Review for Exam 4 Kreb s Cycle 04 15 2014 Post glycolysis pyruvate Krebs Cycle in the presence of O2 o Glycolysis takes place in the cytoplasm Produces 2 molecules of pyruvate mEach pyruvate is converted to one Acetyl CoA o Krebs Cycle takes place in the mitochondrial matrix Releases 584 kcal of energy still in pyruvate redox 100 kcal released during glycolysis Pyruvate Acetyl CoA 2 Carbon molecule o 2 Acetyl CoA enter Krebs Cycle one for each glucose o Each Acetyl CoA produces 3 FADH 1 FADH2 2 CO2 1 ATP ATP produced from substrate level phosphorylation FAD FADH2 is an electron carrier like NAD o So in TOTAL 1 molecule of pyruvate produces 4 NADH 1 FADH2 1 ATP 3 CO2 Electron Transport Chain Converts energy in electron carriers to ATP Inner mitochondrial membrane NADH and FADH2 are oxidized to NAD and FAD by proteins o Series of redox reactions o Release electrons Energy in e s powers pumping of H across membrane Produces concentration gradient Oxidative Phosphorylation H ions diffuse across inner membrane DOWN gradient Intermembrane Space Mitochondrial Matrix Facilitated by ATP synthase Energy released powers formation of ATP with the help of ATP synthase o O2 is final electron acceptor This reduction produces H2O Why is the formation of ATP at the end of the electron transport chain called Oxidative Phosphorylation Because of oxygen s high oxidative property it allows a large amount of free energy to be made available for the synthesis of ATP via the establishment of a gradient of H The voltage between the inner mitochondrial membrane and matrix is variable Which of the following conditions would lead to a decrease in voltage A decrease in oxygen would reduce the energy available to pump H Less H pumped reduces the gradient so less differential and voltage Summary of Cellular Respiration Total ATP produced 25 29 per molecule of glucose Amount of NADH FADH2 is constant across cells species organisms Number of protons pumped across membrane per oxidation required to diffuse for formation of each ATP Other molecules ie Proteins Amino Acids Glycerol Fatty Acids also use cellular respiration but enter pathways at different points ETC oxidizes electron carriers back to NAD FADH o Uses highly electronegative components to pull electrons from carriers spontaneously without added energy o Larger differences in electronegativity between steps release more energy o O2 is terminal acceptor highly electronegative Oxidative Phosphorylation Movement of electrons from carriers releases energy Energy released powers pump to actively transport H across gradient increases gradient H diffusion back into matrix is facilitated by ATP synthase Energy released by diffusion powers ATP formation Large H gradient more ATP produced Photosynthesis Light Dependent Reactions o Produce ATP NADPH These DO NOT provide energy for cellular functions Do not leave chloroplast ONLY provide energy to produce sugar Transported throughout cell and later broken down by cellular respiration o Energy from sunlight Electrons Series of 2 redox reactions ETCs harness energy Energy used to produce ATP reduce NADP NADPH Light Waves transfer energy in photons Pass through objects absorbed reflected Wavelength absorbed varies by pigments present Non absorbed wavelengths are reflected Short Wavelengths High Energy o Plants contain Chlorophyll and Carotenoid Pigments ALL photosynthetic organisms have CHLOROPHYLL A Plants also have chlorophyll b Chlorophylls absorb blue red and reflect green Accessory pigments expand range of usable light Carotenoids reflect orange red yellow Pigments in Thylakoid Membranes Light reaction in Grana stacks of thylakoids Photosystems Aggregation of pigments in thylakoid membrane each has 1 reaction center Only reaction center passes e to ETC Many photosynthetic organisms have 2 distinct photosystems and ETCs E from PS II provide e s for PS I PS I II absorb different wavelengths PS II created proton gradient in stroma to produce ATP ETC after PS II generates ATP ETC after PS I NADP NADPH Oxidation of H2O replenishes electrons Photolysis A plant grown under green light would be expected to Produce very little energy since almost all green light being reflected During photosynthesis light energy converts to chemical energy by excitation of electrons If the ETC between PS I PS II begins to work inefficiently decrease ATP production In photosynthesis the ETC associated with just PS I Is used to reduce NADP to NADPH Light Independent Reactions The Calvin Cycle o Produces Glucose sugar o Respiration Oxidation of glucose releases 684 kcal mol o Photosynthesis Reduction of CO2 requires 686 kcal mol Energy provided by light dependent reactions provides energy for calvin cycle to fix carbon from CO2 and produce sugars o 3 main phases 1 Carbon fixation CO2 fixed by bonding to organic sugar molecule 6 CO2 make 1 glucose Fixation enzyme Rubisco super abundant 2 Reduction of the fixed carbons to produce sugars Addition of electrons from H atoms From oxidation of NADPH NADP Reduction produces G3P 3 C enter 1 G3P leaves cycle 3 Regeneration of Ribulose Bisphosphate RuBp Remaining G3P converted back into RuBP Powered by energy released by bond reformation after hydrolysis of ATP Total 6CO2 12H2O C6H12O6 6O2 6H2O The biomass dry weight of a tree comes primarily from In this diagram compound X is a CO2 accepter If CO2 is cut off the first effect In this diagram compound X is a CO2 accepter If light is cut off the first effect If you applied a herbicide that affected the ability of NADPH to be oxidized which aspect of photosynthesis would be most immediately affected Photosynthesis and Mass o If a plant produces more than needed to catabolize for ATP can use to make cellulose of store as starch Mass Increases Grows o If a plant cannot conduct photosynthesis it cannot produce sugar needed to fuel it It will break down stored sugars Plant mass decreases Modern Genetics Mendel Father of Modern Genetics o Crossed pea plants Character Feature of an organism that has multiple variants among individuals Can be inherited or acquired o Ie Flower color seed color seed shape o Each character is controlled by one gene Mendelian Trait A particular variant of a characteristic o Ie Purple white round wrinkled o Different phenotypes appearances of a characteristic gene True Breeding If self pollinated all offspring have same trait variant for character is interest o P Generation Parental o F1 Second Generation 1st Filial o F2 Third