Download Aerobic Respiration

Aerobic Respiration
Remember…
• Cellular respiration is
the breakdown of
glucose into energy
• So far we have learned
about glycolysis
• Glycolysis is the first of
many steps in cellular
respiration
• Glycolysis happens in
the cytoplasm
Remember…
• Glycolysis is the
formation of 2 ATP, 2
NADH and 2 pyruvate
from the energy that is
given off by the splitting
of glucose
• It is a complex process
that involves energy
investment and energy
payoff
Before The Next Step
• After glycolysis and
before our next step
some very important
things happen
• We have to first
determine the type of
respiration that will
follow
• If there are mitochondria
and oxygen present most
cells will perform aerobic
respiration
Before The Next Step
• Before aerobic
respiration happens a
series of reactions
happens to pyruvate
• These reactions happen
in the mitochondria
• This is because the
mitochondria is the
sight of aerobic
respiration
Before The Next Step
• Pyruvate is acted on by
a large multiple enzyme
complex that performs
three key reactions in a
short time
1. Pyruvate loses a
carboxyl group (COO-)
which is transported out
of the cell as CO2
Before The Next Step
2. The remaining 2 carbon
compound is oxidized
(loses electrons) to create
a molecule of NADH from
NAD+
3. A compound called
coenzyme A joins in with
the two carbon compound
to form acetyl CoA
Intro Citric Acid Cycle
• The next step in the
process is the Citric
Acid Cycle
• This cycle can also be
called the “Krebs” cycle
in honor of Hans Krebs
• Hans Krebs was a
German/British
researcher that
discovered most of the
steps to the cycle
Intro Citric Acid Cycle
• The purpose of the Krebs
Cycle is to create ATP, 3
NADH and FADH2
(another electron carrier)
• This will create a large
amount of electrons that
can be carried to the next
step in aerobic respiration
• A byproduct of this series
of reactions is CO2
• This all happens in the
mitochondrial Matrix
Citric Acid Cycle
1.Acetyl CoA enters the cycle and
gets the whole cycle started by
leaving. The remaining 2 carbon
compound will combine with a 4
carbon compound called
oxaloacetate. The product of this
reaction is the 6 carbon compound
Citrate (does that look familiar?)
2.Citrate is oxidized and NAD+ is
reduced. A carboxyl group (COO-)
leaves as CO2. The resulting
compound is a 5 carbon Alphaketoglutrate.
Citric Acid Cycle
Citric Acid Cycle
3. The Alpha-ketoglutrate loses a carboxyl
group (COO-) and once again NAD+ is
reduced to NADH. Through substrate level
phosphorylation a molecule of ADP + P is
made into ATP. We are left with a 4 carbon
compound called Succinate.
4. The succinate is oxidized and the
electrons go to a molecule called FAD. This
creates FADH2. The resulting compound is a
4 carbon Malate.
5. Finally the Malate is converted to our
original 4 carbon compound Oxaloacetate
when it loses two electrons and creates
another molecule of NADH
Citric Acid Cycle
Citric Acid Helper!
So What Just Happened?
• You might have just felt
like you were punched
in the gut…
• That’s ok
• Here is something to
make you feel better
• https://www.youtube.c
om/watch?v=Bo8Q88b
AXyQ
So What Just Happened?
• Ok… back to business
• The Krebs Cycle produced
some very valuable things
• 2 ATP
• 6 Molecules of NADH
(each carrying 2
electrons)
• 2 Molecules of FADH2
(carrying 2 electrons)
• 4 Molecules of CO2
The Totals
These are the totals for all the steps of aerobic respiration
so far…
Glycolysis
Pre Citric Acid
2 Net ATP
2 NADH
Citric Acid
2 ATP
2 NADH
6 NADH
2 FADH2
2 CO2
4 CO2
What’s Next?
• So far we have
produced 4 ATP, 8
NADH and 2 FADH2
• This is not a lot of
energy
• Considering the process
of a cell membrane
pump takes one ATP, we
would quickly run out
of energy for the cell
What’s Next?
• The next step is going to
convert electrons into a
huge energy payoff
• The process of oxidative
phosphorylation is where
stored electrons are used
to build an H+
concentration and power
ATP Synthase
Oxidative Phosphorylation
• The process of OP starts
in the inner membrane
• The electron transport
chain will be
responsible for using
electrons to pump H+
ions out of the matrix
• This process builds a
concentration gradient
outside of the
mitochondrial maxtix
Oxidative Phosphorylation
• Moving the electrons
from place to place are
protein complexes and
mobile electron carriers
• These complexes pump
the H+ ions creating the
gradient
• This will be used later to
create ATP
Oxidative Phosphorylation
• Once the electrons go
through the electron
transport chain, they
must end up somewhere
• They cannot just hang out
in the matrix
• Oxygen accepts the
electrons and two spare
H+ ions to create H20
• This means the oxygen
you breathe is the final
electron acceptor
Oxidative Phosphorylation
• Once there is a proper
concentration gradient,
the H+ ions diffuse back
into the matrix through
ATP Synthase
• This enzyme will use the
H+ ions to create ATP
• This process is called
chemiosmosis
I Care… Why?
• Oxidative
phosphorylation creates
the bulk of the energy
that you and I use
• It creates roughly 28
molecules of ATP per
glucose
• That is over 7 times the
amount produced by
glycolysis and the citric
acid cycle
Glycolysis
Krebs Cycle
Oxidative
Phosphorylati
on
I Care… Why?
• This means that cells
that are able to perform
aerobic cellular
respiration have a huge
advantage when it
comes to total ATP
energy
• They create more
energy per molecule of
glucose
The Totals
These are the totals for all the steps of aerobic respiration
so far…
Glycolysis
Pre Citric Acid
2 Net ATP
2 NADH
2 NADH
2 CO2
Citric Acid
Oxidative
Phosphorylation
Totals
2 ATP
28 ATP
32 ATP
6 NADH
USES NADH
2 FADH2
USES FADH2
4 CO2
6 CO2
6 H20
6 H2O