Download Aerobic Cellular Respiration PPT File

What is energy coupling AND
what does that have to do with ATP?
Think of energy as money….
ATP picks up the energy released from an exergonic reaction, and drops energy
off to go into an endergonic reaction. ATP is the middle man.
CELLULAR RESPIRATION
YOU WOULD BE DEAD
WITHOUT THIS
PROCESS TOO!
Cellular respiration is how we derive (harvest) energy from the food we eat.
eh hem….what do you notice?
•Reactants: C₆H₁₂O₆ + 6 O₂
•Products: 6 CO₂ + 6 H₂O + Energy
~ 38 ATP
&
Heat
Aerobic Respiration has three stages…
1.
2.
Also known as the ‘Citric Acid Cycle’
3.
GOOD NEWS!!!
• Memorization of the
steps of Glycolysis and
the Krebs cycle,
structures of molecules,
and names of enzymes
involved (except ATP
Synthase) are beyond the
scope of the course and
the AP EXAM
Besides glucose, other energyfilled molecules
(other carbs, proteins, and lipids)
can also be broken down for ATP
during cellular respiration.
Different types of molecules have
different entry points into this
process.
Varied diet can be consumed
without a loss of viable energy.
FIRST STAGE:
GLYCOLYSIS
Think about the break-down of this word.
The breaking down of sugar
‘related to’
To Break
(glucose).
SUGAR
What goes in to the reaction:
1 Glucose (C₆H₁₂O₆) and 2 ATPs (used to break the glucose)
Glycolysis takes
place outside of
the
mitochondria in
the cytoplasm.
FIRST STAGE:
GLYCOLYSIS
The breaking down of sugar
(glucose).
What is created:
2 Pyruvate (3-carbon molecules), 2 Waters, 2 NADH
(electron carriers), 4 ATPs (used to break the glucose)
FIRST STAGE:
GLYCOLYSIS
The breaking down of sugar
(glucose).
FOR A NET OF:
Begins
With..
Glycolysis basically
rearranges the glucose
molecule and breaks it
in half to make
2 Pyruvate
Ends
With..
,
,
2 NADH
Energy Input Steps
Energy Releasing Steps
Now Unstable
Energy Releasing Steps, cont.
Now Unstable
SECOND STAGE:
KREBS CYCLE
Also called ‘Citric Acid Cycle’
Inside the INNER
MEMBRANE OF
THE
MITOCHONDRIA
SECOND STAGE:
KREBS CYCLE
Also called ‘Citric Acid Cycle’
What goes in to the cycle:
2
What’s created:
The Krebs Cycle is a series of
reactions that take place in the
Mitochondria that synthesize
2 ATP and many energy-filled
electron transport molecules.
Carbon Dioxide is a waste product
ATP
Krebs Tally
6- CO2
8- NADH
2- ATP
2- FADH2
1. The 2 Pyruvates enter (3 carbon sugars)
2.
ATP
One carbon from each breaks off, attaches to an O₂,
and is released as a waste (2 CO₂), 2 NAD swoop in and
steal some energized electrons- creating 2 NADHs
3. What’s left is two 2-carbon molecules called Acetyl CoA
ATP
1.
Each Acetyl CoA combines with a 4 carbon
oxaloacetate, creating citric acid
2.
Citric acid is taken through many reactions that create
2 ATPs , 6 more NADHs, and 2 FADH₂
3.
4 more CO₂ molecules are given off and in the end
there are 2 oxaloacetate’s ready to do it all over again.
Much like NADPH in photosynthesis, NADH and FADH₂ are simply carrier
molecules of energized electrons and hydrogen ions. They take the energy
from one place and drop it off at another.
ATP accounting so far…
• Glycolysis  2 ATP
• Kreb’s cycle  2 ATP
• Life takes a lot of energy to run, need to extract more energy than 4 ATP!
I need a lot
more ATP!
A working muscle recycles over
10 million ATPs per second
THIRD STAGE:
Electron Transport Chain
Phosphorylation
2
THIRD STAGE:
Electron Transport Chain
Instead of light energy like in Photosynthesis, this time excited electrons are being dropped off at
the ETC by all of the electron carriers from Glycolysis and Krebs (in all 10 NADH and 2 FADH₂)
Same as before, as the excited electrons travel from protein to protein their energy is used to
pump H⁺ into the space between the inner and outer mitochondrial membranes.
The FINAL ELECTRON ACCEPTOR IN CELLULAR RESPIRATION THAT PICKS UP THE EXCITED
ELECTRONS IS A SINGLE OXYGEN ATOM.
It also picks up two Hydrogen ions and becomes a water molecule!
All the H+
H+
H+
H+
• Concentration is too high on one side of the membrane
H+
H+
H+
H+
• The protons flow through ATP synthase - enzyme
• Uses ‘proton motive force’ energy to Synthesizes ATP
ADP + Pi  ATP
ADP + Pi
ATP
H+
H+
What can slow the rate of CR?
• Decrease in breathing rate, pulse rate, or food in-take
• Decrease in temperature