Week 7 Notes
Week 7 Notes Bio 208
Popular in Fundamentals of Cell Biology
Popular in Biological Sciences
This 8 page Class Notes was uploaded by Kylie McLaughlin on Sunday October 11, 2015. The Class Notes belongs to Bio 208 at Northern Illinois University taught by Dr. Ed Draper in Fall 2015. Since its upload, it has received 16 views. For similar materials see Fundamentals of Cell Biology in Biological Sciences at Northern Illinois University.
Reviews for Week 7 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: 10/11/15
Week 7 Notes Chapter 8 cont ATP adenosine triphosphate provides energy through hydrolysis reaction AG 73 kcamokm How the Hydrolysis of ATP Performs Work three types of cellular work mechanical transport and chemical are powered by the hydrolysis of ATP in the cell the energy from the exergonic reaction of ATP hydrolysis can be used to drive an endergonic reaction the coupled reactions are exergonic Glutamic acid ammonia gt glutamine AG 34 kcalmol Conversion reaction coupled with ATP hydrolysis Step 1 glutamic acid ATP gt phosphorylated intermediateess stable then glutamic acid ADP Step 2 phosphorylated intermediate ADP gt glutamine ADP Pi Free energy for coupled reaction Glutamic NH3 ATP gt glutamic acid NH3 ADP Pi AG glu 34 kcalmol AG ATP 73 kcalmol Net AG 39 kcalmol transport and mechanical work in the cell are also powered by ATP hydrolysis ATP hydrolysis leads to a change in protein shape and binding ability transport work ATP phosphorylates transport proteins mechanical work ATP binds noncovalently to motor proteins and is then hydrolyzed The Regeneration of ATP ATP gt hydrolysis gt ADP gt phosphorylation gt ATP ATP is a renewable resource that is regenerated by addition of a phosphate group to adenosine diphosphate ADP the ATP cycle is a revolving door through which energy passes during its transfer from cataboic to anabolic pathways ATP Cycle 1 Hydrolysis ATP H20 gt ADP Pi ATP is used for cellular work 2 Phosphorylation ADP Pi gt ATP H20 ATP is regenerated using energy from the cataboism of food the breakdown of sucrose is AG releases energy spontaneous how can any sucrose exist if it is energetically favorable for it to break down The Activation Energy Barrier every chemical reaction between molecules involves bond breaking and bond forming the initial energy needed to start a chemical reaction is called the free energy of activation or activation energy Ea this is bond breaking part activation energy is often supplied in the form of thermal energy that the reactant molecules absorb from their surroundings energy is released as new bonds form to make products Vocab Catalyst a chemical agent that speeds up a reaction without being consumed by the reaction Enzyme a catalytic protein does not change overall thermodynamics Substrate Speci city of Enzymes the reactant that an enzyme acts on is called the enzymes substrate the enzyme binds to its substrate forming an the reaction catalyzed by each enzyme is very speci c the is the region on the enzyme where the substrate binds of a substance brings chemical groups of the active site into positions that enhance their ability to catalyze the reaction Three Things Enzvme does 1 Enzyme binds to two substrate molecules and orients them precisely to encourage a reaction to occur between them 2 Binding of substrate to enzyme rearranges electrons in the substrate creating partial negative and positive charges that favor a reaction 3 Enzyme strains the bond substrate molecule forcing H toward a transition state to favor a reaction Enzyme Cycle 1 Substrate enters active site 2 Substrates are held in active site by weak interactions 3 Substrates are converted to products 4 Products are released 5 Active site is available for new substrates Environment can Effect Enzyme Activity each enzyme has an optional temperature in which it can function each enzyme has an optional pH in which it can function optimal conditions favor the most active shape for the enzyme molecule Cofactors nonprotein enzyme helpers may be inorganic such as metal in ionic form or organic an organic cofactor is called a coenzymes include vitamins Enzyme Inhibitors Competitive inhibitors bind to the active site of an enzyme competing with the substrate Noncompetitive inhibitors bind to the active site of an enzyme causing the enzyme to change shape and make the active site less affective Ex toxins poisons pesticides and antibiotics Regulation of Enzyme Activity Helps Control Metabolism chemica chaos would result if a cells metabolic pathways were not tightly regulated a cell does this by switching on or of the genes that encode speci c enzymes or by regulating the activity of enzymes can change location or where enzymes are and can limit reactions with substrate may either inhibit or stimulate an enzymes activity aosteric regulation occurs when a regulatory molecule binds to a protein at one site and effects the proteins function at another site poypeptides usually are allosterically regulated stabilize active or inactive form enzyme can catalyze more than 1 reaction cooperativity Feedback Inhibition start with a particular substrate many enzymes steps added until nal product end product allosteric can prevent rst step from happening inhibit any enzyme cannot inhibit itself enzyme go back step early in an enzyme requires input of energy once you get enough of the product this stops it from keep making products so it is not wasted Localization of Enzvmes within the Cell structures within the cell help bring order to metabolic pathways some enzymes act as structural components of membranes in eukaryotic cells some enzymes reside in speci c organelles for example enzymes for cellular respiration are located in mitochondria Chapter 9 Cellular Respiration and Fermentation energy has to ow into the system respiration in mitochondria is catabolic photosynthesis in chloroplasts is anabolic H20 02 and C02 are substrates and products C6H1206 glucose 602 6C02 6H20 energy end product is organic molecule and oxygen is released 1 Hydrolysis ATP H20 gt ADP Pi ATP is used for cellular work 2 Phosphorylation ADP Pi gt ATP H20 ATP is regenerated using energy from the catabolism of food Energy Released by ATP Hydrolysis Drive Endergonic Processes energy is needed for 1 Motility 2 Solute transport 3 Chemical reactions the target is quotenergizedquot by the temporary attachment of a phosphate group phosphorylation removing the phosphate dephosphorylation releases the energy needed for the reaction Redox Reactions 0xidation and Reduction Redox reduction and oxidation reactions Reduction gain of electrons Oxidation loss of electrons Oxidizing agent becomes reduced Cl Y Reducing agent becomes oxidized Na Xe Na Cl gt Na Cl Xe Y gt X Ye Na becomes oxidized loses electron and gains positive charge Cl becomes reduced gains electron and gains a negative charge Y becomes reduced Xe becomes oxidized Burning of Methane redox reaction reactants and products have the proper number of bonds and electrons Redox reduced carbon compounds and 02 change electron sharing from different compounds in the products C02 and H20 electrons are to oxygen than in the reactants this is due to the electronegativity of oxygen oxygen electrons and becomes reduced H20 is the most reduced form of oxygen C02 is the most oxidized form of carbon Biological reactions C6H1206 602 gt 6C02 6H20 energy C6H 1206 gtbecomes oxidized gt 6C02 602 gtbecomes reduced gt 6H20 CH4 202 gt C02 energy 2H20 CH4 gtbecomes oxidized gt C02 202 gt becomes reduced gt 2H20 nd the one that doesn39t have H in the reactants but has a lot in the products reduced nd the one that has a lot of H atoms in the reactants but none in the products oxidized NAD Nicotinamide Adenine Dinucleotide if we released all energy at once cell would have a hard time using it NAD is a coenzyme tries to release energy in steps this is important NAD so we can harvest energy shuttes electrons between chemicals NADH is what we use to store energy NAD is the oxidized form of NAD NADH is the reduced form of NAD NADH reducing power NAD0XidiZEd 2 electronshigh energy electrons from food 2H protons gt NADHreduced H FADH2 is another form of reducing power it is made during the oxidation of glucose does not have as great reducing power as NAD FAD oxidized 2 electrons high energy electrons from food 2H gt FADH2 reduced The Stages of Cellular Respiration harvesting of energy from glucose has three stages 1 Glycolysis breaks down glucose into two molecules of pyruvate 2 The citric acid cycle TCA completes the breakdown of glucose 3 Oxidative phosphorylation accounts for most of the ATP synthesis Phosphorya tion ATP synthesis ADP Pi gt ATP H20 in mitochondria ATP can be made by 1 Substrate level phosphorylation SLP 2 Oxidative phosphorylation Oxphos 90 is made this way SLP Substrate Level Ph05phorvlation singe enzyme simple process evolved rst small ATP yield ADP and a highenergy phosphate donor are substrates an exergonic reaction is coupled to an endergonic reaction transfers high phosphate donor to ADP ADP to ATP is endergonic Reaction 1 PEP gt pyruvate Pi AG 148 km Reaction 2 ADP Pi gt ATP AG 73 km Net reaction is exergonic AG 75 km get very few ATP molecules Overview of OxPhos Oxidative Ph05phorvlation process is complicated evolved later ATP yield Requires Reducing power Proton gradient Electron transport chain ETC Oxygen 02 Many other factors Mitochondria are sites of oxidative phosphorylation 02 is used to break down food and make ATP P PWF occurs in nearly I eukaryotic cells 1 Inner membrane from bacterial PM contains an ETC electron transport chain infoldings are cristae 2 Outer membrane from host PM 3 Matrix from cytoplasm of bacterial cell contains ribosomes DNA Krebs cyce enzymes Glycolysis harvests chemical energy by oxidizing glucose to pyruvate gycoysis quotsugar splittingquot breaks down glucose into two molecules of pyruvate occurs in virtually I prokaryotic and eukaryotic cells evolved early gycoysis occurs in the cytoplasm and has two major phases energy investment phase energy payoff phase gycoysis occurs whether or not 02 is present Net glucose 6C 2ADP 2NAD gt 2pyruvate 3C 2ATP 2NADH Oxidation of Pyruvate to Acetyl CoA in the presence of 02 pyruvate enter the mitochondrion in eukaryotic cells where the oxidation of glucose is completed before the critic acid cycle can begin pyruvate must be converted to acetyl coenzyme A acetyl CoA which links glycolysis to the citric acid cycle this step is carried out by a multienzyme complex that catalyzes three reactions Net 2 pyruvate 3C 2NAD 2CoA gt 2 acetylCoA2C 2NADH 2C021C The Citric Acid Cycle the citric acid cycle also called Krebs cycle or TCA completes the break down of pyruvate to C02 the citric acid cycle has eight steps each catalyzed by a speci c enzyme occurs in the mitochondrial matrix 2 turns of the cycle per 1 molecule of glucose Net Reaction per glucose Reactants gt Products 2 acetylCoA 4 C02 2 ADP 2 ATP 6 NAD 6 NADH 2 FAD 2 FADH2 1 2 turns of the cycle per glucose 2 Reaction 1 oxidation 4C acetyl 2C gt citrate 6C 3 4 oxidation reactions yield lots of reducing power 3 NADH 1 FADH2 per acetylCoA 6 NADH 1FADH2 per glucose 4 1 ATP is made by SLP involves a GTP intermediate
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'