Chapter 7 - Cellular Respiration Section 7-1 Glycolysis & Fermentation
Jan 22, 2016
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
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15 ? Quiz after
Objective 1: Define cellular respiration
Process of breaking down organic compounds (mainly glucose) to release energy (ATP)
CytosolCytosol
C6H12O6 + 6O2 6CO2 + 6H2O + Energy (ATP)
CytosolCytosol
Starts with glycolysis - the 1st step in cellular respiration
- glucose pyruvic acid (energy) – occurs in cytosol
Objective 2: Describe the major events in glycolysis
(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.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html
1. anaerobic pathways
> absence of oxygenyield no additional
ATPuse 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
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 =
---------- = ________ = _____ %
Efficiency of glycolysis =
Energy required to make ATP
Energy released by oxidation of glucose
Efficiency of glycolysis =
2 X 12 = .035 = 3.5%
686 kcal
7.2 Aerobic Respiration
Section 7-2 Aerobic Respiration
2 major stages, after glycolysis
1. Krebs Cycle
2. 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 CoA3) 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 respiration36 ATP x 12 kcals = 432 kcals/686
kcals = 0.6297 = 63%, nearly 20 times more efficient than anaerobic respiration
63/3.5 = 18