general overview of metabolism

1. Medical Biochemistry and Genetics (BC 115)
Overview of Metabolism
Chimuka Mwaanga (BSc, MSc, PhD)
0966-130052, chimuka83mwaanga@yahoo.com

2.  Continuous Assessment 40%
Written tests 20%
Quiz 5%
Assignment(s) 5%
Laboratory practical exercises 10%
 End of Year Examination 60%
Assessment Methods

3. 1. Ahmed, N and Smith, C (2011). Clinical Biochemistry
Fundamentals of Biomedical Science. Oxford University Press, Oxford. ISBN: 0199533938
2. Berg, J. M, Tymoczko, J. L, and Stryer, L (2011). Biochemistry (7th Edition). W.H. Freeman and Co, New
York. ISBN: 1429276355
3. Blackstock, J.C (1999). Biomedical Sciences Explained: Biochemistry. Butterworth-Heinemann, Oxford.
ISBN: 0 7506 3256 9
4. Marshall, W. J and Bangert, S. K (2008). Clinical Biochemistry: metabolic and clinical aspects. Churchill-
Livingstone- Elsevier, London. ISBN 978 0 443 10186 1
Prescribed Textbooks

4. 1. Varley, H, (2006). Practical Clinical Biochemistry, CBS Publishers and Distributors, London. ISBN:-10:
8123904274
2. Zilva, T.F, Pannall, R.P and Mayne, P.D (1988). Clinical Chemistry in Diagnosis and Treatment (5th
Edition). Lloyd-Luke Medical Books, London
3. Devlin, T.M (2011). Textbook of Biochemistry with Clinical Correlations (7th Edition). Wiley-Liss, New
York. ISBN: 0470281731
4. Lehninger, A.L, Nelson, D.L and Cox, M.M (2012). Principles of Biochemistry (6th Edition). Worth
Publishers, New York. ISBN: 1429234148
5. Matthews, C.K and van Holde, K.E (2012). Biochemistry (4th edition) Prentice-Hall, Harlow, Essex. ISBN:
0138004641
Recommended References

5. Two-way street connecting Biochemistry and Medicine
Nucleic acids
Genetic
diseases
Proteins
Sickle cell
anaemia
Biochemistry
Medicine
Lipids
Atherosclerosis
Carbohydrates
Diabetes
mellitus

6. 1. Metabolic diversity
2. Anabolic and catabolic processes
Overview of Metabolism

7. What is metabolism?
Metabolism is the entire process of synthesis or breakdown of compounds in the cell.
Metabolic pathways fall into three categories:
(1) Anabolic pathways are those involved in the synthesis of compounds and they are
endergonic.
(2) Catabolic pathways are involved in the breakdown of larger molecules, commonly
involving oxidative reactions; they are exergonic, producing reducing equivalents and,
mainly via the respiratory chain, ATP.
(3) Amphibolic pathways occur at the “crossroads” of metabolism, acting as links between
the anabolic and catabolic pathways, e.g., the citric acid cycle.

8. Normal Metabolism Vs Abnormal Metabolism
• A knowledge of normal metabolism is essential for an understanding of
abnormalities underlying disease.
• Normal metabolism includes adaptation to periods of starvation, exercise,
pregnancy, and lactation.
• Abnormal metabolism may result from nutritional deficiency, enzyme
deficiency, abnormal secretion of hormones, or the actions of drugs and
toxins.
• An important example of a metabolic disease is diabetes mellitus.

9. Outline of Catabolic Pathways

10. Overview of Carbohydrate Metabolism
Glycerol 3-phosphate
Glycogen
Glucose
Pyruvate
Glucose
phosphates
Ribose
phosphates
RNA
DNA
Glycolysis
Pentose phosphates
pathway
Glycerol 3-phosphate
2CO2

11. Overview of Lipid Metabolism
TCA cycle Ketone bodies
Ketogenesis
Steroidogenesis
Acetyl CoA
Fatty Acids
Triacylglycerol
(fat)

12. Overview of Amino Acid Metabolism

13. In addition to studying the whole organism, the location and integration of
metabolic pathways is revealed by studies at several levels of organization.
1. At the tissue and organ level, the nature of the substrates entering and
metabolites leaving tissues and organs is defined.
2. At the subcellular level, each cell organelle (e.g., the mitochondrion) or
compartment (e.g., the cytosol) has specific roles that form part of a
subcellular pattern of metabolic pathways.
Metabolic Pathways may be Studied at Different
Levels of Organization

14. Carbohydrate and Protein Metabolic Pathways at Tissue/Organ
Levels

15. Lipid Metabolic Organisation at Tissue/Organ Level

16. Metabolic Pathways at Subcellular Level
CYTOSOL
MITOCHONDRION

17. Regulation of Metabolic Reactions
Circled numbers indicate possible sites of
action of hormones.
1. Alteration of membrane permeability;
2. Conversion of an inactive to an active
enzyme, usually involving
phosphorylation/dephosphorylation reactions;
3. Alteration of the rate
of translation of mRNA at the ribosomal level;
4. Induction of new mRNA formation; and 5.
Repression of mRNA formation.