Pre-clinical medicine
Biochemistry
Biochemistry is the chemistry of life: how the body builds and breaks down molecules, makes energy and controls metabolism. It underpins understanding of neurotransmitters, nutrition, inherited metabolic disorders and the laboratory tests doctors order.
Depth by stage, Pre-U → Consultant (details)
What is it?
Biochemistry explains what happens inside cells: how food becomes energy, how proteins are made, how enzymes speed reactions and how hormones signal. It includes molecular biology (DNA and gene expression) and clinical biochemistry (blood tests).
Medical students learn key pathways such as glycolysis, the Krebs cycle and fat metabolism, and the diseases that occur when they fail, such as diabetes or inherited enzyme deficiencies.
Clinical biochemistry teaches how to interpret common blood results: kidney and liver function, electrolytes, glucose, lipids and thyroid tests.
Why does a psychiatrist need it?
Neurotransmitters such as serotonin, dopamine and noradrenaline are made from dietary amino acids by enzymes. Vitamin deficiencies (for example thiamine in alcohol use, B12 or folate) can cause confusion, memory problems or depression. Psychiatrists order and interpret blood tests before and during treatment, including lithium levels, kidney and thyroid function, lipids and glucose.
What level is expected at each stage?
Scale: 1. Aware → 2. Understands → 3. Applies → 4. Masters / Teaches. What the levels mean.
- Pre-UAwareAware of basic biological molecules from chemistry and biology.
- Pre-clinicalAppliesApplies knowledge of pathways and enzymes in exams and case discussions.
- ClinicalUnderstandsUnderstands how metabolic disease presents and what tests show.
- HousemanshipAppliesApplies clinical biochemistry daily when reading blood results.
- Medical officerUnderstandsUnderstands the biochemistry relevant to the posting.
- Psych traineeUnderstandsUnderstands neurotransmitter synthesis and metabolism, nutritional causes of mental symptoms, and monitoring tests.
- Specialist / consultantUnderstandsUnderstands and uses lab monitoring in complex cases.
What are the key topics?
Molecules and enzymes
- Amino acids and proteins
- Enzyme kinetics and inhibition (link to drugs such as MAO inhibitors)
- Carbohydrates and lipids
- Vitamins and coenzymes
Metabolism
- Glycolysis, Krebs cycle and oxidative phosphorylation
- Fat and protein metabolism
- Insulin, glucagon and blood sugar control
- Metabolism in fasting, feeding and starvation (link to eating disorders)
Molecular biology
- DNA replication and repair
- Gene expression and its regulation
- Laboratory techniques: PCR and sequencing (introduction)
Neurochemistry basics
- Synthesis of monoamines from tryptophan and tyrosine
- Glutamate and GABA metabolism
- Alcohol metabolism and its consequences
- Thiamine deficiency and Wernicke encephalopathy
Clinical biochemistry
- Renal function and electrolytes
- Liver function tests
- Thyroid function tests
- Lipid profile and HbA1c
- Therapeutic drug monitoring (introduction)
How is it learned and assessed?
- Lectures, PBL and laboratory practicals
- MCQ and short-answer examinations
- Case-based questions on metabolic disease
- Neurochemistry revisited in psychiatry basic sciences exams
Typical textbooks and resources
- Lippincott Illustrated Reviews: Biochemistry — Wolters Kluwer
- Harper's Illustrated Biochemistry — McGraw Hill
- Marks' Basic Medical Biochemistry — Wolters Kluwer
- Clinical Biochemistry: Lecture Notes — Wiley-Blackwell
Titles are widely used examples; editions change. Use university libraries or legitimate purchases.
Common questions
How is biochemistry used in psychiatry?
In two main ways: understanding how brain chemicals are made and how medicines change them, and interpreting blood tests used to check safety, such as kidney, liver, thyroid and lithium levels.
Can a vitamin deficiency cause mental symptoms?
Yes. Lack of thiamine, vitamin B12 or folate, among others, can cause confusion, memory problems or low mood. Doctors check for these when assessing patients.