Bios 208 1st EditionExam # 5 Study GuideI. RespirationA. Living cells require energy from outside sourcesB. Some animals,(e.g. primates), obtain energy by eating plants, and some animals feed on other organisms that eat plantsC. Energy flows into an ecosystem as sunlight and leaves as heatD. Photosynthesis generates O2 and organic molecules, which are used in cellular respirationE. Cells use chemical energy stored in organic molecules to regenerate ATP, which powers workF. Several processes are central to cellular respiration and related pathways…glycolysis, Krebs cycle, electron transport.G. The breakdown of organic molecules is exergonicH. Fermentation is a partial degradation of sugars that occurs without O2 produces ethanol or lactic acid.I. Aerobic respiration consumes organic molecules and O2 and yields ATP…produces CO2J. Anaerobic respiration is similar to aerobic respiration but consumes compounds other than O2K. Cellular respiration includes both aerobic and anaerobic respiration but is often used to refer to aerobic respirationL. Although carbohydrates, fats, and proteins are all consumed as fuel, it is helpful to trace cellular respiration with the sugar glucoseM. C6H12O6 + 6 O2  6 CO2 + 6 H2O + Energy (ATP + heat)N. Energy is needed for motility, solute transport, and chemical reactions, among others.O. The target is “energized” by the temporary attachment of a phosphate group (phosphorylation).P. Removing the phosphate (dephosphorylation) releases the E needed for the reactionII. Krebs cycle A. The citric acid cycle, also called the Krebs cycle, completes the breakdown of pyruvateto CO2.B. The cycle oxidizes organic fuel derived from pyruvate, generating 1 ATP, 3 NADH, and 1 FADH2 per turn.C. The citric acid cycle has eight steps, each catalyzed by a specific enzyme. D. The acetyl group of acetyl CoA joins the cycle by combining with oxaloacetate, forming citrate. E. The next seven steps decompose the citrate back to oxaloacetate, making the processa cycle.F. The NADH and FADH2 produced by the cycle relay electrons extracted from food to the electron transport chain.G. In the presence of O2, pyruvate enters the mitochondrion (in eukaryotic cells) where the oxidation of glucose is completed.H. Before the citric acid cycle can begin, pyruvate must be converted to acetyl CoenzymeA (acetyl CoA), which links glycolysis to the citric acid cycle.I. This step is carried out by a multi-enzyme complex that catalyses’ three reactions.J. The next seven steps decompose the citrate back to oxaloacetate, making the processa cycleK. The NADH and FADH2 produced by the cycle relay electrons extracted from food to the electron transport chainL. Cycle of 8 reactions.M. Occurs in the mitochondrial matrixN. 2 turns per glucoseO. Net reaction per glucoseP. Citric Acid Cycle (a.k.a. Krebs cycle or TCA cycle)Q. Reactants:a) 2 acetyl-CoAb) 2 ADPc) 6 NAD+d) 2 FADR. Products:a) CO2b) 2 ATPc) 6 NADHd) 2 FADH2S. 2 turns of the cycle per glucoseT. Reaction #1: Oxaloacetate (4C) + acetyl (2C) citrate (6C)U. oxidation reactions yield lots of reducing power:a) NADH +1FADH2 per acetyl-CoA;b) 6 NADH + 1 FADH2 per glucose)V. 1 ATP is made by SLP (involves a GTP intermediate)W. Following glycolysis and the citric acid cycle,X. NADH and FADH2 account for most of the energy extracted from foodY. These two electron carriers donate electrons to the electron transport chain, which powers ATP synthesis via oxidative phosphorylationZ. Making ATP (Oxidative Phosphorylation) is complicated. It requires:a) reducing power;b) a proton gradient;c) an electron transport chain;d) oxygene) many other factors. But, the ATP yield is HUGE.III. Mitochondrial electron TransportA. Mitochondria: Site of cell respiration (oxidative phosphorylation). O2 is used to breakdown food and make ATP. Mitochondria occur in nearly all eukaryotic cells.B. Basic featuresC. Inner membrane (from bacterial Plasma Membrane): contains an ETC (electron transportchain); in foldings are cristae.D. Outer membrane (from host Plasma Membrane).E. Matrix (from cytoplasm of bacterial cell): contains ribosomes, DNA, Krebs cycle enzymes.F. Mitochondria and chloroplasts change energy from one form to another.G. Mitochondria are the sites of cellular respiration, a metabolic process that uses oxygen to generate ATP.H. Chloroplasts, found in plants and algae, are the sites of photosynthesis.I. Peroxisomes are oxidative organelles.IV. Fermentation ReactionsA. Fermentation consists of glycolysis plus reactions that regenerate NAD+, which can be reused by glycolysisB. Two common types are alcohol fermentation and lactic acid fermentationC. In alcohol fermentation, pyruvate is converted to ethanol in two steps, with the first releasing CO2D. Alcohol fermentation by yeast is used in brewing, winemaking, and bakingE. In lactic acid fermentation, pyruvate is reduced to NADH, forming lactate as an end product, with no release of CO2F. Lactic acid fermentation by some fungi and bacteria is used to make cheese and yogurtG. Human muscle cells use lactic acid fermentation to generate ATP when O2 is scarceH. Obligate anaerobes carry out fermentation or anaerobic respiration and cannot survive in the presence of O2I. Yeast and many bacteria are facultative anaerobes, meaning that they can survive using either fermentation or cellular respirationJ. In a facultative anaerobe, pyruvate is a fork in the metabolic road that leads to two alternative catabolic routesV. PhotosynthesisA. Photosynthesis is the process that converts solar energy into chemical energy directly or indirectly, photosynthesis nourishes almost the entire living worldB. Autotrophs sustain themselves without eating anything derived from other organismsC. Autotrophs are the producers of the biosphere, producing organic molecules from CO2 and other inorganic moleculesD. Almost all plants are photoautotrophs, using the energy of sunlight to make organic moleculesE. Photosynthesis occurs in plants, algae, certain other protists, and some prokaryotesF. These organisms feed not only themselves but also most of the living worldG. Heterotrophs obtain their organic material from other organismsH. Heterotrophs are the consumers of the biosphereI. Almost all heterotrophs, including humans, depend on photoautotrophs for food and O2J. The Earth’s supply of fossil fuels was formed from the remains of organisms that died hundreds of millions of years agoK. In a sense, fossil fuels represent stores