Ethanol) Ethanol is made by fermenting the sugar in sugar cane, sugar beet, wheat, maize or wood pulp. Biodiesel (e.g. Alcohol and Oils) Biodiesel is produced by mixing alcohol with oils that have been extracted from plants such as rape seed, soybean or from waste vegetable oils Biogas (e.g. Methane) Biogas is produced from decomposing animal or plant waste. Practical – Producing Biodiesel

11 Fermentation & Dairy Industries YOGHURT MAKING bacteria Lactose Lactic Acid Sugar Bacteria feed on lactose sugar in milk The milk clots and becomes acidic making yoghurt Yoghurt Practical Wine, Yoghurt and cheese making video clip

11 Fermentation & Dairy Industries Bacterial Industries (Cheese) bacteria Lactose Lactic Acid Sugar Bacteria feed on lactose sugar in milk The milk clots and becomes acidic making yoghurt The enzyme Rennet is then added. Rennet clots the protein in milk to make curds, and the liquid part left is called the whey http://www.shetlandcheese.co.uk/2001.html

12. Fermentation Summary Brewing Baking Yoghurt Fungi (yeast) Bacteria Type of microbe Fungi (yeast) Bacteria Word Equation yeast Glucose Ethanol + Carbon Dioxide bacteria Lactose Lactic Acid Sugar