Cellular Respiration Know these three types of energy As a biology student, there are only a few kinds of energy you need to know about. Light energy is the energy in light. Chemical energy is the energy stored in the chemical bonds of molecules. Kinetic energy is the energy of motion. Cells & Energy Cells get energy originally from the sun. In plant cells, chloroplasts trap light energy and change it into chemical energy. The chemical energy is stored in bonds between atoms of carbon, hydrogen, and oxygen. Cells & Energy (continued!) Chemical bonds hold atoms together to form molecules of sugar. Both plant and animal cells break down these molecules by breaking the chemical bond. When the bonds are broken, energy is released. Mitochondria in plant and animal cells use oxygen to release this energy. Cells & Energy (more!) Cells store energy from food in ATP molecules. When the cell needs energy, the ATP is broken down to release it. ATP! Adenosine Triphosphate Cellular Respiration The process by which living things release energy stored in organic molecules Takes Place in 2 major stages Glycolysis Oxidative Respiration or Fermentation I. Glycolysis - The splitting of glucose into 2 three Carbon molecules called Pyruvate Occurs in cytoplasm NAD is reduced to NADH CO is released 2 ATP produced Does NOT require OXYGEN 2 II. Anaerobic vs Aerobic A. Anaerobic (w/o O ) 2 Fermentation Process by which pyruvate is converted into either alcohol and CO or lactic acid Occurs in cytoplasm H from NADH is attached to pyruvate Only 2 ATP are produced 2 B. Aerobic (with O ) Oxidative Respiration – process by which pyruvate is broken down to form MOST of the energy which is supplied to plants and animals Occurs in mitochondria Occurs in 2 major phases 2 Krebs Cycle 2 ATP are produced Occurs in Matrix of Mitochondria Electron Transport Chain 32 ATP are produced Occurs in Inner Membrane of Mitochondria Each Cell uses between 1-2 billion ATP/min. How many ATP’s are used each minute by all 100 trillion cells in the body? 1 glucose = 686 Cal 1 ATP = 7 Cal How efficient is aerobic respiration? How does the efficiency of your cells compare to the efficiency of an automobile that are only 25% efficient in converting chemical energy into mechanical energy? Oxygen debt Oxygen is necessary to support the conversion of lactic acid to glycogen No Oxygen lactic acid build up Muscle Fatigue Inability of muscle to contract Results from a deficit of ATP and/or accumulation of lactic acid lowers pH What do you think of when you hear Fermentation? What affects the rate of cellular respiration in yeast? Through a process called cellular respiration, the cells of most organisms use oxygen to release the energy that is stored in food molecules. Fungi use a different process, called fermentation, that does not use oxygen to release energy. During both cellular respiration and fermentation, energy is released when the chemical bonds that hold the food molecules together are broken. All organisms then use elements, such as carbon, to build their own biological molecules. The molecules left after these processes are waste products. 1. What is the function of Cellular respiration? What organisms do this process? 2. What are the two steps of Cellular Respiration? 3. What are the end products of Glycolysis? 4. Where in the cell does Glycolysis occur? (cytoplasm or mitochondria) 5. How many energy molecules are produced from Glycolysis? 6. What are the two steps to oxidative respiration? 7. Where do both of these energy-producing steps occur within the cell? (Cytoplasm or mitochondria) One of the waste products is carbon dioxide, a molecule that contains carbon. As organisms conduct cellular respiration or fermentation, they release waste carbon dioxide as a gas into the atmosphere. Photosynthetic organisms, such as plants, absorb this carb dioxide and use it in photosynthesis. The carbon gets incorporated into parts of the plant (for example, as part of the starch in a potato) and may end being consumed by yet another animal. The constant cycling of carbon through organisms to the atmosphere and back again is called carbon cycle. Fermentation Question: What affects the rate of cellular respiration in yeast? Hypothesis: Materials: Procedure: (step by step recipe) Record: (data table, charts, etc) Analyze and conclude. Fermentation Analysis Questions Were you able to conclusively prove or disprove your hypothesis? What were your results? What sources of error were there in your experimental method? How might you reduce error if you did your experiment again? What affects the rate of cell respiration in yeast? 1. Does room temperature affect how much gas is created by the yeast? 2. Does the size of the container affect how much gas is created? 3. What water/room temperature helps the yeast create the most gas? 4. What "yeast food" helps the yeast create the most gas?
