Prentice Hall - Science Explorer - Cells and Heredity
Chapter 2- Cell Processes and Energy
Section 2- Respiration
Questions - Comment - Key Words - ConnectionsRespiration Fermentation |
Main Ideas; Visuals + PredictionsWhat is Respiration?
Respiration: The process by which cells break down simple food molecules to release the energy they contain. * Obtaining the energy from glucose. Storing and Releasing Energy * During photosynthesis, plants capture the energy from sunlight and “save” it in the form of carbohydrates, including sugars and starches.* When cells need energy, they “withdraw” it by breaking down the carbohydrates in the process of respiration. Breathing and Respiration * Breathing means: Taking in oxygen to your lungs * Respiration or Cellular Respiration is: the breaking down of food to have the stored energy. The two stages of Respiration * The first stage takes place in the cytoplasm of the organism’s cells. There, molecules of glucose are broken down into smaller molecules. (No oxygen and only small amount of energy is released) * The second stage of respiration takes place in the mitochondria. There, the small molecules are broken down into even smaller molecules. (Requires oxygen and releases a lot of energy) The Respiration Equation
Comparing Photosynthesis and Respiration
* During photosynthesis, carbon dioxide and water are used to produce sugars and oxygen. * During respiration, the sugar glucose and oxygen are used to produce carbon dioxide and water. * Photosynthesis and respiration can be thought of as opposite processes. *This makes a cycle Fermentation
Fermentation: The process by which cells break down molecules to release energy without using oxygen. ex: single celled organisms in the ocean, in the mud of lakes, swamps. * The amount of energy released from each sugar molecule during fermentation, however, is much lower than the amount released during respiration. Alcoholic Fermentation * One type of fermentation occurs when yeast and some other single-celled organisms break down sugars. This process is sometimes called alcoholic fermentation because alcohol is one of the products. The other products are carbon dioxide and a small amount of energy. Lactic Acid Fermentation * when you run as fast as you can for as long as you can your muscle cells used up the oxygen faster than it could be replaced. Because your cells lacked oxygen, fermentation occurred. The fermentation supplied your cells with energy. * One product of this type of fermentation is an acid known as lactic acid. When lactic acid builds up, you feel a painful sensation in your muscles. |