Gene expression
Gene sequences occupy only about 2% of the human genome. Following the successful genome project that enabled the sequence of bases in the human genome (3 billion) to be elucidated,…
DNA and RNA
Deoxyribonucleic acid (DNA) DNA is the hereditary material in prokaryotic and eukaryotic cells. It consists of four nitrogenous bases, adenine (A), guanine (G), cytosine (C) and thymine (T), attached to…
Principles of molecular genetics
Prior to the development of molecular genetic techniques our understanding of genetic disease and potential treatments was based on the analysis of pedigrees and studying abnormal proteins. The knowledge gained…
Amino acid metabolism
Amino acid synthesis Of the 20 amino acids needed for protein synthesis, humans are only able to make 11. These are termed the non-essential amino acids and are made by…
Glucose metabolism
Approximately 55% of the energy needs of the average human are met by the metabolism of carbohydrates, of which the major component is glucose. The glucose concentration in the blood…
Fat metabolism
Lipids (fats and oils) are a high-energy source yielding twice the energy per gram of protein and carbohydrate. Around 30% of calorific intake by humans is currently recommended, as an…
Central metabolic pathways
Catabolism of lipids, carbohydrates and the carbon skeletons of some amino acids converge on acetylCoA. AcetylCoA is a precursor for ketone bodies (acetoacetate and β-hydroxybutyrate) and for the biosynthesis of…
General principles of cellular metabolism
Metabolism can be described as the sum of the chemical reactions in an organism that produce and maintain its molecular structure, and the chemical reactions that make energy available for…
Basic mechanisms of drug action
Drugs interact with their specific target, which may be coupled to a second messenger and/or effector system, leading to a cellular response. Pharmacological targets Receptors Receptors are proteins that are…
Carbohydrate biochemistry
Carbohydrates (CHOs) are probably the most abundant organic molecules in living organisms and serve a variety of roles. Carbohydrates provide about 55% of dietary calories for a healthy human, so…
