Biochemistry - Comprehensive Guide

1. Structure and Function of Biomolecules

Biomolecules are organic molecules essential for life, including proteins, carbohydrates, lipids, and nucleic acids. Each has a unique structure and function:

• Proteins: Amino acids, peptide bonds, primary/secondary/tertiary/quaternary structures, folding, denaturation, and enzymes.
• Carbohydrates: Monosaccharides, disaccharides, polysaccharides, glycoproteins, and proteoglycans.
• Lipids: Fatty acids, triglycerides, phospholipids, steroids, and biological membranes.
• Nucleic Acids: DNA and RNA structure, nucleotides, nucleosides, and base pairing.

2. Metabolism

Metabolism involves the chemical reactions that sustain life, including:

• Carbohydrate Metabolism: Glycolysis, gluconeogenesis, citric acid cycle, and pentose phosphate pathway.
• Lipid Metabolism: Fatty acid oxidation (beta-oxidation), ketogenesis, and lipid biosynthesis.
• Protein and Amino Acid Metabolism: Transamination, deamination, urea cycle, and biosynthesis of non-essential amino acids.
• Nucleotide Metabolism: Purine and pyrimidine biosynthesis and degradation.
• Bioenergetics: ATP, electron transport chain, oxidative phosphorylation, and chemiosmotic theory.

3. Molecular Biology

Molecular biology focuses on the molecular basis of biological activity:

• DNA Replication, Repair, and Recombination: DNA polymerase, helicase, ligase, and repair mechanisms.
• Transcription and Translation: RNA polymerase, ribosomes, tRNA, mRNA, and the genetic code.
• Gene Regulation: Operons (lac operon, trp operon), epigenetics, and chromatin remodeling.
• Recombinant DNA Technology: Cloning, PCR, CRISPR-Cas9, and gene editing applications.

4. Enzymology

Enzymes are biological catalysts with specific functions:

• Enzyme kinetics (Michaelis-Menten equation, Lineweaver-Burk plot).
• Enzyme inhibition (competitive, non-competitive, uncompetitive).
• Allosteric regulation and covalent modification.
• Coenzymes and cofactors.

5. Signal Transduction

Signal transduction involves communication within and between cells:

• Hormones and receptors.
• Second messengers (cAMP, IP3, Ca2+).
• Signal transduction pathways (GPCRs, RTKs, JAK-STAT).
• Apoptosis and cell signaling.

6. Biochemical Techniques

Techniques used to study biomolecules include:

• Chromatography (HPLC, GC, TLC).
• Electrophoresis (SDS-PAGE, agarose gel).
• Spectroscopy (UV-Vis, fluorescence, NMR).
• Mass spectrometry and X-ray crystallography.
• Enzyme-linked immunosorbent assay (ELISA).

7. Clinical Biochemistry

Clinical biochemistry applies biochemical principles to medicine:

• Biomarkers for diseases (e.g., enzymes in myocardial infarction).
• Metabolic disorders (diabetes, phenylketonuria, glycogen storage diseases).
• Acid-base balance and electrolyte disorders.
• Liver and kidney function tests.

8. Special Topics in Biochemistry

Advanced topics in biochemistry include:

• Vitamins and Minerals: Roles as cofactors and coenzymes, deficiency diseases.
• Immunochemistry: Antibody structure, immune response, and complement system.
• Cancer Biochemistry: Oncogenes, tumor suppressors, and metabolic changes in cancer cells.
• Neurochemistry: Neurotransmitters and their pathways.
• Plant Biochemistry: Photosynthesis, nitrogen fixation, and secondary metabolites.