Intro to Metabolism

How do catabolic pathways yield energy?
Click the card to flip 👆
1 / 54
Terms in this set (54)
What is the cellular respiration equation? Is this endergonic or exergonic? Is this a negative or positive delta G? What is oxidized and reduced? Into what?C6H12O6 + 6O2 --> 6CO2 + 6H2O + Energy (ATP + heat); exergonic; negative; C6H12O6 is oxidized into 6CO2; 6O2 is reduced into 6H2OWhat 3 biomolecules can be consumed and processed as food?carbohydrates, proteins, fatsWhat does a negative delta G indicate?a reaction happened spontaneously AKA without an input of energyWhat must a cell do in order to keep working?regenerate its supply of ATP from ADP and PHow do the catabolic pathways that decompose glucose and other organic fuels yield energy?transfer of electrons during chemical reactions -- relocation of electrons releases energy stored in organic molecules, which is eventually used to synthesize ATPWhat are redox reactions?transfer of one or more electrons from one reactant to anotherWhat is oxidation? What is being oxidized in Xe-+ Y --> X + Ye- ?the loss of electrons from one substance, making the charge more positive; Xe-What is reduction? What is being reduced in Xe-+ Y --> X + Ye- ?the addition of electrons to another substance, REDUCING the charge; Y (O2 is usually reduced)What is the reducing agent? In Xe-+ Y --> X + Ye- ?the electron donor; Xe-What is the oxidizing agent? In Xe-+ Y --> X + Ye- ?the electron acceptor; YWhy don't all redox reactions involve the complete transfer of electrons from one substance to another? What is an example of this?some change the degree of electron sharing in covalent bonds; methane combustion (because in methane, the carbon and hydrogen bonds are all equally shared (electronegativity), and when methane reacts with oxygen, the carbon-oxygen bonds are shared less equally, and carbon partially loses its shared electrons AKA oxidized, and O2 partially gains electrons AKA reduced)What is the most potent of the oxidizing agents and why?oxygen -- its electronegativity is so highThe more electronegative an atom, the ________ energy is required to take an electron away from it.moreWhat type of energy change does an electron go through when it shifts from a less electronegative atom to a more electronegative atom?loses PEGenerally, what type of molecules are excellent fuels in redox reactions? Why?organic molecules with an abundance of hydrogen atoms -- their bonds are a source of 'hilltop' electrons, whose energy may be released as these electrons 'fall' down an energy gradient when transferred to oxygenIn the summary equation for respiration, where is hydrogen transferred from, and to what?glucose to oxygenWhat holds back the flood of electrons to a lower energy state?the barrier of activation energyWhat happens if energy is released from a fuel all at once?it cannot function efficiently for constructive workIn oxidation reactions, what does each electron travel with?a proton (hydrogen atom)What is NAD+?a coenzyme that functions as an electron carrier in which hydrogen atoms are passed toWhy is NAD+ well suited as an electron carrier?can cycle easily between oxidized NAD+ and reduced NADHIs NAD+ or NADH reduced?NADHIs NAD+ an oxidizing or reducing agent?oxidizing agentHow does NAD+ trap electrons from glucose in food?enzymes called dehydronases remove a pair of hydrogen atoms (2 electrons and 2 protons) from the substrate, oxidizing it, and the enzyme delivers the 2 electrons and 1 proton to NAD+ (the other proton is released as H+ - how NAD+ becomes NADH)What does each NADH molecule formed during respiration represent? When will this make ATP?stored energy; when electrons complete their 'fall' in a series of steps down an energy gradient from NADH to oxygenWhat is an electron transport chain?used by cellular respiration to break the fall of electrons into oxygen by several energy-releasing steps, consisting of a number of molecules (mainly proteins) built into the inner membrane of the mitochondriaHow do electrons that are removed from glucose get to the top of the electron transport chain? Is the energy level higher or lower here?NADH; higherWhat happens to the electrons at the bottom end of the electron transport chain?they are captured by O2 along with hydrogen ions, forming waterIs electron transfer from NADH to oxygen endergonic or exergonic?exergonicWhat type of reactions form a series in the electron transport chain?redoxAs you go down the electron transport chain, what happens to the carriers?they become less electronegative and small amounts of energy are lostWhen oxygen pulls electrons down the electron transport chain, is energy required?noIn cellular respiration, what is the standard downhill route for an electron? (4 parts)glucose --> NADH --> electron transport chain --> oxygenWhat are the 3 stages of cellular respiration? Which stages are technically considered cellular respiration?glycolysis, pyruvate oxidation/citric acid cycle, oxidative phosphorylation -- second 2In what does glycolysis occur in?the cytosolWhat is the function of glycolysis?breaks glucose into two pyruvateHow does the citric acid cycle begin?pyruvate enters the mitochon and is oxidized to Acetyl CoAWhat is the function of the citric acid cycle?breaks down glucose into CO2At the end of the electron transport chain, what are the electrons combined with?molecular oxygen and hydrogen ions -- forms waterWhat is oxidative phosphorylation?mode of ATP synthesis when the energy released at each step of the chain is stored in a form the mitochondria can use to make ATP from ADPWhat two processes constitute oxidative phosphorylation?electron transport and chemiosmomisOf all ATP generated in cellular respiration, how much of it does oxidative phosphorylation account for?roughly 90%What is substrate-level phosphorylation?mode of ATP synthesis where an enzyme transfers a phosphate group from a substrate molecule (instead of from an organic molecule)For each molecule of glucose degraded to CO2 and water by respiration, the cell makes up about ________ of ATP.32