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76 Cards in this Set
- Front
- Back
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What are the 3 key pathways of respiration?
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1) glycolysis
2) citric acid cycle 3) oxidative phosphorylation |
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What does energy flow into an ecosystem as?
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light energy
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What does energy leave the ecosystem as?
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heat energy
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In cellular respiration, what is being formed?
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ATP
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What are the waste products of cellular respiration?
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CO2 + H20
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What are catabolic pathways?
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metabolic pathways that release sotred energy by breaking down complex molecules.
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What are metabolic pathways?
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A series of chemical reactions that either builds a complex molecule (anabolic pathway) or breaks down a complex molecule into simpler compounds (catabolic pathway)
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What is anabolic pathway?
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A metabolic pathway that consumes energy to synthesize a complex molecule from simpler compounds.
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What is metabolism?
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the totality of an organism's chemical reactions, consisting of catabolic and anabolic pathways, which manage the material and energy resources of the organism.
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Does electron transfer play a role in anabolic or catabolic pathways?
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yes. A major role in the pathways. p. 162
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How do organic compounds possess potential energy?
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the arrangement of their atoms.
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What is fermentation?
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a partial degradation of sugars that occurs without the use of oxygen.
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What is aerobic respiration?
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oxygen is consumed as a reactant along with the organic fuel.
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Which is more prevalent and efficient, aerobic respiration or fermentation?
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aerobic respiration.
Most eukaryotic cells and many prokaryotic cells carry out aerobic respiration. |
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What is anaerobic respiration?
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When prokaryotes use substances other than oxygen as reactants in a similar process to aerobic respiration that harvests chemical energy without using any oxygen.
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True or False: Cellular respiration includes aerobic respiration and not anaerobic respiration.
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False. It includes both aerobic respiration and anaerobic respiration.
BUT, it is more often used as a synonym for aerobic respiration. |
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organic compounds + oxygen -->
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carbon dioxide + water + energy
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What four things can be processed and consumed as fuel?
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sugar, carbohydrates, fats and proteins.
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True or False: Fat is the fuel that cells most often use.
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False. Glucose is the fuel that cells most often use.
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True or False: Catabolic pathways directly move flagella, pump solutes across membranes, polymerize monomers and perform other cellular work.
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False. Catabolism is linked to work by ATP.
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How do the catabolic pathways that decompose glucose and other organic fuels yield energy?
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The relocation of electrons releases energy stored in organic molecules, and this energy is used to synthesize ATP
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What are redox reactions (oxidation-reduction reactions)?
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During a chemical reaction, there is a transfer of one or more electrons (e-) from one reactant to another.
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What is oxidation?
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When one substance loses an electron.
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What is reduction?
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The addition of electrons to another substance.
(adding ELECTRONS is called REDUCTION) |
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If Na goes from Na to Na+, is it being oxidized or reduced?
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oxidized
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When chlorine is going from Cl to Cl- is it being oxidized or reduced?
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reduced
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What is a reducing agent?
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The substance which donates the electron
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What is the oxidizing agent?
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The substance that accepts the electron
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True or False: You can have oxidation without reduction.
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False. Because an electron transfer requires both a donor and an acceptor, oxidation and reduction always go together.
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True or False: Redox reactions require the complete transfer of electrons from one substance to another.
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False. Some change the degree of electrons sharing in covalent bonds. When something is more electronegative.
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What element is the most potent of all oxidizing agents and why?
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oxygen because it is so electronegative. p. 164 Figure 9.3
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True or False: No energy is needed to pull an electron away from an atom.
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False. Energy must be added to pull an electron away from an atom.... like energy is needed to push a ball uphill.
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True or False: The more electronegative the atom, the less energy is required to take an electron away from it.
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False. The stronger its upll on electrons so more energy is needed. p. 164
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Does an electron gain or lose potential energy when it shifts from a less electronegative atom toward a more electronegative one?
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loses potential energy.
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During a redox reaction, is energy released?
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yes. chemical energy is released that can be put to work. p. 164
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Is the combustion of gasoline a redox reaction?
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yes. so is methane when a gas stove is burning.
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In cellular respiration, how is energy released?
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during cellular respiration, glucose becomes oxidized to CO2, and oxygen becomes reduced to water. When oxygen is reduced to water, it releases energy that can be used as work.
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Do organic molecules with a lot of hydrogen make good fuels? IE water
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Yes, because their bonds are a source of "hilltop" electrons, whose energy may be released as these electrons "fall" down an energy gradient when they are transferred to oxygen.
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Does the oxidation of glucose put the electrons in a higher or lower energy state?
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lower. The rest of the energy becomes available for ATP synthesis.
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What happens to the energy that is released during oxidation?
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it becomes available for ATP synthesis.
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What is the barrier of activation energy for glucose?
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It either needs to be burned in air at a high temperature, or a glucose enzyme must be used before it can react with oxygen.
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What happens if energy is released from a fuel all at once?
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it cannot be used efficiently for work.
p. 164 |
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During the steps of oxidation, are hydrogen atoms tranferred directly to oxygen?
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no. They are usually passed through NAD+ ,an electron carrier.
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True or False: In oxidation reactions, each electron travels with a proton.
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True. p. 164 ("thus as a hydrogen atom")
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What is NAD+?
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a coenzyme that acts as an electron carrier.
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What does NAD+ stand for?
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nicotinamide adenine dinucleotide
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NAD+ is a derivative of what vitamin?
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niacin
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True or False: As an electron acceptor, NAD+ functions as an oxidizing agent during respiration.
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True. p 164
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How does NAD+ trap electrons from glucose and other organic molecules?
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Enzymes called dehydrogenases remove a pair of hydrogen atoms (2 electrons and 2 protons) from the substrate (glucose as an example), thereby oxidizing it. The enzyme delivers the 2 electrons along with 1 proton to its coenzyme NAD+. The other proton is released as a hydrogen ion H+ into the surrounding solution. p. 164 Figure 9.4
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True or False: NAD+ is the most versatile electron acceptor in cellular respiration and functions in several of the redox steps during the breakdown of glucose.
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True. p. 165
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Do electrons lose a lot or a little of their potential energy when they are transferred from glucose to NAD+?
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a very little.
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Can NADH be used to make ATP?
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Yes. Each NADH molecule formed during respiration represents sotred energy that can be tapped to make ATP when the electrons complete their "fall" down an energy gradient from NADH to oxygen.
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What is electron transport chain?
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A chain consisting of a number of molecules, mostly proteins, built into the inner membrane of mitochondria of eukaryotic cells and the plasma membrane of aerobically respiring prokaryotes that helps break the fall of electrons to oxygen into several energy-releasing steps.
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What shuttles electrons removed from molecules to the top of the electron transport chain?
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NADH p.165
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What is usually at the bototm of the electron transport chain?
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oxygen, which captures the falling H+ and forms water
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Is the electron transfer from NADH to oxygen an exergonic or endergonic reaction?
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exergonic
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What is usually the terminal electron acceptor in the series of redox reactions?
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oxygen. It has a great affinity for electrons.
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Are each "downhill" carrier more electronegative than its "uphill" neighbor, or less?
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More. Thus it is capable of oxydizing. p. 166
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When electron removed from glucose by NAD+ fall down an energy gradient in the electron transport chain, do they end up in a less stable, or more stable location?
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more stable location in the electronegative oxygen atom.
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What are the 3 stages of cellular respiration?
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1) Glycolysis
2) The citric acid cycle 3) Oxidative phosphorylation: Electron transport and chemiosmosis |
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True or False: Cellular respiration often leaves out glycolysis.
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True, it is sometimes defined as including only the citric acid cycle and oxidative phosphorylation but it is included in the book because most respiring cells deriving energy from glucose use this process to produce starting material for the citric acid cycle.
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Is Glycolysis a catabolic pathway or anaebolic?
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catabolic because they break down glucose and other organic fuels
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Is the citric acid cycle a catabolic pathway or anabolic?
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catabolic because they break down glucose and other organic fuels
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Where does Glycolysis occur?
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in the cytosol
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What does Glycolysis do?
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begins the degradation process by breaking down glucose into two molecules of a compound called pyruvate.
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Where does the citric acid cycle take place?
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in the mitochondrial matrix of eukaryotic cells or in the the cytosol of prokaryotes.
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What does the citric acid cycle do?
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Completes the breakdown of glucose by oxidizing a derivative of pyruvate to carbon dioxide.
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True or False: Carbon dioxide produced by respiration represents fragments of oxidized organic molecules.
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True. The citric acid cycle.
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What is oxidative phosphorylation?
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A mode of ATP synthesis that is powered by the redox reactions of the elctron transport chain.
p. 166 |
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In eukaryotic cells, where is the site of electron transport?
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in the inner membrane of the mitochondrion
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In eukaryotes, where is the site for chemiosmosis?
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in the inner membrane of the mitochondrion.
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What two processes make oxidative phosphorylation?
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electron transport and chemiosmosis
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In prokaryotes, where is the site for electron transport and chemiosmosis?
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in the plasma membrane
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True or False: Oxidative phosphorylation does not account for very much of the ATP generated by respiration.
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False. It accounts for 90%, a smaller amount if formed directly in a few reactions of glycolysis and the citric acid cycle by substrate-level phosphorylation.
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What is substrate-level phosphorylation?
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a mode of ATP synthesis that occurs when an enzyme transfers a phosphate group from a substrate molecule to ADP instead of adding an inorganic phosphate to ADP as in oxidation phosphorylation.
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Compare and contract aerobic and anaerobic respiration.
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Both processes include glycolysis, the citric acid cycle, and oxidative phosphorylation, but in aerobic respiration the final electron acceptor is oxygen, whereas in anaerobic respiration, the final electron acceptor is a different substance.
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