Kr ebs cycle and anaerobic respiration
Upcoming SlideShare
Loading in...5
×
 

Kr ebs cycle and anaerobic respiration

on

  • 3,558 views

 

Statistics

Views

Total Views
3,558
Views on SlideShare
3,535
Embed Views
23

Actions

Likes
0
Downloads
33
Comments
1

2 Embeds 23

http://hghshonorsbiology.blogspot.com 17
http://www.hghshonorsbiology.blogspot.com 6

Accessibility

Categories

Upload Details

Uploaded via as Microsoft PowerPoint

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel

11 of 1

  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
  • Please don't equate fermentation with anaerobic respiration. Anaerobic respiration is a microbial process using alternate terminal electron acceptors other than oxygen. Bacteria use anaerobic respiration for oxidative phosphorylation; they just can't get as much ATP as with aerobic respiration.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    Kr ebs cycle and anaerobic respiration Kr ebs cycle and anaerobic respiration Presentation Transcript

    • Krebs Cycle (Citric Acid Cycle)& Quick and Long Energy
    • Glycolysis
      Glucose
      2 molecules of pyruvate
      To the electron transport chain
    • Energy accounting of glycolysis
      2 ATP
      2 ADP
      4 ADP
      2 NAD+
      ATP
      4
      2
      glucose      pyruvate
      6C
      3C
      2x
      All that work! And that’s all I get?
      Butglucose hasso much moreto give!
      Net gain = 2 ATP + 2 NADH
      some energy investment (-2 ATP)
      small energy return (4 ATP + 2 NADH)
      1 6C sugar 2 3C sugars
    • Krebs Cycle
      British biochemist Hans Krebs, discovered 1937
      During Krebs cycle, PYRUVATE is broken down into CARBON DIOXIDE in a series of energy extracting reactions
      AKA the CITRIC ACID CYCLE because citrate (also called citric acid) is the first product of the cycle
    • From Glycolysis comes the Pyruvates….
    • Krebs Cycle
    • Step 1
      Citric Acid Production
      Pyruvate ( 3-carbons) enter mitochondria Matrix
      One carbon is removed as CO2 (WASTE product) and electrons are removed by NAD+ (making NADH which goes to the ETC)
      Co-enzyme A joins the 2-carbon molecule (that used to be pyruvate) making Acetyl-CoA
      Now Acetyl-CoA can enter the Krebs cycle
      Acetyl Co-A combines with 4-carbon molecule called OXALOACETATE , making citrate (citric acid), a 6-carbon molecule
    • Step 2
      Citric acid (6 carbon molecule) is broken down into a few different 5-carbon compounds, then into a few different 4-carbon compounds.
      Each step releases CO2, NADH and FADH2, and ATP
      CO2 is a waste product (breath out!)
      NADH and FADH2 (taxi cabs) goes onto the ETC (where the party is at)
      ATP is used for cell to do work (mechanical, chemical, or transport)
    • 2C
      6C
      5C
      4C
      3C
      4C
      6C
      4C
      4C
      4C
      CO2
      CO2
      Count the carbons!
      acetyl CoA
      pyruvate
      citrate
      oxidationof sugars
      This happens twice for each glucose molecule
      x2
    • 2C
      6C
      5C
      4C
      3C
      4C
      6C
      4C
      4C
      4C
      NADH
      ATP
      CO2
      CO2
      CO2
      NADH
      NADH
      FADH2
      NADH
      Count the electron carriers!
      acetyl CoA
      pyruvate
      citrate
      reductionof electroncarriers
      This happens twice for each glucose molecule
      x2
    • Whassup?
      So we fully oxidized (broke down) glucose
      C6H12O6

      CO2
      & ended up with 4 ATP!
      What’s the point?
    • H+
      H+
      H+
      H+
      H+
      H+
      H+
      H+
      H+
      Electron Carriers = Hydrogen Carriers
      • Krebs cycle produces large quantities of electron carriers
      • NADH
      • FADH2
      • go to Electron Transport Chain!
      ADP+ Pi
      ATP
      What’s so important about electron carriers?
    • 4 NAD+1 FAD
      4 NADH+1FADH2
      2x
      1C
      3x
      1 ADP
      1 ATP
      Energy accounting of Krebs cycle
      pyruvate          CO2
      3C
      ATP
      Net gain = 2 ATP
      = 8 NADH + 2 FADH2
    • Value of Krebs cycle?
      If the yield is only 2 ATP then how was the Krebs cycle an adaptation?
      value of NADH & FADH2
      electron carriers & H carriers
      to be used in the Electron Transport Chain
      like $$in the bank
    • Summary
      In one turn of the Krebs Cycle:
      3 CO2 (1 from right before Krebs)
      Released when we exhale
      1 ATP (E for cell work)
      1 NADH from right before Krebs
      3 NADH from Krebs (to ETC)
      1 FADH2 (to ETC)
      Water leaves and then reenters so we don’t count it in the products
      For one Glucose molecule how many times does the Krebs Cycle turn?
      What are the totals from the Krebs Cycle for one Glucose molecule?
      6 CO2s
      2 ATPs
      8 NADHS
      2 FADH2
    • So we use Krebs if we have oxygen….what if there is NO oxygen???
      Then we can’t even enter the mitochondria and go to the Krebs cycle…
      We are stuck using Glycolysis…
      Anaerobic respiration (NO oxygen)
      2 types
      Lactic acid fermentation
      Alcohol fermentation
    • Pyruvate is a branching point
      O2
      O2
      Pyruvate
      fermentation
      anaerobicrespiration
      mitochondria
      Krebs cycle
      aerobic respiration
    • Glycolysis
      ???
      Pyruvate
      or
      2
    • Cells cannot get enough oxygen
      Build up of pyruvic acid and NADH and no oxygen to break it down
      Cells begin fermentation
      Lactic Acid fermentation
      Pyruvic acid + NADH lactic acid + NAD+
      Get about 90 seconds of energy without having to use oxygen
      HOWEVER, oxygen will be paid back double when you are done (think heavy breathing)
      Occurs in muscle cells, and microorganisms, such as the ones that turn milk into cheese and yogurt
      Lactic acid causes muscle cramping and burning sensation
      Oxygen is required to break down lactic acid and get it out of body
      Alcohol fermentation
      Pyruvic acid + NADH ethyl alcohol + NAD+ + CO2
      Occurs in yeast cells and other microorganisms, such as the ones involved in the production of bread and wine
    • recycleNADH
      How is NADH recycled to NAD+?
      without oxygen
      anaerobic respiration
      “fermentation”
      with oxygen
      aerobic respiration
      Another molecule must accept H from NADH
      pyruvate
      NAD+
      H2O
      CO2
      NADH
      NADH
      O2
      acetaldehyde
      NADH
      acetyl-CoA
      NAD+
      NAD+
      lactate
      lactic acidfermentation
      which path you use depends on who you are…
      Krebs
      cycle
      ethanol
      alcoholfermentation
    • Fermentation (anaerobic)
      pyruvate  ethanol + CO2
      1C
      3C
      2C
      pyruvate  lactic acid
      NADH
      NAD+
      NADH
      NAD+
      3C
      3C
      Bacteria, yeast
      back to glycolysis
      • beer, wine, bread
      • Animals, some fungi
      back to glycolysis
      • cheese, anaerobic exercise (no O2)
    • Alcohol Fermentation
      pyruvate  ethanol + CO2
      1C
      3C
      2C
      NADH
      NAD+
      recycleNADH
      bacteria yeast
      back to glycolysis
      • Dead end process
      • at ~12% ethanol, kills yeast
      • can’t reverse the reaction
      Count thecarbons!
    • Lactic Acid Fermentation
      O2
      pyruvate  lactic acid
      NADH
      NAD+
      3C
      3C
      recycleNADH
      animalssome fungi

      back to glycolysis
      • Reversible process
      • once O2 is available, lactate is converted back to pyruvate by the liver
      Count thecarbons!
    • Quick Energy
      3 ways to obtain energy
      ATP stored in muscles (glycogen) (short)
      ATP from lactic acid (short)
      ATP from cellular respiration (long)
      Cells initially have small amount of ATP from cell resp. and glycolysis
      Think of running a 200 m sprint
      Gun goes off
      Muscles of runner contract, turning glycogen in muscle cells into glucose, but this only provides for a few seconds of intense activity
      You pass the 50m mark
      most ATP the was initially stored is now gone
      Muscle cells are producing ATP from lactic acid fermentation
      This lasts about 90 seconds
      End of Race
      Lots of lactic acid build up
      Only way to get rid of lactic acid is a chemical pathway that requires oxygen
      Thus, at the end of the race, you are breathing heavily and you should follow an intense work out with a slow jog
    • Long Term
      Energy for running long races or other endurance sports
      Cellular respiration is the only way to get enough ATP to last the length of the race
      Cellular respiration makes ATP more slowly than lactic acid fermentation
      Athletes must pace themselves
      Glycogen an important molecule
      Carbohydrate
      Polysaccharide (monosaccharide is glucose)
      Muscle and liver cells store E as glycogen
      Glycogen is broken down by the hormone Glucagon
      Glycogen break down is also stimulated by muscle contraction
      When you work out, muscles contract and they can use energy stored in glycogen
      Increase glycogen storage, increase the duration of exhaustive work your muscles can do
      Stores of glycogen last about 15-20 minutes
      After glycogen is used up, body starts to break down other molecules to get energy
      Fats and proteins
      Fatty acids are broken down and carried to mitochondrial matrix and enter the membrane in fragments as acetyl-CoA
      Proteins are broken down into aa and the these modified aa’s are fed back into the Krebs cycle (NAD+ and FAD)
      Aerobic exercise is good for weight control because it leads to break down of fats
    • Training to Improve Function of ATP production
      Anaerobic training
      Increase levels of glycogen in muscle cells and increase tolerance of lactic acid build up
      Aerobic training
      Increases size and number of mitochondria in muscle cells and increase delivery of oxygen to muscle cells by improving heart and lung efficiency
    • 2007-2008
      What’s thepoint?
      The pointis to makeATP!
      ATP