BIO CH. 6 Notes - My teachers name is Bethanie Michelle Statler and she teaches my biology survey PDF

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My teachers name is Bethanie Michelle Statler and she teaches my biology survey class on Mondays and Wednesdays from 10:00am - 11:40am. ...

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Class Notes 10/9 Chapter 6 How Cells Harvest Chemical Energy Ch. 4-7 Test 6.1 Photosynthesis and cellular respiration provide energy for life - Photosynthesis: the energy of sunlight is used to rearrange the atoms of carbon dioxide and water producing organic molecules and releasing oxygen. - Cellular respiration: O2 is consumed as organic molecules are broken down to CO2 and H2O and the cell captures the energy released in ATP. - Energy ultimately comes from the sun. 6.2 Breathing supplies O2 for use in cellular respiration and removes CO2 - Respiration, as it relates to breathing, and cellular respiration are not the same. - Respiration in the breathing sense refers to an exchange of gases. - Cellular respiration is the aerobic (oxygen-requiring) harvesting of energy from food molecules by cells. 6.3 Cellular respiration banks energy in ATP molecules - Cellular Respiration: - Is an exergonic (energy releasing) process that transfers energy from glucose to form ATP - Can produce up to 32 ATP molecules for each glucose molecule - Uses about 34% of the energy originally stored in glucose with the rest of the energy lost as heat. 6.4 The human body uses energy from ATP for all its activities - Kilocalories: a measure of the quantity of heat required to raise the temperature of 1 kilogram of water by 1 degree celsius. - Your body requires a continuous supply of energy - Cellular respiration provides energy for body maintenance and voluntary activities. 6.5 Cells capture energy from electrons “falling” from organic fuels to oxygen - Redox reaction: the transfer of electrons from one molecule to another is an oxidation reduction reaction. - Oxidation: in a redox reaction the loss of electrons from one substance. - Reduction: addition of electrons to another substance. - NAD+: an important player in the process of oxidizing glucose is a coenzyme which accepts electrons and becomes reduced to NADH. - Electron transport chain: the carrier molecules - How do your cells extract energy from fuel molecules? Transfer of electrons in chemical reactions. - Electrons are removed from fuel molecules and transferred to NAD+ and electron carrier.

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NADH passes electrons to and electron transport chain. Energy is released as electrons “fall” from carrier to carrier and finally to O2.

6.6 Overview: Cellular respiration occurs in three main stages - Stage 1: Glycolysis: occurs in the cytosol of the cell. Glycolysis begins cellular respiration by breaking glucose into two molecules of a three-carbon compound called pyruvate. - Stage 2: Pyruvate oxidation: Citric cycle: take place within the mitochondria. Pyruvate is oxidized to a two-carbon compound. The citric acid cycle then completes the breakdown of glucose to carbon dioxide. - Stage 3: Oxidative phosphorylation: involves electron transport and a process known as chemiosmosis. - NADH and another electron carrier, FADH2, shuttle electrons to electron transport chain embedded in the inner mitochondrial membrane. - Most of the ATP produced by cellular respiration is generated by oxidative phosphorylation. - The electrons are finally passed to oxygen, which reacts to form H2O. - Chemiosmosis: the potential energy of this concentration gradient is used to make ATP. - Of the 3 main stages of cellular respiration, this does not take place in the mitochondria: Glycolysis. 6.7 Glycolysis harvests chemical energy by oxidizing glucose to pyruvate - 2ATP is used to breakdown 1 glucose molecule into 2 G3P. - These 3 carbon intermediates are converted to 2 molecules of pyruvate, yielding a net of 2 ATP and 2 NADH. - ATP is formed by the substrate level phosphorylation in which a phosphate group is transferred from an organic molecule to ADP. - Substrate level phosphorylation: In this process, an enzyme transfers a phosphate group from a substrate molecule to ADP, forming ATP. - Intermediates: Compounds that form between an initial reactant and a final product - Two main phases that group the steps of glycolysis: - 1-4: the energy investment phase, actually consume e  nergy. In this phase, two molecules of ATP are used to energize a glucose molecule, which is then split into two smaller sugars. - 5-9: This phase occurs after glucose has been split into two three-carbon molecules. - Energy Investment Phase: - 1-3: Glucose is energized, using ATP - 4: A 6-carbon intermediate splits into two 3-carbon intermediates. - Energy Payoff Phase: - 5: A redox reaction generates NADH - 6-9: ATP and pyruvate are produced

6.8 After pyruvate is oxidized, the citric acid cycle completes the energy yielding oxidation of organic molecules - The oxidation of pyruvate yields acetyl CoA, CO2, and NADH. - Acetyl CoA: a compound called coenzyme A, derived from the B vitamin, joins with the two-carbon group to form this molecule. - For each turn of the citric acid cycle: - Two carbons from acetyl CoA are released (CO2) - In the end 2 CO2 are released - 1 ATP is produced - 3 NADH and 1 FADH2 are produced (those are electron carriers) - A multienzyme complex catalyzes 3 reactions: - 1. A Carboxyl Group is removed from pyruvate and given off as a molecule of CO2. - 2. The 2 carbon compound remaining is oxidized while a molecule of NAD+ is reduced to NADH. - 3. A compound called coenzyme A, derived from the B vitamin, joins with the two carbon group to form a molecule called acetyl CoA. - If you exposed a mitochondrion to perforins, the outer and inner membrane now have holes in them, but the enzymes are involved in the ETC and ATP synthase are fine, not damaged. Would the mitochondria still consume oxygen? And, would it still produce ATP?: Oxygen is not affected, the ATP (enzymes) are affected, it won’t feel the need to pump protons into the matrix. 6.9 Most ATP production occurs by oxidative phosphorylation - ATP synthase: In the process called chemiosmosis, the resulting concentration gradient drives H+ through this enzyme complex. - In chemiosmosis, the H+ gradient drives H+ back through the enzyme complex ATP synthase (enzyme) in the inner membrane, synthesizing ATP. - In mitochondria, electrons from NADH and FADH2 are passed down the electron transport chain to O2, which picks up H+ into the intermembrane space. - Electrons flow through a series of proteins. - Glucose + Oxygen = Water 6.12 Fermentation enables cells to produce ATP without oxygen - Sometimes oxygen isn’t able to reach your cells so under these conditions: - Glycolysis does not require oxygen. - Glucose is broken down to pyruvate. - When pyruvate is broken down to lactaid/ethanol to produce more ATP while you don’t have oxygen. Cells opt to do these anaerobic processes. - Lactate occurs in muscle - cramps, etc. - Reason: Fermentation is a way of harvesting chemical energy that does not require oxygen. Under anaerobic conditions, muscle cells, yeasts, and certain bacteria produce ATP by glycolysis.

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NAD+ is recycled from NADH as pyruvate is reduced to: - Lactic acid fermentation: Your muscle cells and certain bacteria can regenerate NAD+ by this process - Alcohol fermentation: used in brewing, winemaking, and baking. Yeasts are single-celled fungi that normally use aerobic respiration to process their food. Replenish NAD+ to make at least 2 more ATP. Know the end products.

6.14 Cells use many kinds of organic molecules as fuel for cellular respiration - You obtain most of your calories as: - Carbohydrates (such as sucrose and other disaccharide sugars and starch, a polysaccharide) - Fats - Proteins - Not nucleic acids. - A cell can use these 3 types of molecules to make ATP. - When you eat peanuts the sugar of peanuts can be broken down through glycolysis and the fats in peanuts can be broken down in different parts of the cycle. - Easy for cells to burn down carbohydrates then break down fats to provide energy for your body. How to lose fat. - If someone has an eating disorder the body breaks down carbohydrates then breaks down fats but then you lose enough fat then it’ll break down muscle just to survive....