★When solute concentrations are equal on both sides of the diffusion barrier the molecules no longer move--False★★Active transport requires energy and employs a carrier molecule★★Passive transport movement down a concentration gradient and may employ a carrier molecule★★Would it be a good idea to give a severely dehydrated person an IV solution of sterile water? No, it will be hypotonic to the blood cells, and the red blood cells will lyse★★When solute concentrations are equal on both sides the molecules no longer move? False, there is no longer any net movement but there is still movement★★Isotonic marine invertebrates tend to neither gain nor lose water★Bind to an enzyme and help speed up reactionThe ability to reduce (i.e. donate) eletronsTo control when and where specific enzyme areInvolve transfer of electrons and hydrogensEmploy carrier moleculesCoenzymes/cofactors cycle between reduced and oxidized formsReduction= addition of electrons or hydrogen to a molecule (adds energy)Oxidation=the removal of electrons or hydrogens from a molecule (reduces energy)**Catabolic reactions are exergonic** produce ATP and reducing power**Anabolic reactions use reducing power and use ATP**catabolic: reactions that break down more complex moleculesAnabolic: biosynthesis, building larger structures/moleculesActive transport of hydrogen ions powered by the flow of electrons along the ETC (Electron Transport Chain)Moves proton down concentration gradient to produce ATP from ADPOxidative phosphorylationInvolves redox reactionsChemiosmosisEnergy stored in the form of an H ion gradient across a membrane is used to drive cellular work, such as ATP synthesis**Which has more energy, glucose or CO2? Glucose****Which has more energy, ATP or glucose? Glucose****Which has more energy, ATP or NADH? NADH****Which has more energy, NADH or FADH2? NADH**Glucose: -686 kcal/molFeedback inhibitionEnd product of anabolic pathway inhibits the enzyme that catalyzes an early step of pathwayPrevents needless diversion of key metabolic intermediates from uses that are more urgentIf cell is working hard and ATP drops, respiration speeds up and vice versaPhosphofructokinasePacemaker of respirationAllosteric enzyme with receptor sites for specific inhibitors and activatorsInhibited by ATP and stimulated by AMP, which cell derives from ADPAs ATP accumulates, inhibition of enzyme slows down glycolysisEnzyme becomes active again as cellular work converts ATP to ADP (and AMP) faster than ATP is being regeneratedCitrate (1st product of Krebs)Inhibits phosphofructokinaseHelps synchronize rates of glycolysis and KrebsPhosphofructokinase and citrateAllosteric enzyme with receptor sites for specific inhibitors and activatorsInhibit ATP and stimulated by AMP**Where does the reducing power come from? NADH-glycolysis, NADH-Krebs cycle, FADH2 Krebs cycle**Leaves contain mesophyll cells which contain chloroplastChloroplasts are found mainly in the cells of the mesophyll, the tissue of the interior of the leafThykaloid, thykaloid space stroma granumCarbohydrate production uses CO2, ATP and NADPHProduces sugar G3PATP and NADPH come from light reactionsBegins by incorporating CO2 from the air into organic molecules already present in the chloroplast—carbon fixationThen reduces fixed carbon to carbohydrate by adding of electrons (reducing power provided by NADPH acquired through light reactions)Calvin cycle makes sugar, but it can do so only with the help of the NADPH and ATP produced by the light reactantsSometime referred to as dark reactions because none of the steps require light directlyOccurs during daylight, for only then can light reactants provide the NADPH and ATP requiredChloroplasts uses light energy to make sugar by coordinating the two stages of photosynthesisLight and H2O (split)ATP, reducing power (NADPH), O2 as a by-product is producedDo not produce sugarWater is split, providing source of electrons and hydrogen ions from water to an acceptor called NADP+, where they are temp storedUse solar power to reduce NADP to NADPH by adding a pair of electrons along with H+Generate ATP using chemiosmosis to power the addition of a phosphate group to ADP (photophosphorylation)Light energy is initially converted to chemical energy in the form of two compounds: NADPH, a source of electrons as “reducing power” and ATPThykaloid membranes of the chloroplastsA photosystem is composed of a protein complex called a reaction-center complex surrounded by several light harvesting complexesPhotosystem I: light-capturing unit in a chloroplast’s thykaloid membraneHas two molecules of p700 chlorophyll a at its reaction centerPhotosystem II: has two molecules of p680 chlorophyll a at its reaction center1. Generated by the electron transport chain2. Generates ATP using ATP synthase (produces ATP)3. Similar to the ATP synthase of mitochondriaAn enzyme catalyzes the splitting of water into two electrons, two H and OPlants split H2O as a source of electrons from H atoms, releasing O2 as a byproductProduces ATPa. Chloroplasts and mitochondriab. Light reactionsc. Calvin-Benson cycleA plant that uses the Calvin cycle for in the initial steps that incorporate CO2 into organic material, forming a 3-carbon compound as the first stable intermediateC4 PlantsA plant in which the Calvin cycle is preceded by reactions that incorporate CO2 into a 4-carbon compound, the end product of which supplies CO2 for the Calvin cycleCAM PlantsCrassulacean acid metabolismA plant that uses CAM, an adaptation for photosynthesis in arid conditions. In this process, carbon dioxide entering open stromata during the night is converted to organic acids, which release CO2 for the Calvin cycle during the day when stomata are closedA metabolic pathway that consumes O2 and ATP, releases CO2 and decreases photosynthetic outputOccurs in the light (photo) and consumes O2 while producing CO2 (respiration)Unlike cellular respiration, does not generate ATP—it consumes itDecreases photosynthetic output by siphoning organic material from the Calvin cycle and releasing CO2 that would otherwise be fixedGenerally occurs on hot, dry, bright days when stromata close and the oxygen concentration in the leaf exceeds that of CO2O2 binds to Rubisco instead of CO2, resulting in no photosynthetic outputA microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plantWater
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