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Respiration
Equation:
Oxidation / Reduction
• What is oxidation?
• What is reduction?
Key Idea: When something is reduced it gains electrons and protons. These electrons
and protons have usually come from another chemical, so that chemical has been
oxidised. Therefore a REDOX reaction has taken place. This is also true if
something is oxidised it has lost electrons and protons. These have usually been
given to another chemical, sothat chemical has been reduced. Therefore this is
also a REDOX reaction.
Coenzymes – NAD+ and FAD
Has this been oxidised or reduced?
NAD+
FAD
+ 2e- + 2H+
+ 2e- + 2H+
NADH +
FADH2
H+
Structure of NAD and FAD
What
biochemical
group do they
belong to?
Evidence?
Structure of ATP
Nucleic acid
Components:
Synthesized
from?
Enzyme used?
Key Ideas – Why turn
glucose into ATP?
Glucose is already a form of potential
chemical energy, why turn it into ATP?
• Lots of little packets of energy (ATP)
can be made and used for lots of little
jobs in the cell. A job seldom requires
all the energy contained in one molecule
of glucose. (therefore efficient, not
wasteful!!)
• ATP will release energy quickly, glucose
will not, therefore it is an instant
source of energy for the cell
ATP the Universal
Energy Currency
Why universal?
Why currency?
Enables a cell to do work
3 examples:
Energy can be released quickly, only one
bond needs to be broken.
Enzyme used:
Bond broken:
Energy per mole 30.6KJ
Other features, soluble and easily
transported across membranes
Key Ideas - Making ATP
• To make ATP a phosphate group (Pi) has to
be added to ADP, this reaction is called
phosphorylation
ATP + Pi
ATP
The energy to add the Pi group can come in
three different ways:
1.Substrate level phosphorylation – use the
energy released from chemical reactions
2.Oxidative phosphorylation – use the
energy from high energy electrons
produced during oxidation reactions
3.Photophosphorylation – use the energy
from high energy electrons produced using
light energy
Substrate Level Phosphorylation
In respiration it is produced in this way
during glycolysis and the Krebs cycle
Triose
phosphate
to Pyruvate
– 4 ATP
produced
5C to 4C
compound
– 1 ATP
produced
each turn
Key Ideas - Chemiosmosis
• The energy from high energy electrons can
be used to produce a proton gradient
• A proton gradient can be used to produce
ATP, this called chemiosmosis
• As protons flow down the gradient, energy
is released, this energy is used to add a
Pi group to ADP
• Chemiosmosis is used to produce ATP in
respiration and photosynthesis
Key Enzymes
• Dehydrogenases
Involved in what type of reactions?
Catalyze the removal of?
• Decarboxylases
Involved in what type of reactions?
Catalyze the removal of?
Glycolysis
• What does it mean?
• Where are ATP needed?
• Where are ATP
produced?
• Where does it take
place?
• What are the net
products?
• Where can glycerol
enter?
After Glycolysis……
If no oxygen is available
• What happens to the
pyruvate?
• Why?
• Useful products produced?
After glycolysis….
If oxygen is available….
•What is this reaction
called?
•Where does it take place?
•Why is it described as an
oxidative
decarboxylation?
• Where can fatty acids
enter?
After the Link reaction….
• What is this series
of reactions
called?
• Where does it take
place?
• What useful
products
are produced per
glucose molecule?
Mitochondrial Structure
The Electron Transport Chain
The Electron Transport Chain
• Why is it called
this?
• Where do the electron
come from?
• What do they release
as they are passed
along?
• What is this used
for?
• pH /chemiosmosis /
Number of ATP molecules produced
• NAD leads to the production of 3 ATP
molecules
• FAD leads to the production of 2ATP
molecules
Why? – Carrier systems are different – NAD
linked to 3 pumps and FAD 2 pumps
Stage of Respiration
Glycolysis
Link Reaction
Krebs Cycle
Number of
red NAD
produced
Number of red Number of ATP
FAD produced produced
Summary of aerobic respiration?