MCB 181 1nd EditionExam # 3 Study Guide Lectures: 14 – 21Outline of Exam #3 Study Guide:Review Session Questions and Answers (Extended)Review Session Questions and Answers (Extended)Cellular RespirationCellular respirationIt occurs in the mitochondria, which has two membranes where protons are accumulated.Know this image and how it worksWhat is the goal of cellular respiration?The ultimate goal is to produce energy in the form of ATP. It accomplishes this by breaking down glucose (glycolysis) for a net of 2 ATP. The two pyruvate and 2 NADH produced in glycolysis are carried to the mitochondria and after pyruvate processing, the Acetyl CoA enters the Krebs cycle and generates more ATP, NADH, and FADH2 which ultimately end in the ETC with 38 ATP produced.Glycolysis In glycolysis, 1 glucose molecule, 2 NAD+, and 2 ATP enter. It produces 4 ATP (net 2 ATP), two pyruvate molecules, and 2 NADH. You don’t need to know specifically how the process works just what goes in and out. This occurs in the cytosol of the cell.Pyruvate processingIn the inner membrane of the mitochondria, the pyruvate from glycolysis becomes oxidized (loses a carbon) and changes into Acetyl CoA. NAD+ is also reduced to form NADHin this step. The Acetyl CoA then moves on to the Krebs cycle, which takes place in the matrix. From this step, we produce 2 Acetyl CoA molecules, 2 NADH and CO2.Krebs CycleAcetyl CoA enters the Krebs cycle along with 2 FAD and 2 NAD+. This cyclic process changes its 3D structure. In the Krebs cycle, for the two Acetyl CoA that enter, we produce 6 NADH, 2 ATP, and 2 FADH2. Again, no need to memorize specific locations or processes, just what goes in and what comes out.Electron Transport Chain (Oxidative Phosphorylation)10 NADH and 2 FADH2 enter the ETC that takes place in the intermembrane space of the mitochondria. One NADH produces 3 ATPs and one FADH2 produces 2 ATPs. With that said, ETC begins with the oxidation of NADH to form NAD+, H+ and 2e-. Through one-way protein pumps and the 2e- from NADH, those H+ protons get trapped on one side and create a gradient. In order to get back into the matrix, they travel through proteins known as ATP synthase, which in turn, generating ATP molecules. The last step of ETC begins with 2e-, H+ and ½ O2 to form water; this process is known as reduction because the electrons are being reduced. Electron Transport Chain ComplexesThe components of the ETC are organized into four large complexes of proteins, often referred to as simply complexes 1,2,3, and 4. Q (coenzyme Q) and the protein cytochrome C act as shuttles that transfer electrons between these complexes. This table lists all the ETC components and what happens at each. Just know generally whatoccurs at each complex.In complex I, NADH is oxidized. In complex II, FADH2 is oxidized. Q transports both of theseto III. In complex III, Q is oxidized. Cytochrome C carries oxidized Q to IV where water is produced. All along this chain, hydrogen is being released to form a gradient.FermentationIf oxygen is lacking or not available at all, the cell will enter fermentation. Rather than transfer pyruvate to the mitochondrion to begin the Krebs cycle, it is reduced to form lactic acid in animal cells and ethanol in plant cells. Essentially the cell is forced to undergoglycolysis more rapidly to produce ATP for the cell.Types of QuestionsWhere things are found. Specific numbers of production. What happens if certain proteinsdon’t work during the process. Proton gradient outside of the membrane.PhotosynthesisGeneral model of a chloroplastTo very briefly summarize the process of photosynthesis, essentially sunlight, water, and CO2 enter and through two stages, these products generate ATP, O2, and glucose. In the first stage, the light dependent phase, sunlight, NADP+ and ATP are used to generate ATP and NADPH via an Electron Transport Chain.General Overview of the Light Dependent Reaction of PhotosynthesisPhotosystem IILight photons from sunlight excite electrons from the oxidized water in photosystem II which forces them along the ETC. They move from photosystem II, to pheophytin, through plastoquinone, then down to photosystem I. More photons hit photosystem I and excites the electron again. It eventually ends as NADPH at a fairly high level of energy.Substrate Level Phosphorylation – production of ATP via an input of carbon molecules and the adhesion of a phosphate group to ADPOxidative Phosphorylation – production of ATP via redox reactions along an ETCCalvin Cycle (Light Independent Reaction)In the light independent stage of photosynthesis, the enzyme RuBisCo uses 3 molecules of RuBP, 6 NADPH, 6 ATP, and 3 molecules of CO2 to produce 6 carbon G3P molecules. Of those 6 G3P molecules, 5 go back to form RuBP and continue the cycle and 1 escapes to begin to form glucose. It takes many turns of the cycle to produce a complete glucose molecule. C3 Photorespiration InefficiencyOne inefficiency about C3 photorespiration is the fact that Rubisco can bind to O2 and because of this, the turning of the Calvin cycle is very inefficient and does not produce as much glucose. C4 and CAM PlantsC4 plants (spatially segregated complexes) and CAM plants (time controlled) have adapted to maximize their light independent reactions. In C4 plants, CO2 is first oxidized by PEP to form Oxaloacetate then moves to form malate. This all occurs within the enzyme PEP Carboxylase. From the mesophyll cells, the malate travels to bundle sheath cells where theregular Calvin cycle resumes. This is all done in an effort to maximize the efficiency of CO2.CAM plants undergo the same cycle as C4 plants yet with CAM plants, they open and closetheir stoma depending on the time of day, to limit the amount of H20 that may escape. They store the malate in vesicles until it can be processed later. MitosisFour stages of the cell-cycleM-Phase (Mitosis)**Note that cytokinesis is not technically a part of mitosis but it usually