Cellular Respiration and Fermentation - PowerPoint PPT Presentation

Loading...

PPT – Cellular Respiration and Fermentation PowerPoint presentation | free to download - id: 80cbb8-ZDk2M



Loading


The Adobe Flash plugin is needed to view this content

Get the plugin now

View by Category
About This Presentation
Title:

Cellular Respiration and Fermentation

Description:

Title: Cellular Respiration Last modified by: megan.conner Created Date: 2/1/2006 6:13:37 PM Document presentation format: On-screen Show (4:3) Company – PowerPoint PPT presentation

Number of Views:44
Avg rating:3.0/5.0
Slides: 24
Provided by: weeblyCom
Learn more at: http://mabescience.weebly.com
Category:

less

Write a Comment
User Comments (0)
Transcript and Presenter's Notes

Title: Cellular Respiration and Fermentation


1
Cellular Respiration and Fermentation
  • Chapter 9
  • Unit 3

2
Catabolic Pathways
  • Fermentation
  • Partial breakdown of sugars
  • anaerobic
  • Cell Respiration
  • Most prevalent and efficient
  • Complete breakdown of sugars
  • aerobic

3
Redox Reactions Oxidation and Reduction
  • Transfer of e- from one reactant to another
  • Oxidation loss of electrons
  • Reduction addition of electrons to another
    substance
  • Reducing agent electron donor (C6H12O6)
  • Glucose reduces oxygen which accepts the e-
  • Oxidizing agent electron acceptor (6O2)
  • Oxidizes glucose by accepting the e-

C6H12O6 6O2 ? 6H2O 6CO2
4
Energy Harvest via NAD
  • Energy is released as electrons fall from
    organic molecules to O2
  • Broken down into steps
  • Coenzyme NAD electron acceptor
  • NAD picks up 2e- and 2H ? NADH (stores E)
  • NADH carries electrons to the electron transport
    chain (ETC)
  • ETC transfers e- to O2 to make H2O releases
    energy

5
Substrate-Level Phosphorylation
  • Phosphorylation enzyme transfers a phosphate
    from a substrate to ADPother compounds
  • Mode of ATP synthesis
  • ADP Pi ? ATP

6
Stages of Cellular Respiration
  • Glycolysis
  • Pyruvate oxidation and krebs
  • Oxidative Phosphorylation ETC and chemiosmosis

7
Glycolysis
  • sugar splitting
  • Believed to be ancient (early prokaryotes)
  • Occurs in cytosol
  • Partially oxidizes glucose (6C) to 2 pyruvates
    (3C)
  • Net gain 2 ATP 2NADH
  • Also makes 2H2O
  • Anaerobic

8
Occurs in two Phases
  • Energy-investment phase uses two molecules of
    ATP (5 steps)
  • Energy yielding phase produces four ATP
    molecules and reduces two molecules of NAD to
    NADH
  • The junction between Glycolysis and the Krebs
    cycle is the oxidation of pyruvate to acetyl CoA.
  • two acetyl fragments are produced

9
(No Transcript)
10
Mitochondrion Structure
Citric Acid Cycle (matrix)
ETC (inner membrane)
11
Oxidation of Pyruvate
  • Eukaryote-gt mitochondria
  • Prokaryotes-gt cytosol
  • Pyruvate is converted to coenzyme A (acetyl CoA)

12
Krebs Cycle (Citric acid cycle)
  • Occurs in the mitochondrial matrix
  • aerobic
  • Completes glucose oxidation by breaking down
    acetyl CoA into 3 molecules of carbon dioxide
  • Net gain 2 ATP, 6 NADH, 2 FADH2

13
(No Transcript)
14
Krebs cycle Evolution
  • Evolved later than glycolysis
  • bacteria ?3.5 billion years ago (glycolysis)
  • free O2 ?2.7 billion years ago (photosynthesis)
  • eukaryotes ?1.5 billion years ago (aerobic
    respiration organelles ? mitochondria)

Hans Krebs 1900-1981
15
The Electron Transport Chain
  • electron-carrier molecules built into the inner
    mitochondrial membrane
  • Does not make ATP directly
  • Eases the fall of e- from food to oxygen
  • Oxygen final electron acceptor

16
Sequence of electron transfers along the electron
transport chain
17
Chemiosmosis
  • ATP production
  • This is accomplished by creating a proton
    gradient
  • ATP synthase
  • Cristae

18
How chemiosmosis works
  • the electron transport chain creates the proton
    gradient by pumping H from the mitochondrial
    matrix
  • the membranes phospholipid bilayer is
    impermeable to Hs and prevents back flow
  • As protons diffuse through the ATP synthase
    complex phosphorylation of ADP occurs

19
Anaerobic Respiration
  • Prokaryotes who live in environments w/o Oxygen
  • Generate ATP using other electron acceptors
    besides O2
  • EX sulfur reducing bacteria use sulfate ions at
    the end of their ETC
  • Hydrogen sulfide is produced
  • Rotten egg odor in salt marshes or mud flats

20
Types of Fermentation
  • Extension of glycolysis that allows continuous
    generation of ATP
  • Types
  • Alcoholic Fermentataion
  • Pyruvate is converted to ethanol
  • CO2 is released as it is converted to
    acetaldehyde
  • Acetaldehyde is reduced by NADH to ethanol
  • Regenerates NAD needed for glycolysis

21
  • Lactic Acid Fermentation
  • Pyruvate is reduced by NADH to form lactate as an
    end product
  • Lactate that accumulates in muscle cells was
    thought to cause muscle fatigue and pain, but now
    it is suggested that pain comes from increased
    levels of K
  • Lactate appears to enhance muscle performance
  • Lactate is carried by the blood to the liver
    where it is converted back to pyruvate.

22
Anaerobes
  • Obligate Anaerobes carry out fermentation or
    anaerobic respiration
  • Cannot survive in presence of Oxygen
  • EX vertebrate brain cells cannot carry out
    fermentation
  • Facultative Anaerobes use either fermentation or
    respiration
  • Consumes more sugar when fermenting than
    respiring to make same amt. of ATP
  • EX yeast, bacteria, muscle cells

23
Glycolysis
O2 present
Without O2
  • Fermentation
  • Respiration
  • Keep glycolysis going by regenerating NAD
  • Occurs in cytosol
  • No oxygen needed
  • Creates ethanol CO2 or lactate
  • 2 ATP (from glycolysis)
  • Release E from breakdown of food with O2
  • Occurs in mitochondria
  • O2 required (final electron acceptor)
  • Produces CO2, H2O and up to 32 ATP
About PowerShow.com