1. UNIT 12 CS 40-42 BASIC CONCEPTS OF METABOLISM
Prepared by: Mr. Norman P. Gutierrez, RN, MAN
26TH November 2012

2. Learning Objectives Define anabolism, catabolism and metabolism.
Explain electoral transport chain.
Explain source of energy extracted from metabolic fuel.
Prepared by: Mr. Norman
9/16/2018

3. Learning Objectives Explain the source of energy extracted from food.
Explain the biomedical importance of metabolism.
Describe carbohydrate metabolism.
Prepared by: Mr. Norman
9/16/2018

4. Learning Objectives Describe lipid metabolism.
Describe amino acid metabolism.
Explain the interrelationship in the metabolism of proteins, lipids and carbohydrates.
Prepared by: Mr. Norman
9/16/2018

5. DEFINITION OF TERMS CATABOLIC ANABOLIC
Break down complex molecules such as proteins, polysaccharides and lipids to a few simple molecules like CO2, NH3 and H20
ANABOLIC
Forms complex end products from simple precursor
Smaller molecules are used to synthesize big and complex molecules
Prepared by: Mr. Norman
9/16/2018

6. DEFINITION OF TERMS METABOLSIM
Is the total chemical changes taking place in the cell.
Prepared by: Mr. Norman
9/16/2018

7. Source of Energy Comes from high energy compounds
Key compound: Adenosine triphosphate (ATP), hydrolysis of ATP to ADP (adenosine diphosphate) and inorganic phosphate (7,600 cal/mol)
ATP supply in the body is limited
Body changes ADP back to ATP by adding high energy phosphate group to ADP (phosphorylation)
Prepared by: Mr. Norman
9/16/2018

8. ELECTRON TRANSPORT CHAIN
Series of Reactions
Passes electron to oxygen
Glucose & Fatty acids Are metabolized by OXIDATION
CO2 + H2O
NAD
FAD
NADH and FADH
Prepared by: Mr. Norman
9/16/2018

9. ELECTRON TRANSPORT CHAIN
Electron passed ETC
Lose much of free energy
Captured and stored by ATP production (ADP + Pi)
Oxidative phosphorylation
Limited to Mitochondrion
Final common pathway by which electrons
derived form different fuels of the body flow to oxygen!

10. EXTRACTION OF ENERGY FROM METABOLIC FUELS
From food via oxidation
(CO2+H2O)
1st stage:
Metabolic fuels (CHO, COOH & CHON) are hydrolysed to their monomeric building blocks
2nd stage:
Building blocks are degraded to various pathways to a common metabolic intermediate, ACETYL CoA
3rd stage:
Citric acid oxidizes acetyl CoA to CO2 ---C-C & C-H =
NADH+FADH2
Final Stage
Extraction from oxidative phosphorylation
Electron pairs of NADH & FADH2 via ETC – used to synthesize ATP
Prepared by: Mr. Norman
9/16/2018

11. EXTRACTION OF ENERGY FROM METABOLIC FUELS
From food via oxidation
(CO2+H2O)
1st stage:
Metabolic fuels (CHO, COOH & CHON) are hydrolysed to their monomeric building blocks
2nd stage:
Building blocks are degraded to various pathways to a common metabolic intermediate, ACETYL CoA
3rd stage:
Citric acid oxidizes acetyl CoA to CO2 ---C-C & C-H =
NADH+FADH2
Final Stage
Extraction from oxidative phosphorylation
Electron pairs of NADH & FADH2 via ETC – used to synthesize ATP
Prepared by: Mr. Norman
9/16/2018

12. EXTRACTION OF ENERGY FROM METABOLIC FUELS
Carbohydrates
Protein
Lipids
Stage I
Hydrolysis of metabolic
fuels to their building blocks
Glucose
Amino Acids
Fatty Acids
Stage II
Conversion of building
Blocks to acetyl CoA
Acetyl CoA
CITRIC
ACID CYCLE
Stage III
Oxidation of acetyl CoA
Stage IV
Oxidative Phosphorylation
3NADH & FADH2
2CO2 O
e ETC e-
H2O
Prepared by: Mr. Norman
ADP + Pi
ATP
9/16/2018

13. BIOMEDICAL IMPORTANCE OF METABOLISM
Provides a sound understanding of many diseases
Variations and adaptations due to starvation, exercise, pregnancy and lactation are included in normal metabolism
Abnormal metabolism results from nutritional deficiency, enzyme deficiency and excessive secretion of hormones
Diabetes mellitus is an example of disease caused by abnormal metabolism
Prepared by: Mr. Norman
9/16/2018

14. CARBOHYDRATE METABOLISM
Pyruvate and lactate are formed in the mammalian cells as a result of oxidation of glucose by glycolysis.
In the absence of oxygen , glycolysis occurs in the cytoplasm of the cells producing lactate only.
Under aerobic conditions pyruvate is metabolized to acetyl CoA which enters citric acid cycle for complete oxidation to CO2 and H2O.
Prepared by: Mr. Norman
9/16/2018

15. CARBOHYDRATE METABOLISM
Glucose also takes part in other metabolic processes:
It is converted to glycogen for storage particularly in liver and skeletal muscles.
The HMP shunt or pentose phosphate pathway arriving from intermediates of glycolysis is a source of reducing equivalents (2H) for biosynthesis of fatty acids, cholesterol, etc. and is a source of ribose which is required for nucleic acids formation.
Prepared by: Mr. Norman
9/16/2018

16. CARBOHYDRATE METABOLISM
Glucose also takes part in other metabolic processes:
Triose phosphate of glycolysis is a source of glycerol of fat.
Pyruvate and intermediates of TCA cycle form amino acids and cholesterol, the precursor of all steroid hormones in the body.
Prepared by: Mr. Norman
9/16/2018

17. LIPID METABOLISM
The long chain fatty acids are synthesized from acetyl CoA derived from CHO or from dietary lipids.
In the tissues, fatty acids are oxidized to acetyl CoA or esterified to acyl glycerol to form fat which is the main calorie reserve of the body.
Prepared by: Mr. Norman
9/16/2018

18. LIPID METABOLISM
Acyl CoA formed by the β oxidation has the following significant roles in the body:
It liberates CO2 and H2O and also yields high energy.
It is a source of cholesterol biosynthesis.
In liver it forms ketone bodies which are alternate water soluble tissue fuels. (this fuels become important sources of energy)
Prepared by: Mr. Norman
9/16/2018

19. AMINO ACID METABOLISM Amino acids are required for protein synthesis.
The essential amino acids must be supplied in diet since they are not synthesized by the tissues.
Diet can supplement non-essential amino acids which are also formed from the intermediates of citric acid cycle by transamination.
Prepared by: Mr. Norman
9/16/2018

20. AMINO ACID METABOLISM
Excess amino nitrogen as a result of deamination give the following products:
CO2 and H2O via citric acid cycle.
Glucose by gluconeogenesis.
Ketone bodies.
Amino acids are precursors of many other important compounds like purines, pyrimidines and hormones such as epinephrine and thyroxine.
Prepared by: Mr. Norman
9/16/2018

21. INTER-RELATIONSHIP IN THE METABOLISM OF PROTEINS, LIPIDS & CARBOHYDRATES
GLUCOSE Glycerol thru triosephosphate and acetyl CoA thru pyruvate.
ACETYL CoA helps the formation of fatty acids with malonyl CoA.
GLYCEROL and FATTY ACIDS combine to form TRIACYLGLYCEROL (neutral fat).
Prepared by: Mr. Norman
9/16/2018

22. INTER-RELATIONSHIP IN THE METABOLISM OF PROTEINS, LIPIDS & CARBOHYDRATES
KETOACIDS in TCA cycle are converted into amino acids by transamination.
FAT is oxidized to form acetyl CoA which enters the citric acid cycle.
MALATE of citric acid cycle pass thru mitochondrial membrane into CYTOSOL converted to glucose by gluconeogenesis.
Prepared by: Mr. Norman
9/16/2018

23. INTER-RELATIONSHIP IN THE METABOLISM OF PROTEINS, LIPIDS & CARBOHYDRATES
FATTY ACIDS with odd number of carbon atoms also enters citric acid cycle PROPIONATE
PROTEIN is hydrolyzed to AMINO ACIDS.
Prepared by: Mr. Norman
9/16/2018

24. Any Question???
Thank You!
Prepared by: Mr. Norman
9/16/2018