Bio 101 Study Guide For Exam 3

Bio 101 Study Guide For Exam 3 - I. Energy and Enzymes...

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I. Energy and Enzymes (Chapter 6) Explain how life is a combustion process. Compare combustion of a match with combustion of glucose in a cell. Heat, Light, and energy are released during combustion and are also released during the burning of a match. How is ATP involved with harvesting energy from fuel (food) sources? ATP is used to start cellular respiration. Cellular respiration produces more ATP. Explain how metabolism is efficient. Cells must extract energy in a controlled manner. The reaction occurs via many small steps. Enzymes catalyze each step of reaction. Energy captured is maximized and energy lost is minimized. Explain how metabolism is specific. Enzymes only bind to a specific type of molecule, substrate. Only fuel molecules burn. Enzymes only lower activation energy for molecules in reactions. Metabolic pathways have many enzymes each of which catalyzes only one reaction involving one substrate. What role do enzymes play in cellular metabolism? They continuously synthesize and breakdown molecules. They catalyze each step of reaction, speed up the chemical reaction. What is energy of activation for a chemical reaction? The activation energy of a reaction is the amount of energy needed to start the reaction. It represents the minimum energy necessary for a specific chemical reaction to occur. How is activation energy affected by enzymes? Enzymes lower activation energy for molecules in reactions. What are catabolic and anabolic reactions? Two types of metabolic reactions take place in the cell: 'building up,' anabolism, and 'breaking down,' catabolism. Complex molecules are synthesized from simpler substances in anabolism, ex: linking of amino acids to form proteins. Anabolic reactions use up energy. They are endergonic. Larger molecules are broken down into smaller ones, ex: degradation of starch to form monosaccharides. Catabolic reactions give out energy. They are exergonic How does ATP function in supplying energy for life processes? Assembling ATP stores energy and Breaking up ATP releases energy. ATP contains 3 phosphates and adenosine. The 3 rd phosphate can be broken off easily and when the bond is broken, energy is released. Cells are designed to capture and use energy released. Limited amount of adenosine in cells and at rest most is in form of ATP. When heavy exercise occurs much adenosine is ADP. ATP continuously replenished from spent ADP and phosphate. ADP and Pi using energy captured in metabolic pathways, such as breakdown of glucose. Energy stored in body as glycogen, fat, protein has to be converted to ATP before it can be used for work. 1
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What energy carrying molecules are involved in cellular respiration besides ATP? NAD, FAD, and NADP are the three other energy carrying molecules II. Cellular Respiration (Chapter 7) How do organisms use energy? Work in cells uses ATP and the ATP has to be replaced. Glucose, glycogen, etc. broken
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This note was uploaded on 04/09/2008 for the course BIO 101 taught by Professor Wetherbee during the Spring '08 term at Rhode Island.

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Bio 101 Study Guide For Exam 3 - I. Energy and Enzymes...

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