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Chapter 7
Metabolism: Transformations and
Interactions
Anabolic Processes (build up)
Examples:
ENERGY
glucose + glucose +......
glycogen
ENERGY
amino acid + amino acid +......
protein
Catabolic Processes (break down)
Examples:
ENERGY
glycogen
glucose + glucose +......
ENERGY
protein
amino acid + amino acid +......
ATP (Adenosine Triphosphate)
NH2
N
N
O
N
N
OH
Adenosine
O
O
O P O P O P O
O
O
OH
O
O
3 Phosphates
Transfer of Energy
Utilizing ATP
How Efficient is this Process?
 From the food we ingest, we only capture
about 50% of the energy in the bonds in the
form of ATP.
 When we utilize the ATP to “fuel” other
anabolic processes, we only utilize about 50%
of the ATP’s energy.
Where does the “LOST ENERGY” go?
Overview of
energy
metabolism.
Carbs
Lipids
Protein
(amino
acids)
TCA
Cycle
Energy
Production
Lets Start with Carbs:
Glycolysis (anaerobic)
Release
of Small
Amount
of Energy
A Simplified Eukaryote Cell
Cell Membrane
Cytoplasm
Nuclear
Membrane
Chromosomes
Mitochondria
Endoplasmic Reticulum
(ribosomes)
Pyruvate-to-Acetyl CoA (aerobic)
Cofactor
Irreversible Step
The Breakdown
of Acetyl CoA
To
Energy
(aerobic)
TCA
Cycle
Electron Transport
Chain
SUMMARY:
Glucose-to-energy
pathway
Fatty Acid Oxidation
Fats-toenergy
pathway
Transamination:
Making Nonessential Amino Acid
Deamination to give Keto Acids
Amino Acids-to-energy
pathway
What happens to the NH3?
Urea synthesis
Urea excretion
Amino Acids
bloodstream
Liver
bloodstream
Kidney
Electron Transport Chain
Why does Fat Produce more Energy
than Glucose?
Mol. Weight = 256.42
Acetyl CoA produced = 8
ATP’s produced = 129
ATP’s per gram = 0.50
Mol. Weight = 180.16
Acetyl CoA produced = 2
ATP’s produced = 38
ATP’s per gram = 0.21
During Feasting - High Dietary Intake
Carbohydrates
Fat
Proteins
Glucose
Glycogen Stores
Fatty Acids
Body Fat Stores
Amino Acids
Body Proteins
During Fasting -
Low Dietary Intact
Glycogen Stores
Glucose
Body Fat Stores
Fatty Acids
Energy for Brain,
Nervous System and
Blood Cells
Energy for other Cells
If Fasting Continues -
Body Protein
Still Low Dietary Intact
Amino Acids
Glucose
Energy for Brain,
Nervous System and
Blood Cells
Ketone
Bodies
Body Fat Stores
Fatty Acids
Energy for other Cells
Ketosis: Ketone Body formation
H O
H O
H C C CoA
+
H C C CoA
H
H
2 CoA
H O H O
H C C C C OH
H
Acetoacetate
H
CO2
H O H
H C C C H
H
H
Acetone
Alcohol metabolism
NAD+ NADH + H+
H H
H C C OH
H H
Ethanol
H O
H C C H
H
Acetaldehyde
NAD+
NADH + H+
H O
H C C CoA
H
Acetyl CoA
H O
H C C OH
H
Acetic Acid
Alternate route
for Acetyl CoA
Fat
NADH
blocks entry