BIO 1102 how cells work
BIO 1102 how cells work BIO 1102
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This 2 page Class Notes was uploaded by Ashley Beals on Sunday September 11, 2016. The Class Notes belongs to BIO 1102 at University of Connecticut taught by A. Fry in Fall 2016. Since its upload, it has received 13 views. For similar materials see Foundations of Biology in Biology at University of Connecticut.
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Date Created: 09/11/16
Energy: The capacity to do work 1st Law of Thermodynamics: Energy can be changed from one form to another but cannot be created or destroyed. Each time energy changes from, some is lost, usually as heat. What is life’s main energy source? Sunlight What is life’s main energy carrying molecule? ATP adenosine triphosphate How does ATP transfer energy? It gives up its third phosphate group to become ADP Transfer of a phosphate group is called phosphorylation or dephosphorylation. ADP+P=ATP What are redox reactions? Oxidation reduction reactions. Electrons are transferred from one molecule to another. A molecule is oxidized if it gives up electrons a educed if it gains electrons. Electron transport chains: Molecules that accept and give up electrons in sequence. Electrons can give up energy at each step in the chain. Metabolic pathways: An enzyme controlled sequence of chemical reactions. a. Anabolic pathways: require inputs of energy. Construct high energy molecules from smaller molecules. The most important anabolic pathway is photosynthesis. b. Catabolic pathways: release energy. Break down molecules into smaller, low energy products. Most important catabolic pathway is cellular respiration What are enzymes made from? Proteins Substrate: molecules that bind to enzymes Active site: location on enzyme where substrate binds. Activation energy: the energy needed to start a chemical reaction. How do enzymes work?They lower activation energy needed to start a chemical reaction. Enzymes are important because a. Make chemical reactions faster b. They can be reused c. Lower activation energy Control over enzymes a. Cofactors: help enzyme function properly b. Environmental factors: Temp, pH, and salt have to be at a specific range for enzymes to work properly c. Allosteric activation or inhibiti other molecules that bind to an enzyme change the shape of the active site to block or allow reaction. d. Feedback inhibition: When a reaction product becomes too common Solvent: Something that dissolves something else. Solute: the stuff dissolved by a solvent Solution: A solvent plus solute(s) Diffusion: solute moves from area of high concentration to low concentration Osmosis: movement of water from area of high to low concentration Study tip: In diffusion the solute wants to move, in osmosis the solvent (water) wants to move What drives the movement of molecules in diffusion and osmosis? a. Heat energy colliding molecules. Steeper concentration gradient faster diffusion. b. Smaller solutes diffuse faster c. Higher temperature= faster diffusion Reverse osmosis: Purify water by forcing it through a semipermeable membrane to filter out contaminants. SA/V ratio: the surface area to volume ratio gets smaller as cell gets larger If a cell gets too big its surface are cannot keep up with the increasing v olume inside the cell and the cell won’t be able to move resources across the cell membrane fast enough. What can cross the cell membrane? Hydrophobic molecules: O CO . small 2npol2 molecules. What can not cross the cell membrane? Hydrophilic molecules: glucose, ions and large polar molecules. Passive transport: does not require energy. Movement concentration gradient high to low. Active transport: Does require energy. Movement against concentration gradient. Low to high. Exocytosis: moving something outside the cell Endocytosis: moving something from outside the to inside the cell Phagocytosis: cell eating.