Transcript Metabolism overview - College of the Holy Cross

Metabolism -- ~P Regulation
The Measurement of Metabolism
We will not directly follow these processes any more than a
chemist does who measures the heat evolved or taken in by a
process.
Methods all involve assumptions -- in a way it is like measuring
the economy and no one measure is perfect.
Phosphagen Cycle -- Phosphagen
Buffer During High Demand
This process is controlled by the amount of enzyme present (CK)
and thermodynamically (amts. of reactants/products)
Replenishment of Phosphagen
The Krebs Cycle
Take Home:
•Occurs in the
mitochondrial matrix
•Rate is very
dependent on the
ratio of oxidized to
reduced coenzyme
•Feed ins -- 2 C frags..
from carbohydrate
and fat metabolism;
•Amino acid frags in
other places
Energy Schematic of the
ETS
Take Home
•In inner
membrane
•Will maintain a
favorable steadystate ratio of
oxidized to reduced
coenzyme if
sufficient O2 is
present to accept
each electron
produced in the
Krebs and other
reactions.
Mitochondrial Overall Energy
Schematic
Glycolysis
Energy
Schematic
Aerobic
Glycolysis
Overview
Energetics of Aerobic Glycolysis
The overall reaction (path does not matter):
A distinct stoichiometry exists between all members of this
process.
This means that if we know carbohydrate is the fuel, then if we
measure the change in one component of this reaction, we know
the changes in all others.
How About Lipid?
Once again, if we know that lipid (palmitic acid) is the
fuel, we can measure one factor in the reaction and find
all the others.
How do we know the fuel being used?
You cannot tell simply from what the animal eats.
There is a certain ratio of CO2 production to O2 consumption exists
for different fuels. For carbs:
Ratio is 1:1
The Ratio is Different In Palmitic Acid
16/23 = 0.7
The Respiratory Quotient (RQ)
·
RQ =
V CO 2
·
V O2
·
=
M CO 2
·
M O2
How the Table Values For Energy Equivalence
Were Obtained – An example