Cellular Respiration
Aerobic Respiration
Let’s Review
Anaerobic Respiration:
Does not require Oxygen
Aerobic Respiration:
REQUIRES Oxygen
Name 2 types of Fermentation
1. Alcoholic Fermentation
2. Lactic Acid Fermentation
Where does GLYCOLOSIS occur in the cell?
In the CYTOPLASM
Do you need Oxygen for glycolysis?
NO
Last time…
We discussed that our CELLS need
to produce ATP as a means on
energy to function
We begin this process by breaking
down FOOD MOLECULES such as
GLUCOSE in a process known as
GLYCOLYSIS
In the ABSENCE of oxygen, our cells
perform anaerobic cellular
respiration (FERMENTATION)
Glycolysis
FIRST step in ALL TYPES of cellular Respiration
Breaks down one Molecule of Glucose into 2 molecules of
Pyruvate
Where?: in the CYTOPLASM of the cell
Produces a net amount of ATP
USE 2 ATP to start (-2)
Produces 4 ATP (+4)
4-2= 2 ATP
http://highered.mcgraw-hill.com/sites/0072507470/student_view0/chapter25/animation__how_glycolysis_works.html
Glycolysis: No Oxygen Needed
GLYCOLYSIS
MITOCHONDRIA
INPUTS:
• 1 Glucose
• 2 ATP
OUTPUTS:
• 2 Pyruvates
• 4 ATP (2 net)
CYTOPLASM
Glycolysis
Steps 1 – 3 A fuel
molecule is energized,
using ATP.
Glucose
Step
1
Glucose-6-phosphate
2
Fructose-6-phosphate
3
Energy In: 2 ATP
Fructose-1,6-diphosphate
Step 4 A six-carbon
intermediate splits into
two three-carbon
intermediates.
4
Glyceraldehyde-3-phosphate
(G3P)
5
Step 5 A redox
reaction generates
NADH.
6
Energy Out: 4 ATP
Steps 6 – 9 ATP
and pyruvic acid
are produced.
1,3-Diphosphoglyceric acid
(2 molecules)
7
3-Phosphoglyceric acid
(2 molecules)
8
2-Phosphoglyceric acid
(2 molecules)
2-Phosphoglyceric acid
(2 molecules)
NET 2 ATP
9
Pyruvic acid
(2 molecules
per glucose molecule)
General Outline
Glucose
1. Glycolysis
Pyruvic Acid
Oxygen
Aerobic
2. Krebs Cycle
3. ETC
No Oxygen
Anaerobic
2. Fermentation
Lactic Acid Fermentation
Or
Alcoholic Fermentation
36 ATP
Aerobic Respiration
In AEROBIC respiration, Oxygen is
present
After Glycolysis, the Pyruvates
produced enter the KREBS CYCLE (akaCitric Acid Cycle)
The next step after the Krebs Cycle is
the ELECTRON TRANSPORT CHAIN
General Outline for
Aerobic Respiration
Starts with
Then goes into
Ends in
Net Products
(per 1 glucose molecule)
GLYCOLYSIS
Krebs Cycle (AKACitric Acid Cycle
Electron Transport
Chain
2 Pyruvates
2 ATP
2 ATP
6 NADH
2 FADH
~34 ATP
Pyruvate to Acetyl Co-A
Pyruvate is converted into Acetyl Co-A which
enters the Krebs Cycle
This is done by a series of Redox reactions which involve
the gaining or loss of electrons between NAD+ and
NADH (electron carriers)
LEO the lion says GER
Oxidation reactions are either a REDUCTION
reaction or an OXIDATION reaction
LEO: Lose Electron- Oxidation
GER: Gain Electron- Reduction
When NAD+ gains an H (NADH) it is reduced
When NADH loses an H (NAD+) it is oxidized
Electron Carriers: NADH
and FADH
NADH and FADH are molecules that carry and transfer
ELECTRONS
This transfer of electrons is similar to how electricity
works
Think about how you get electricity to a hair dryer
http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter25/animation__how_t
he_nad__works.html
nd
2
pathway: Krebs Cycle
AKA- Citric Acid Cycle
WHERE? In the MITOCHONDRIA MATRIX
Each Pyruvate activates one
turn in the cycle
Thus, 1 glucose molecule =
2 pyruvates = 2 turns
Products of Krebs:
-CO2
-NADH
-FADH
-ATP
Krebs Cycle Products
For every 1 glucose molecule (i.e- 2 pyruvates) Krebs
produces:
2 ATP (energy!)
6 NADH (???)
2 FADH (???)
4 CO2 (by product)
http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter25/animation__how_t
he_krebs_cycle_works__quiz_2_.html
3rd Pathway: Electron Transport Chain
WHERE?: the INNER MEMBRANE of the Mitochondria
-This is where the MOST ATP is generated
through what we call oxidative phosphorylation
-Electron carriers (NADH) transfer electrons
along the membrane and a proton gradient
forms, fueling the process to create ATP
-the ETC produces between 32-34 ATP molecules
http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter25/animation__electron_transp
ort_system_and_formation_of_atp__quiz_1_.html
Oxidative Phosphorylation
(Chemiosmosis)
Remember, Aerobic Respiration occurs when there is oxygen
present
Role of oxygen comes into play in the Electron Transport
Chain
When the electrons transfer through the membrane, they
eventually get transferred to the Oxygen
When O2 picks electrons up and then forms WATER by
bonding to the H+ protons
Oxygen is the ELECTRON ACCEPTER
ATP Synthase
http://highered.mcgrawhill.com/sites/0072507470/student_view0/chapter25/animation__electron_transport_
system_and_formation_of_atp__quiz_1_.html
Along the Mitochondria’s membrane, there are
proteins aiding in the electron transport process
One Protein is the ATP-making machine (ATP
synthase)
H+ ions pass down through ATP synthase, and allow
the bonding of ADP to P to create ATP
Why do we care? Cyanide
Poisoning
Watch Video
When Cyanide poisoning occurs, it stops the
process of electron transfer at Cytochrome
A3 (right before ATP synthase)
ATP production stops
Build up of Oxygen occurs
Symptoms: flushed, red skin, rapid
breathing, death within minuts
Cell Respiration Song
Because we love science in a song….
Respire to be a Millionaire
http://www.quia.com/rr/216170.html
Summary of Cellular Respiration
Reactions (make sure to know these!)
Aerobic Cellular Respiration:
C6H12O6+ 6O2  6CO2 +6H2O + (36-38ATP)
(remember- it’s the reverse of photosynthesis!)
Anaerobic Cellular Respiration:
Alcoholic Fermentation:
Glucose + (NADH)  Alcohol (i.e- ethanol) + CO2 + 2 ATP
Lactic Acid Fermentation:
Glucose + (NADH)  Lactic Acid + 2 ATP + (NAD+)