Exam 3 Study Guide

Exam 3 Study Guide - Chapter 8 Harvesting Energy:...

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Chapter 8 Harvesting Energy: Glycolysis and Cellular Respiration Vocabulary acetyl Co-A coenzyme A aerobic using oxygen anaerobic not using oxygen cellular respiration the oxygen-requiring reactions, occurring in mitochondria, that break down the end products of glycolysis into carbon dioxide and water while capturing large amounts of energy as ATP. electron transport chain fermentation anaerobic reactions that convert the pyruvic acid produced by glycolysis into lactic acid or alcohol and carbon dioxide. glucose activation glycolysis reactions, carried out in the cytoplasm, that break down glucose into two molecules of pyruvic acid, producing two ATP molecules; does not require oxygen but can proceed when oxygen is present. Krebs cycle a cyclic series of reactions, occurring in the matrix of mitochondria, in which the acetyl groups from the pyruvic acids produced by glycolysis are broken down to accompanied by the formation of ATP and electron carriers; also called citric acid cycle. Matrix the fluid contained within the inner membrane of a mitochondrion. NADH “energized” carrier molecule pyruvate a three-carbon molecule that is formed by glycolysis and then used in fermentation or cellular respiration. Things to Know: 1. During complete glucose metabolism, what percent of the energy is captured and stored in ATP? Why isn’t all of the energy in glucose stored in ATP? 2 nd law of thermodynamics: conversion of energy into different forms always results in the decrease of the amount of concentrated, useful energy. Cells are extremely efficient at capturing chemical energy, trapping about 40% of energy in glucose. 2. What is the first step in glucose breakdown? Where does it take place? List the products of this first step. -Glycolysis is the first step, does not require oxygen and proceeds in exactly the same way under both aerobic and anaerobic conditions. -takes place in the cytoplasm -glycolysis splits apart a single glucose molecule (a six-carbon sugar)into two three- carbon molecules of pyruvate ; this splitting releases a small fraction of the chemical energy sotred in glucose, some of which is used to generate a net output of two ATP molecules and two NADH molecules 3. If oxygen is absent, what process follows glycolysis? If oxygen is present, what process follows glycolysis? -if oxygen absent: the pyruvate is converted by fermentation into lactate or ethanol; no ATP from fermentation -if oxygen present: cellular respiration uses oxygen to break pyruvate down completely to carbon dioxide and water, generating 34-36 ATP molecules 1
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-in absence of oxygen, pyruvate accepts electrons from NADH, producing ethanol or lactate (fermentation -in presence of oxygen, oxygen becomes the electron acceptor, allowing pyruvate to be fully broken down and its energy harvested as ATP (cellular respiration) 4. You should know the products of the 2 types of fermentation and what types of cells will carry out these processes. 1. one type converts pyruvate to lactate (ionized form of lactic acid in solution in
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Exam 3 Study Guide - Chapter 8 Harvesting Energy:...

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