Cellular
Respiration
What Is ATP?
Energy used by all Cells
Adenosine Triphosphate
Organic molecule containing highenergy Phosphate bonds
Copyright Cmassengale
ATP for energy
ATP powers cellular work- made in photosynthesis
and cellular respiration
 A cell does three main kinds of work:
 Mechanical work, beating of cilia, contraction of
muscle cells, and movement of
chromosomes(produces heat)
 Transport work, pumping substances across
membranes against the direction of spontaneous
movement
 Chemical work, driving endergonic reactions such
as the synthesis of polymers from monomers
High Energy Electrons and Molecules
Electron Carrier: a molecule that picks up the
electron and uses this energy to break
apart bonds.
Examples of electron carriers: NADP and ATP
NADP captures two electrons of H and
becomes NADPH.
ADP becomes ATP!!!
How Does ATP Work?






So what?
Energy is stored in these bonds.
So?
The breaking of the chemical bond releases the
energy
ATP + H2O→ ADP + P + ENERGY
ATP is made in photosynthesis and
respiration!!!
ATP (adenosine triphosphate) is a a molecule that
carries energy that cells can use.
How Does ATP Work?


The bonds between phosphate groups can be
broken by hydrolysis which produces
energy!!!
ATP has 3 phosphate groups The bond to the
third bond is easily broken. When the third
bond is broken, energy is released. Becomes
ADP – no energy!!
Chemical Structure of ATP
Adenine Base
3 Phosphates
Ribose Sugar
Copyright Cmassengale
What Does ATP Do for You?
It supplies YOU with ENERGY!
Copyright Cmassengale
How Do We Get Energy From ATP?
By breaking
the highenergy
bonds
between the
last two
phosphates
in ATP
Copyright Cmassengale
What is the Process Called?
HYDROLYSIS (Adding H2O)
H 2O
Copyright Cmassengale
How Does That Happen?
An
Enzyme!
Copyright Cmassengale
How is ATP Re-Made?
The reverse of the previous
process occurs.
Another Enzyme is
used!
ATP Synthase
Copyright Cmassengale
The ADP-ATP Cycle
ATP-ase
ATP
Synthase
Copyright Cmassengale
When is ATP Made in the Body?
During a
Process
called
Cellular
Respiration
that takes
place in both
Plants &
Animals
Copyright Cmassengale
Cellular Respiration
The
process in
which cells
turn food into
usable
energy in the
form of ATP.
Cellular Respiration
RELEASES CHEMICAL ENERGY
FROM SUGARS AND OTHER
CARBON-BASED MOLECULES TO
MAKE ATP WHEN OXYGEN IS
PRESENT!!!!
NO OXYGEN – FERMENTATION!!!!
The Purpose of Cellular Respiration
It is to make and break bonds to generate ATP and
electrons.
You end up with ATP, H ions and electrons.
The electrons are sent to the Electron Transport Chain
where they help to make ATP through ATP synthase.
****Hydrogen ions are bonded with oxygen to make
water which is used in photosynthesis.
Cellular Respiration Overview



Transformation of chemical energy in food into
chemical energy cells can use: ATP
These reactions proceed the same way in plants
and animals. Process is called cellular
respiration
Overall Reaction:
–
C6H12O6 + 6O2 → 6CO2 + 6H2O
Overall Equation for Cellular
Respiration
C6H12O6 + 6O2
YIELDS
6CO2 + 6H20 + e- + 36-38ATP’s
What are the Stages of Cellular
Respiration?
Glycolysis
The
Krebs Cycle
The Electron Transport Chain
Copyright Cmassengale
Cellular Respiration



Glycolysis – Occurs before Cell. Resp.
Krebs Cycle (Citric Acid Cycle)
Electron Transport Chain (ETC)
Glucose
Glycolysis
Krebs
cycle
Fermentation
(without oxygen)
Electron
transport
Alcohol or
lactic acid
Overall Reaction
C6H12O6 + 6O2 → 6CO2 + 6H2O + 38 ATP
Overall this is a three stage process
Glycolysis: before cellular respiration

1.
•
•
Occurs in the cytoplasm
Glucose is broken down
Krebs Cycle
2.
•
•
Breaks down pyruvate into CO2
Occurs in mitochondrial matrix
Electron Transport Chain
3.
•
ATP is synthesized - Occurs in mito membrane
Section 9-2
Flowchart
Cellular Respiration
Glucose
(C6H1206)
+
Oxygen
(02)
Glycolysis
Krebs
Cycle
Electron
Transport
Chain
Carbon
Dioxide
(CO2)
+
Water
(H2O)
+
ATP
Where Does Cellular Respiration
Take Place?
It
actually
takes place in
two parts of
the cell:
Glycolysis occurs
in the Cytoplasm
Krebs Cycle &
ETC Take place in
the Mitochondria
Copyright Cmassengale
Glycolysis
 Definition:
The process in which one
molecule of glucose is broken in
half, producing two molecules of
pyruvic acid, a 3-carbon
compound.
Glycolysis
 Glyco
= glucose
Lysis = break down
 LOCATION: Occurs in the cytoplasm
 This stage occurs in BOTH aerobic and
anaerobic respiration
 Occurs
in ALL eukaryotic cells…
Glycolysis- ATP Production
 In
the pathways beginning, 2 ATP
molecules are used up.
 At the end of glycolysis, 4 ATP
molecules are formed.
 NET GAIN- 2 molecules!!!
Glycolysis- NADH Production
 Process
removes 4 high energy e- and
passes them to nicotinamide adenine
dinuclueotide (NAD+), which is an electron
carrier.
 NAD+ turns into NADH while transferring
electrons to other molecules.
Steps of Glycolysis
1.Two ATP molecules are used to energize a
glucose molecule.
2. Glucose is split into 2 3-carbon molecules.
Enzymes rearrange the molecules.
3. Electrons are transferred to NADP. The
carbon molecules are converted to pyruvate
which enters cellular respiration.
Glycolysis





Location= Cytoplasm
NO O2 required
Energy Yield net gain of 2 ATP at the
expense of 2 ATP
6-C glucose  TWO 3-C pyruvates
Free e- and H+ combine with organic ion
carriers called NAD+  NADH + H+
(nicotinamide dinucleotide)Used in ETC.
Hydrogen attached to water.
Glycolysis:
Get a sheet of paper to review the
process of glycolysis.
Video: Glycolysis
Glycolysis:
Figure 9–3 Glycolysis
Step 1
Glucose
2 Pyruvic acid
To the electron
transport chain
Glycolysis Reactants and Products
Reactants
 1 glucose
 Enzymes are needed
 2 ATP are needed to
start
Products
 2 Pyruvates (go to next
step)
 4 ATP (2 are gained)
 2 NADH (go to ETC)
Really 10 steps with 10 different enzymes
involved.
Anaerobic Respiration (without oxygen):
Fermentation
***fermentation does not make ATP for the cell,
it cycles the ATP for glycolysis***
(does not release energy in cell)
Two Main types:
1) Lactic Acid fermentation- converts pyruvic
acid and NADH to lactic acid and NAD+
-muscle cells
2) Alcoholic fermentation- converts pyruvic acid
and NADH to ethyl alcohol, CO2, NAD+
-yeast (air bubbles in bread)
Main Goals of Krebs Cycle
 Transfer
•
•
high energy electrons(NADH and
FADH2) to molecules that can carry them
to the electron transport chain.
Form some ATP molecules.
Takes place in mitochondria
Krebs Cycle-
Part A (Citric Acid Production)
 From
glycolysis, the 3carbon molecule (pyruvic
acid/pyruvate) enters the mitochondria
(innermost layer- Matrix)
 3carbon pyruvic acid is broken down into
2carbon (Acetyl-CoA) molecules.
 CO2 and NADH are produced

Hint: anytime the number of carbons are
reduced, CO2 and NADH are produced
 Acetyl-CoA
(2carbon) combines with 4 carbon
compounds forming a 6 carbon molecule
Citric acid.
Krebs Cycle
Part B (Energy Extraction)
 The
6carbon Citric Acid broken down into
5 carbon compound (releasing CO2 &
NADH)
 5 carbon compound broken down into 4
carbon compound (releasing CO2 &
NADH)
 In a series of 4carbon to 4carbon
reactions, ATP, CO2, NADH & FADH2 are
produced

Remember: NADH & FADH2 are electron
carriers that will take the electrons to the
ETC
Kreb Cycle
Krebs Cycle Reactants and Products
Reactants
 2 Acetyl CoA (pyruvic
acid)
 Remember
when you
form a bond energy is
released!! This is the
key!!
Products
2
ATP
 8 NADH (go to ETC)
 2 FADH2 (go to ETC)
 6 CO2 (given off as
waste)
Krebs Cycle
Electron Transport Chain
 Where
inner membrane of mitochondria
called cristea.
 Energy Yield Total of 32 ATP
 O2 combines with TWO H+ to form H2O
 Exhale - CO2, H2O comes from cellular
respiration
 Video:
ETC
Electron Transport Chain
Section 9-2
Electron Transport
Hydrogen Ion Movement
Channel
Mitochondrion
Intermembrane
Space
ATP synthase
Inner
Membrane
Matrix
ATP Production
Electron Transport - Step 3
1. Proteins inside the membrane of the mito.
Remove electrons from NADPh and FADH.
2. Electrons(hydrogen) are transported down
the chain of the membrane to be pumped
across.
3. ATP synthase(enzyme) puts a P on ADP to
make ATP(END GOAL!!).
4. Oxygen enters the cycle to pick up electrons
and hydrogen ions to make water that leaves
the cycle.
Electron Transport Chain



Electron carriers loaded with electrons and
protons from the Kreb’s cycle move to this
chain-like a series of steps (staircase).
As electrons drop down stairs, energy
released to form a total of 32 ATP – Final
Goal!!
Oxygen waits at bottom of staircase, picks up
electrons and protons and in doing so
becomes water
Energy Tally


36 ATP for aerobic vs. 2 ATP for anaerobic

Glycolysis
2 ATP

Kreb’s
2 ATP

Electron Transport
32 ATP
36 ATP
Anaerobic organisms can’t be too energetic
but are important for global recycling of
carbon
Section 9-2
Flowchart
Cellular Respiration
Glucose
(C6H1206)
+
Oxygen
(02)
Glycolysis
Krebs
Cycle
Electron
Transport
Chain
Carbon
Dioxide
(CO2)
+
Water
(H2O)
+
ATP