Title: Cellular Respiration: Harvesting Chemical Energy
1Cellular Respiration Harvesting Chemical Energy
2Respiration is the process of extracting stored
energy from glucose and storing it in the high
energy bonds of ATP.
3Cellular Respiration Equation
Reactants
Products
- C6H12O6 6 O2 6 CO2 6 H2O
and energy - As a result of respiration, energy is released
from the chemical bonds and used for
phosphorylation of ATP. - Phosphorylation is the process of adding a
phosphate group to a molecule. By adding a
phosphate ADP it becomes ATP. - The respiration reactions are controlled by
ENZYMES.
4Cellular Respiration
- There are two types of Respiration Anaerobic
Respiration and Aerobic Respiration - Some organisms use the Anaerobic Respiration
pathway, and some organisms use the Aerobic
Respiration pathway.
5Anaerobes
- Anaerobes are organisms that use the Anaerobic
Respiration pathway - Most anaerobes are bacteria (not all).
- Anaerobes do NOT require oxygen.
6Aerobes
- Aerobes are organisms that use the Aerobic
Respiration pathway. - Aerobes require oxygen.
7Anaerobic Respiration
- Anaerobic Respiration does
- NOT require oxygen!
- The 2 most common forms of Anaerobic Respiration
are - 1. Alcoholic Fermentation, and
- 2. Lactic Acid Fermentation
8The First Stage of Respiration for ALL living
organisms, anaerobes or aerobes, is called
Glycolysis and takes place in the Cytosol.
9Glycolysis
- glyco means glucose/sugar, and
- lysis means to split. Therefore,
- glycolysis means to split glucose
- This process was likely used to supply energy for
the ancient forms of bacteria.
10Glycolysis
- Function - to split glucose and produce NADH, ATP
and Pyruvate (pyruvic acid). - Location - Cytosol
- Occurs in 9 steps- 6 of the steps use magnesium
(Mg) as a cofactor.
11Glycolysis
4 ATPs are produced
Pyruvic Acid (3 Carbons)
Glucose (6 carbons)
2 ATPs supply the activation energy
Pyruvic Acid (3 Carbons)
2 NAD 2 e- 2 NADH
4 ATP Yield 2 ATP Net Gain
12Products of Glycolysis
- 2 Pyruvic Acids (a 3C acid)
- 4 ATP
- 2 NADH
13Alcoholic Fermentation
- is carried out by yeast,
- a kind of fungus.
14Alcoholic Fermentation
- Uses only Glycolysis.
- Does NOT require O2
- Produces ATP when O2 is not available.
15Alcoholic FermentationC6H12O6
2 C2H5OH 2 CO2
(Ethyl Alcohol or Ethanol)
As a result of Alcoholic Fermentation, Glucose
is converted into 2 molecules of Ethyl Alcohol
and 2 Molecules of Carbon Dioxide.
16Alcoholic Fermentation
Glycolysis
Released into the environment
4 ATPs are produced
CO2
(C2H5OH)
Pyruvic Acid (3C)
Ethyl Alcohol (2C)
Glucose (6 carbons)
Released into the environment
CO2
Pyruvic Acid (3C)
2 ATPs supply the activation energy
Ethyl Alcohol (2C)
(C2H5OH)
2 NAD 2 e- 2
NADH 2 NAD 2 e-
4 ATP Yield 2 ATP Net Gain
17Question
- Why is the alcohol content of wine always around
12-14? - Because Alcohol is toxic and kills the yeast at
high concentrations. - Oh Yeah..The Holes in Swiss Cheese are bubbles
of CO2 from fermentation.
18 Importance of Fermentation
- Alcohol Industry - almost every society has a
fermented beverage. - Baking Industry - many breads use yeast to
provide bubbles to raise the dough.
19Lactic Acid Fermentation
- Uses only Glycolysis.
- Does NOT require O2
- Produces ATP when O2 is not available.
20Lactic Acid Fermentation
- Carried out by human muscle cells under oxygen
debt. - Lactic Acid is a toxin and causes fatigue,
soreness and stiffness in muscles.
21Lactic Acid Fermentation
Glycolysis
4 ATPs are produced
Pyruvic Acid (3C)
Lactic Acid (3C)
Glucose (6 carbons)
Pyruvic Acid (3C)
2 ATPs supply the activation energy
Lactic Acid (3C)
2 NAD 2 e- 2
NADH 2 NAD 2 e-
4 ATP Yield 2 ATP Net Gain
22Fermentation - Summary
- Releases 2 ATP from the breakdown of a glucose
molecule - Provides ATP to a cell even when O2 is absent.
23Aerobic Respiration
- Aerobic Respiration
- requires oxygen!
24There are three phases to Aerobic Respiration ...
they are
- 1. Glycolysis (same as the glycolysis of
anaerobic respiration) - 2. Krebs cycle (AKA - Citric Acid cycle)
- 3. Oxidative Phosphorylation and The Electron
Transport Chain
25Phase One Glycolysis(takes place in the
cytoplasm)
Glycolysis
4 ATPs are produced
Pyruvic Acid (3C)
Glucose (6 carbons)
Pyruvic Acid (3C)
2 ATPs supply the activation energy
2 NAD 2 e- 2
NADH
4 ATP Yield 2 ATP Net Gain
26- In order for Aerobic Respiration to continue the
Pyruvic acid is first converted to Acetic Acid by
losing a carbon atom and 2 oxygens as CO2. - The Acetic acid then must enter the matrix region
of the mitochondria. The CO2 produced is the CO2
animals exhale when they breathe.
27Phase Two The Krebs Cycle(AKA the Citric Acid
Cycle)
Once the Acetic Acid enters the Matrix it
combines with Coenzyme A to form a new molecule
called Acetyl-CoA. The Acetyl-CoA then enters the
Krebs Cycle.
CoA breaks off to gather more acetic acid. The
Acetic acid is broken down.
Sir Hans Adolf Krebs
Produces most of the cell's energy in the form of
NADH and FADH2 not ATP Does NOT require O2
3H
3 NADH
28- Summary
- As a result of one turn of the Krebs cycle the
cell makes - 1 FADH2
- 3 NADH
- 1 ATP
- However, each glucose produces two pyruvic acid
molecules. So the total outcome is - 2 FADH2
- 6 NADH
- 2 ATP
29Comparing Aerobic and Anaerobic Respiration
- Aerobic Respiration-
- requires a mitochondrion and oxygen
- is a three phase process
- Anaerobic
- does not require oxygen
- consists of one phase only-Glycolysis
30Strict vs. Facultative Respiration
- Strict - can only carry out Respiration only
one way aerobic or anaerobic. Ex - you - Facultative - can switch respiration types
depending on O2 availability. Ex yeast - Aerobes organisms that require oxygen
- Anaerobes - organisms that DO NOT require oxygen
- Obligate Anaerobes oxygen is LETHAL to these
organisms - Facultative organisms that can live with or
without oxygen
31ATP Sum
- 10 NADH x 3 30 ATPs
- 2 FADH2 x 2 4 ATPs
- 2 ATPs (Gly) 2 ATPs
- 2 ATPs (Krebs) 2 ATPs
- Max 38 ATPs per glucose
32However...
- Some energy (2 ATPs) is used to shuttle the NADH
from Glycolysis into the mitochondria..So, some
biologists teach there is an actual ATP yield of
36 ATPs per glucose.