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Foundation Sciences · Biochemistry

Free Radicals and Oxidative Stress

⏱️ 45–60 minutes read 📖 Biochemistry

ROS generation, antioxidant defences (SOD, catalase, glutathione, vitamins C/E) and disease links.

📌 Learning Objectives

  • Describe the key principles of free radicals and oxidative stress.
  • Explain the clinical relevance of free radicals and oxidative stress.
  • Recognise common conditions linked to free radicals and oxidative stress in MLA-style scenarios.

📋 Overview

ROS generation, antioxidant defences (SOD, catalase, glutathione, vitamins C/E) and disease links. This topic integrates with pathology, pharmacology and clinical medicine and is frequently tested in UK medical school exams and the MLA.

🔬 Basic Science

ROS generation, antioxidant defences (SOD, catalase, glutathione, vitamins C/E) and disease links. Detailed mechanisms, regulation and molecular interactions underpin both normal physiology and disease.

🏥 Clinical Relevance

Paracetamol overdose, G6PD haemolysis, atherosclerosis, neurodegeneration.

🧪 Investigations

Relevant laboratory tests, imaging or histological examination are used as appropriate to the clinical context.

💊 Management

Management is condition-specific; principles include addressing the underlying biochemical/structural derangement, supportive care and targeted therapy where available.

Revision Resources – expand the sections below for high-yield notes, exam pearls, key facts and further reading.

🎯 MLA High-Yield Notes & Quick Revision
High-yield topic for the UK MLA — frequently appears in SBA questions linking biochemistry concepts to clinical presentations and management decisions.
Applying biomedical science to clinical practice Diagnosis and investigation Pathophysiology of common conditions
  • ROS generation, antioxidant defences (SOD, catalase, glutathione, vitamins C/E) and disease links.
Exam Pearls
⭐ High Yield
Mitochondrial ETC main ROS source
Glutathione (GSH) recycled by NADPH
Reperfusion injury post-ischaemia
Paracetamol depletes glutathione → NAC rescue
💡 Clinical Pearl
: Paracetamol overdose, G6PD haemolysis, atherosclerosis, neurodegeneration.
⚠️ Exam Tip — Common Mistakes
Confusing free radicals and oxidative stress with related but distinct mechanisms.
Memorising pathways without linking to clinical disease.
🔑 Key Facts
Mitochondrial ETC main ROS source
Glutathione (GSH) recycled by NADPH
Reperfusion injury post-ischaemia
Paracetamol depletes glutathione → NAC rescue
📚 References
  1. BMJ Best Practice
  2. Robbins Basic Pathology
  3. Lippincott Illustrated Reviews: Biochemistry
  4. Wheater's Functional Histology
  5. NICE guidance where applicable.

Further Resources

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