Chapter 7 - Cellular Respiration Section 7-1 Glycolysis & Fermentation

Intro Video - 40 min http://10.20.0.2/videos/pmp/videos/wm/1MB/72831-HAVT_1Mb.wmv Fill in notes 15 ? Quiz after

Objective 1: Define cellular respiration Process of breaking down organic compounds (mainly glucose) to release energy (ATP) Cytosol Cytosol

C6H12O6 + 6O2  6CO2 + 6H2O + Energy (ATP) Cytosol Cytosol

Objective 2: Describe the major events in glycolysis Starts with glycolysis - the 1st step in cellular respiration - glucose  pyruvic acid (energy) – occurs in cytosol

(see 7-1 ARG) Each glucose  2 ATP (energy), 2 NADH (energy), & 2 pyruvic acid Net 2 ATP b/c 2 used in step 1 Pyruvic acid takes 1 of 2 pathways:

http://highered. mcgraw-hill http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html

1. anaerobic pathways > absence of oxygen yield no additional ATP use by many unicellular, some multicellular > ex. Fermentation

2. aerobic respiration > oxygen is present > produces considerable amount of ATP

Objective 3: Compare and contrast lactic acid fermentation and alcoholic fermentation (p.129) both are processes that… follow glycolysis, so use pyruvic acid occur w/ little or no oxygen (O2) produce no ATP regenerate NAD+ (electron acceptor) for step 3 of glycolysis

Contrasts: lactic acid alcoholic muscle cells, fungi, & bacteria Type of cells muscle cells, fungi, & bacteria plant cells and fungi (yeast) Products 3-C lactic acid 2-C ethyl alcohol By-products leads to muscle fatigue/pain releases CO2 Uses used to make yogurt & cheese used to make wine, beer, bread

Objective 4: Calculate the efficiency of glycolysis (p. 131) kilocalorie (kcal) – unit of energy measurement; = 1,000 calories It takes 12 kcals to make each ATP molecule

In glycolysis, ____ ATP are produced; this requires ____ kcals The oxidation of glucose releases 686 kcals

Efficiency of glycolysis = Energy required to make ATP Energy released by oxidation of glucose ---------- = ________ = _____ %

Efficiency of glycolysis = Energy required to make ATP Energy released by oxidation of glucose 2 X 12 = .035 = 3.5% 686 kcal

7.2 Aerobic Respiration

Section 7-2 Aerobic Respiration 2 major stages, after glycolysis Krebs Cycle Electron Transport Chain (ETC) http://10.20.0.2/videos/1/10621/chp892400_1000k.wmv

Objective 5: Summarize the events of the Krebs cycle (see ARG 7-2) What happens between glycolysis and the Krebs cycle? Pyruvic acid: 1) enters matrix (space inside inner membrane) 2) reacts w/ CoA to form acetyl CoA 3) other carbon is released as carbon dioxide gas, CO2

Objective 6: Summarize the events of the electron transport chain (ETC)

- NADH and FADH2 (from Krebs cycle) provide electrons

- electron energy pumps hydrogen ions (H+) out of matrix & lose energy > builds up H+’s between 2 membranes

- H+’s diffuse back into matrix through membrane protein, ATP synthase > energy used to make up to 34 ATP from ADP & P; process called chemiosmosis

- final electron acceptor is oxygen, which also accepts protons (H+); forms water

Aerobic Respiration

Objective 7: Relate aerobic respiration to the structure of a mitochondrion - Matrix contains enzymes that catalyze rxns. of Krebs cycle - inner folded membrane has large surface area for ETC – Prokayotes in cell membrane

- proteins in inner membrane used as: 1) pumps to move H+’s & NADH (uses 2 ATP) out of inside the inner membrane 2) enzymes that catalyze chemiosmosis

Objective 8: Calculate the efficiency of aerobic respiration 36 ATP x 12 kcals = 432 kcals/686 kcals = 0.6297 = 63%, nearly 20 times more efficient than anaerobic respiration 63/3.5 = 18