BSC 1010, Week 5 of Notes
BSC 1010, Week 5 of Notes BSC1010
Popular in Biology I
Popular in Biology
This 5 page Class Notes was uploaded by Betsabe Gonzalez on Sunday February 14, 2016. The Class Notes belongs to BSC1010 at Florida International University taught by Thomas Pitzer in Winter 2016. Since its upload, it has received 123 views. For similar materials see Biology I in Biology at Florida International University.
Reviews for BSC 1010, Week 5 of Notes
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 02/14/16
Chapter 7 ‘’Respiration” Cellular respiration: The process by which energy is harvested. The complete oxidation of glucose. Autotrophs: Organisms that harvest the energy from sunlight, through photosynthesis, converting radiant energy into chemical energy. Heterotrophs: organisms living on the organic compounds autotrophs produce, using them as food. Cells utilize enzyme facilitated redox reactions to take energy from food sources and convert it to ATP. Aerobic Respiration: When the final electron acceptor is oxygen (O2) Anaerobic Respiration: When the final electron acceptor is an inorganic molecule other than oxygen. (not O2) Fermentation: When the final acceptor is an organic molecule. Cellular Respiration is a series of reactions that are: -Oxidations: loss of electrons -dehydrogenations: lost electrons are accompanied by Hydrogen. Therefore what is actually lost is a hydrogen atom. During redox reactions, electrons carry energy from one molecule to another. NAD+ is an electron carrier -it accepts 2 electrons and 1 proton to become NADH -the reaction is reversible Forms of electrons carriers: (Reversibly oxidized and reduced) -Soluble carriers that move electrons from one molecule to another. -Membrane-bound carriers that form a redox chain. -Carriers that move within the membrane. Cells make ATP by two fundamentally different mechanisms: -In substrate-level phosphorylation ATP is formed by transferring a phosphate group directly to ADP from a substrate. -In oxidative phosphorylation ATP is synthesized by the enzyme ATP synthase using energy from a proton gradient. Oxidation of Glucose 1-Glycolysis 2-Pyruvate Oxidation 3-Krebs Cycle 4-Electron Transport Chain and Chemiosmosis 1- Glycolysis: Splitting the Glucose -Converts glucose to pyruvate -a 10 step biochemical pathway -Occurs in the cytoplasm -2 molecules of ATP are invested and 4 are produced -net production of 2 ATP molecules by substrate-level phosphorylation -2 molecules of pyruvate are formed -2 NADH produced by the reduction of NAD+ For glycolysis to continue, NADH must be recycled to NAD+ by either Aerobic Respiration or Fermentation. The fate of pyruvate depends on oxygen availability -If O2 is present, pyruvate is oxidized to acetyl – CoA which enters to the Krebs cycle -Without O2 pyruvate is reduced in order to oxidize NADH back to NAD+ The oxidation of Pyruvate to produce Acetyl – CoA -In the presence of oxygen, pyruvate is oxidized. -Occurs in the Mitochondria in eukaryotes. -Occurs at the plasma membrane in prokaryotes. -In mitochondria, a multienzyme complex called pyruvate dehydrogenase catalyzes the reaction. Products: -1 CO2 -1 NADH -1 Acetyl-CoA The Krebs cycle -Oxidizes the acetyl group from pyruvate. -Occurs in the matrix of the mitochondria -Biochemical Pathway of 9 steps 1 Step: acetyl group + oxaloacetate = citrate (2 carbons) (4 carbons) (6 carbons) The remaining steps of the Krebs cycle: -release 2 molecules of CO2 -reduce 3 NAD+ to 3 NADH -reduce 1 FAD to FADH2 -produce 1 ATP -regenerate oxaloacetate After glycolysis, pyruvate oxidation, and the Krebs cycle, glucose has been oxidized to: -6 CO2 -4 ATP -10 NADH -2 FADH2 The Electron Transport Chain (ETC) and Chemiosmosis ETC: series of membrane bound electron carriers -Embedded in the mitochondrial inner membrane -Electrons from NADH and FADH2 are transferred to complexes of the ETC -Each complex transfers the electrons to the next complex in the chain NADH dehydrogenase: Membrane embedded enzyme. The first of the proteins to receive the electrons. Ubiquinone: the carrier that passes the electrons to a protein – cytochrome complex called bc1 Bacterial Cytochrome C: the carrier that takes the electrons to the cytochrome oxidase complex. Chemiosmosis - The higher negative charge in the matrix attracts the protons (H+) back from the intermembrane space to the matrix. - The accumulation of protons in the intermembrane space drives protons into the matrix via diffusion. - Most protons move back to the matrix through ATP synthase. - ATP synthase is a membrane – bound enzyme that uses energy of the proton gradient to synthesize ATP from ADP + Pi Energy yield of Aerobic Respiration Theoretical energy yields: -38 ATP per glucose for bacteria -36 for eukaryotes Actual energy yield: -30 ATP per glucose for eukaryotes Regulation of Aerobic Respiration -Occurs by feedback inhibition: when cells possess plentiful amounts of ATP, the key reactions of glycolysis, the Krebs cycle, and fatty acid break down are inhibited, slowing ATP production. Control of glucose catabolism occurs at two key points in the catabolic pathway - Glycolysis: inhibited by ATP or citrate (enzyme phosphorylation) - Beginning of the Krebs cycle: inhibited by NADH (enzyme pyruvate dehydrogenase) Oxidation without O2 Respiration occurs without O2 via either: 1- Anaerobic respiration (final acceptor: inorganic molecule) 2- Fermentation (final acceptor: organic molecule) Reduces organic molecules in order to generate NAD+ Catabolism of Proteins and Fat Proteins: -amino acids undergo deamination to remove the amino group -remainder of the amino acid is converted to a molecule that enters glycolysis or the Krebs cycle. -Fats are broken down to fatty acids and glycerol -fatty acids are converted to acetyl groups by b-oxidation Evolution of Metabolism 1- Ability to store chemical energy in ATP 2- 3- Evolution of Glycolysis 4- Anaerobic Photosynthesis (using H2S) 5- Use of H2O in photosynthesis (not H2S) 6- Evolution of nitrogen fixation 7- Anaerobic respiration evolved
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'