Life 102, Week 7 Notes
Life 102, Week 7 Notes Life 102
Popular in Attributes of Living Systems
verified elite notetaker
Popular in Life Science
This 4 page Class Notes was uploaded by Kyra Ferguson on Tuesday March 8, 2016. The Class Notes belongs to Life 102 at Colorado State University taught by Erik Arthun in Winter 2016. Since its upload, it has received 17 views. For similar materials see Attributes of Living Systems in Life Science at Colorado State University.
Reviews for Life 102, Week 7 Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
Date Created: 03/08/16
Carbohydrate Metabolism Complex carbohdyrates are hydrolyzed to monosaccharides which then enter into glycolysis Fat metabolism Fats are broken down into glycerol and fatty acids Glycerol is converted to glycerald hyde 3phosphate which enters glycolysis Fatty acids are broken down by betaoxidation to 2carbon molecules to enter citric acid cycle Protein metabolism Proteins are broken down into amino acids Amino groups are removed, and nitrogenous waste is excreted as ammonia (NH 3 Enter respiration of glycolysis or citric acid cycle Proteins have lower energy content than glucose Anabolic Pathways (Biosynthesis) The body uses small molecules to build other substances (fats, amino acids) These small molecules may come directly from food, from glycolysis, or from citric acid cycle Intermediates from glycolysis and citric acid cycle are diverted to anabolic processes Feedback Regulation Feedback Inhibition is the most common mechanism for control If ATP concentration begins to drop, respiration speeds up; when there is plenty of ATP, respiration slows down Control of catabolism is based mainly on regulating the activity of enzymes at strategic points on The Catabolic Pathway We can use ADP or ANP if there is not ATP, but it would requiring being in a bad enough situation that you lack ATP Cells can produce ATP in alternative ways Aerobic respiration needs O 2or electron transport chain If there is no 2 , glycolysis couples with fermentation or anaerobic respiration to produce ATP This produces less ATP, but is better than none. Anaerobic Respiration uses an electron transport chain with a final electron acceptor other than O2, for example: sulfate Fermentation Fermentation is an extension of glycolysis Uses substratelevel phosphorylation instead of an electron train It allows continuous phosphorylation and recycles NADH → NAD + Types of Fermentation Consists of glycolysis plus reactions that regenerate NAD , which can be reused by glycolysis Two common types are alcoholic fermentation and lactic acid fermentation In alcohol, pyruvate is converted to ethanol with releasing CO 2 Lactic acid, pyruvate is reduced by NADH, forming lactate as an end product, and does not release CO 2 Pyruvate is an important intersection in catabolism Energy Movement Through Ecosystems Energy flows into an ecosystem as sunlight and leaves as heat Chapter 10: Photosynthesis Light energy → chemical energy Photosynthesis means "light" and "build" Autotrophs "selffeeders" producers of all organic compounds in bioshpere Photoautotrophs capture energy from sunlight Heterotrophs "other feeders" consumers of organic compounds Photosynthesis converts light energy to the chemical energy of food Leaves: major location of photsynthesis, green color is from chlorophyll, the green pigment within cholorplasts CO 2enters and O 2xits the leaf through microscopic pores called stomata Chloroplast site of photosynthesis in plants membranes of thylakoid Contain stroma, a dense interior liquid Tracking Atoms through Photosynthesis Light + 6CO 2 12H O 2 C H O 6+12O 6+ 6H O2 2 Seems like the reverse of cellular respiration, but it isn't exactly. Chloroplasts split water, incorporating the electrons of hydrogen into sugar molecules and releasing oxygen as a biproduct Also a redox reaction How does photosynthesis work Light reactions light energy is captured in the thylakoid membrane Calvin Cycle CO2 is "fixed" and reduced to sugars in the stroma Photosynthesis consists of the light reactions (the photo part) and Calvin cycle (the synthesis part) The light reactions (in the thylakoids) o split H2O o release O2 o Reduce NADP to NADHPH o Generate ATP from ADP by photophosphorylation The Calvin cycle (in the stroma) forms sugar fromCO , us2ng ATP and NADHOH The Calvin cycle beings with carbon fixation, incorporating CO into2organic molecules Interactions between Leaves and Light Photons of light energy interact with chlorophyll molecules and other pigments in chloroplasts Light is Reflected Transmitted Absorbed Light absorption works because when a photon hits any molecule, it can push an electron into a higher energy level The excited electron falls back, and releases heat/radiation Rather than allowing the electron to fall back, it is captured by another molecule. Photosystem (PS) cluster of pigment molecules working together 2 types of photosystems: PS I and PS II both work together in photosynthesis Each PS has: Reaction center: central Chl molecule that receives all captured light energy Primary electron acceptor: molecule that accepts excited e from reaction center Consist of a reactioncenter complex surrounded by lightharvesting complexes The lightharvesting complexes (pigment molecules bound to proteins) transfer the energy of photons to the reaction center A primary electron acceptor in the reaction center accepts the excited electrons and is reduced Solar powered transfer of an electron from a chlorophyll a molecule to the primary electron acceptor is the first step of the light reactions Linear Electron Flow During the light reactions, there are two possible routes for electron flow: cyclic and linera Linear electron flow the primary pathway, involves both photosystems and produces ATP and NADPH using light energy A photon hits a pigment and its energy is passed among pigment molecules until it excites P680 An excited electron is transferred to the primary electron acceptor (P680 is now called P680 )