Download Chapter 4 Cellular Respiration

Chapter 4
Cellular Respiration
GCA
Mr. Cobb
Cellular respiration
 Food (glucose) into ATP
 Not “breathing”
 It can be either aerobic or anaerobic
 Aerobic – require oxygen
 Anaerobic – does not require oxygen
3 Stages of
Aerobic Cellular Respiration
 Glycolysis
 Preparation Step &
Citric Acid Cycle (Kreb’s Cycle)
 Electron Transport
Glycolysis
 1st step in aerobic or anaerobic
 Location: cytoplasm of cell
 Glucose
2 Pyruvic Acid molecules
 This process does not require Oxygen.
 Total energy made is 4 ATP, but 2 is needed to start the
rxn. 2 ATP is extra.
 What is made? 2 NADPH, 2 ATP, 2 Pyruvic Acids
Glycolysis
glucose  pyruvate
Glycolysis
Glucose
Pyruvic acid
Pyruvic Acid
Aerobic
 O2 required
 Release H2O and CO2 and energy
 Remember that cellular respiration is the opposite of
photosynthesis.
 C6H1206 + 6 O2
6 CO2 + 6 H2O + ATP
Aerobic Respiration
 Glycolysis is 1st step and in both aerobic or anaerobic
respiration
 2 Steps in Aerobic Respiration:
 2. Citric Acid Cycle or Krebs Cycle
 3. Hydrogen and Electron Transport System
Cellular Respiration Flowchart (aerobic)
Glucose
(C6H1206)
+
Oxygen
(02)
Glycolysis
Krebs
Cycle
Electron
Transport
Chain
Carbon
Dioxide
(CO2)
+
Water
(H2O)
+
ATP
Citric Acid Cycle (Krebs)
 2 Pyruvic acids from glycolysis diffuses into the
mitochondria.
 Pyruvic acid is turned into acetyl CoA and CO2 is
released.
 One glucose molecule makes the cycle turn twice
 Chemical rxns in Mitochondria
 Products: 6 NADH, 2 FADH2, 2 ATP and 4 CO2
Krebs cycle
pyruvate acetyl CoA & CO2
The Krebs Cycle
Section 9-2
Citric Acid
Production
Mitochondrion

H+ and e- transport molecules:
1)
NADH
2)
FADH2
Electron Transport
 NADH and FADH2 from Krebs Cycle are pumped by
electron energy across the inner membrane (cristae)
and creates a concentration difference.
 The H ions come back across through the ATP
synthase and create ATP.
 Oxygen (from what we breathe in) comes in and binds
to the H ions to make water.
Electron Transport
 32 ATP
 Water is made from the Hydrogen and Oxygen.
Electron Transport
Mitochondria
* two membranes
- outer
- inner (folded)
Animation
 http://www.science.smith.edu/departments/Biology/Bio2
31/krebs.html
ELECTRON
TRANSPORT
CHAIN
Mitochondria
H+
H+ e-
eFADH2
NADH
H+
H+
H+
H+
H+
matrix
H+
H+
H+
H+
Electrons
* passed across inner membrane
* their energy gradually decreases
* energy used to transport H+
into the intermembrane space.
electrons
Oxygen
* the final electron acceptor
* joins with H+ to produce H2O.
If there is no oxygen,
the electron chain stops
because there is no way to release electrons .
Mitochondria
H+
H+ e-
eFADH2
NADH
H+
H+
H+
H+
H+
matrix
H+
H+
H+
H+
What happens when there is
no oxygen
to accept the electrons?
* glycolysis done
* then fermentation in cytoplasm
2 kinds
1) lactic acid
2) ethanol
2
6
Products of
Fermentation
fermentation
0 ATP
Just takes e-& H+ off NADH
so glycolysis can continue
Alcoholic Fermentation
After glucose broken down to pyruvate,
then pyruvate broken down
to CO2 and ETHANOL.
Alcoholic Fermentation
by bacteria
& yeast
used to make bread, alcohol,
Lactic Acid fermentation
By human muscle cells
& bacteria
Used to make cheese, yogurt, sour kraut
If you work anaerobically,
fermentation occurs in your muscles
lactic acid builds up
results in
muscle soreness