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1.
2.
3.
4.
Where does glycolysis occur within the cell?
Where does the Krebs cycle occur within the
cell? Need the organelle, and the location
within that organelle.
What is the equation for cellular respiration?
Is cellular respiration catabolic or anabolic?
Introduction and Glycolysis
KEY CONCEPT
The overall process of cellular respiration converts
sugar into ATP using oxygen.
If you would give me 2 dollars and I would give you back
38 dollars would you?
What if you could do this over and over again?
Purpose for Cellular Respiration
◦
Cellular respiration makes ATP by breaking down
organic compounds (carbohydrates and lipids).
◦
Cellular respiration is aerobic, or requires oxygen.
Compare and contrast Aerobic vs. Anaerobic
ENZYMES
C6H12O6 + 6O2  6H2O + 6CO2 + 38 ATP
In cellular respiration is the breakdown of glucose
demonstrating an anabolic or catabolic chemical
reaction?
1.
2.
Anaerobic Respiration
 Glycolysis
Aerobic Respiration
 Krebs Cycle
 The Electron Transport Chain
Requirements For Cellular Respiration
1. Glucose
2. Oxygen (cellular respiration is Aerobic –
requires oxygen)
3. Energy Storing Compounds
◦
◦
◦
NAD+  NADH
FAD  FADH2
ATP
4. Mitochondria

The anaerobic stage of cellular respiration occurs
outside of the Mitochondria, in the cytoplasm

Aerobic respiration takes place in the Mitochondria

Two major parts:
1. Cristae: Folds produced from an inner membrane.
2. Matrix: Contains enzymes used to break organic
compounds.
Glycolysis
Purpose
• Glyco = sugar
• Break glucose into a compound called
Pyruvate.
• Produces energy-storing compounds:
ATP + NADH
Location
• In the cytoplasm of the cell.
• Anaerobic – does not require oxygen
1.
2.
3.
Glucose enters the cell
Glucose is split into 2 three-carbon
molecules.
NAD+ takes electrons, forming NADH and
turning the 2 three-carbon molecules into
Pyruvate.
Products of Glycolysis:
1. Net gain of 2 ATP (2 “spent”, 4 made)
2. NADH
3. 2 Pyruvate


The two pyruvate and the NADH
produced by glycolysis are used for
cellular respiration when oxygen is
present.
NADH is an electron carrier like NADPH
was in photosynthesis.

Cellular respiration has three stages:
◦ Glycolysis (breaks down glucose into two molecules of
pyruvate)
◦ The citric acid cycle (completes the breakdown of
glucose)
◦ Electron Transport Chain(accounts for most of the
ATP synthesis)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
1. Where does it occur?
2. Is it aerobic or anaerobic?
3. What are the products?
4. How does it support evolution?
Fig. 9-8
Energy investment phase
Glucose
2 ADP + 2 P
2 ATP
used
4 ATP
formed
Energy payoff phase
4 ADP + 4 P
2 NAD+ + 4 e– + 4 H+
2 NADH + 2 H+
2 Pyruvate + 2 H2O
Net
Glucose
4 ATP formed – 2 ATP used
2 NAD+ + 4 e– + 4 H+
2 Pyruvate + 2 H2O
2 ATP
2 NADH + 2 H+
A. If OXYGEN is present, the pyruvate will go to
the mitochondria.
B. Before pyruvate can enter the Krebs cycle, it
has to be converted into acetyl CoA.
C. This conversion of pyruvate to Acetyl CoA
produces
◦ 1NADH and 1 carbon dioxide
Remember though, you have 2 pyruvates! What are
the new totals?
Fig. 9-10
CYTOSOL
MITOCHONDRION
NAD+
NADH + H+
2
1
Pyruvate
Transport protein
3
CO2
Coenzyme A
Acetyl CoA
Purpose:
To completely breakdown Acetyl CoA in order
to produce NADHs and FADH2 that can be
taken to the ETC. (Money in the bank)
Where:
The mitochondrial matrix
Important: Will only occur if oxygen is present
Fig. 9-11
Pyruvate
CO2
NAD+
CoA
NADH
+ H+
Acetyl CoA
CoA
CoA
Citric
acid
cycle
FADH2
2 CO2
3 NAD+
3 NADH
FAD
+ 3 H+
ADP + P i
ATP

For every pyruvate that goes in you get:
◦ 1 ATP
◦ 1 FADH2
◦ 3 NADH
But, for each glucose you get two pyruvates,
therefore you would have to double your numbers.
Krebs will produce:
2 ATP
2 FADH2
6 NADH




Team Glycolysis: 2 ATP
Team Transition Step: 0 ATP
Team Krebs Cycle: 2 ATP
We need 38 ATP, we only have 4…where in
the world do we get all that ATP?




Team Glycolysis: 2 NADH
Team Transition Step: 2 NADH
Team Krebs Cycle: 6 NADH and 2 FADH2
Time to utilize the energy from the electrons
taken from glucose to produce massive
amounts of ATP!



Purpose: To harvest energy from electrons to
produce large amounts of ATP
Where: The cristae of the mitochondrion. The
inner-membrane.
Important: Will not occur without oxygen
A. NADH and FADH2 will go to the ETC and
drop off its electrons into the chain.
B. As the electrons fall through the transport
chain, energy is harvested and used to
make ATP. (ADP to ATP, recharge the
batteries)
C. Oxygen accepts electrons at the end of the
chain and forms a water molecule.
A. Without oxygen the ETC would not work.
B. Due to oxygen being highly electronegative
(electron hog) it is what pulls the electrons
through the ETC allowing the production
of ATP. This is why the process is
AEROBIC.
C. After oxygen accepts electrons it will bind to
2 hydrogens and form water.
A. Our cells control the fall of electrons in
many small steps so the process can be more
efficient.
Looking at the drawing on the board, why do
our cells not allow the electrons to react with
oxygen in one big step?
Fig. 9-5
H2 + 1/2 O2
2H
(from food via NADH)
Controlled
release of
+
–
2H + 2e
energy for
synthesis of
ATP
1/
2 O2
Explosive
release of
heat and light
energy
1/
(a) Uncontrolled reaction
(b) Cellular respiration
2 O2
Fig. 9-6-1
Electrons
carried
via NADH
Glycolysis
Pyruvate
Glucose
Cytosol
ATP
Substrate-level
phosphorylation
Fig. 9-6-2
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Citric
acid
cycle
Glycolysis
Pyruvate
Glucose
Mitochondrion
Cytosol
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Fig. 9-6-3
Electrons carried
via NADH and
FADH2
Electrons
carried
via NADH
Citric
acid
cycle
Glycolysis
Pyruvate
Glucose
electron transport
Mitochondrion
Cytosol
ATP
ATP
ATP
Substrate-level
phosphorylation
Substrate-level
phosphorylation
Oxidative
phosphorylation