Metabolism- Biochemistry

1. METABOLISM

2. Metabolism: FON 241; L. Zienkewicz
Metabolism:
•Metabolism: refers to the entire
network of chemical processes
involved in maintaining life.
•Energy metabolism: the ways that the
body obtains and spends energy from
food.

3. Metabolism: FON 241; L. Zienkewicz
•Anabolism: The building of compounds from
small molecules into larger ones. Energy is
used for this process to take place.
•Catabolism: The breakdown of molecules
into smaller units. Energy is released in this
process.
–Ex: Glucose catabolism results in the release of
CO
2
and H
2
O

4. Metabolism: FON 241; L. Zienkewicz
ATP (Adenosine Triphosphate):
•The main energy source of cells.
•Used for muscular contractions,
enzyme activity, etc.
•Catabolism results in the production of
many ATP molecules: energy.
•Used by the body when energy is
needed.
•Hydrolysis breaks the bonds in ATP,
thus releasing energy.

5. Metabolism: FON 241; L. Zienkewicz
Metabolic Efficiency:
•Food energy is converted to ATP with
approximately 50% efficiency.
•The other 50% is released as heat.

6. Metabolism: FON 241; L. Zienkewicz
The Cell:
Q: Approximately how many cells does
the human body contain?
A: 1x10
14
cells or
100,000,000,000,000. (100 trillion cells)

7. Metabolism: FON 241; L. Zienkewicz
The Cell:
•The site for metabolic activity.
•Liver cells are the most metabolically
active.

8. Metabolism: FON 241; L. Zienkewicz
How is energy produced?
Three stages:
1. Proteins, Carbohydrates and Fats are
broken down during digestion and
absorption into smaller units: AAs,
monosaccharides and fatty acids.
2. These smaller compounds are further
broken down into 2-carbon
compounds.
3. Compounds are degraded into CO
2
and H
2
0.

9. Metabolism: FON 241; L. Zienkewicz
Helpers in reactions:
•Enzymes: proteins that facilitate
chemical reactions without being
changed in the process; protein
catalysts.
•Coenzymes: assist enzymes in their
activities.

10. Metabolism: FON 241; L. Zienkewicz
Breakdown of nutrients for energy:
1.Glucose breakdown
2.Glycerol and Fatty Acid breakdown
3.Amino Acid breakdown
Common Pathway
Energy
Fats
Carbohydrates
Protein

11. Metabolism: FON 241; L. Zienkewicz
1. Glucose breakdown
Glycolysis: A reaction in which glucose is
degraded to pyruvate; net profit: 2 ATP.
An anaerobic pathway.
Glucose
Pyruvate
Lactic Acid Acetyl CoA
Oxygen available
2 ATP
Less oxygen available

12. Metabolism: FON 241; L. Zienkewicz
The path from Pyruvate to Acetyl CoA is NOT reversible.

13. Metabolism: FON 241; L. Zienkewicz

14. Metabolism: FON 241; L. Zienkewicz
2. Glycerol and Fatty Acid breakdown
Triglycerides are broken into:
Glycerol and Fatty Acids (lipolysis).
Glucose
Glycerol
Pyruvate
Fatty acids
Acetyl CoA

15. Metabolism: FON 241; L. Zienkewicz
3. Amino Acid breakdown
Glucose
Amino Acids
Pyruvate
Amino Acids
Acetyl CoA
Amino Acids
TCA Cycle

16. Metabolism: FON 241; L. Zienkewicz
3. Amino Acid breakdown (cont.)
•Deamination: AA Keto acid and Ammonia
•Transamination
•Ammonia Urea in the Liver
•Urea excreted via the kidneys
•Water needed for urea excretion

17. Metabolism: FON 241; L. Zienkewicz
The TCA Cycle:
•Functions to convert Acetyl CoA to CO
2

and to produce energy.
•Oxaloacetate combines with Acetyl
CoA to begin the cycle.
•The result: produces potential ATP
(energy).

18. Metabolism: FON 241; L. Zienkewicz
The Electron Transport Chain:
•The primary site for ATP (energy) synthesis.
•Uses Oxygen to convert products of the TCA
cycle into energy.

19. Metabolism: FON 241; L. Zienkewicz
Why is fat higher in energy?
•Fat’s carbon-hydrogen bonds can be easily oxidized, yielding
energy (ATP).
•1 glucose molecule yields 38 ATP when oxidized.
•1 fatty-acid (16-C) will yield 129 ATP when oxidized.