Carbohydrate Metabolism – MBBS 


🔹 Introduction


Carbohydrates are the main source of energy for our body. Daily diet me approx. 60–70% energy carbohydrates se aati hai.

Unka metabolism ka main aim hota hai Glucose ka breakdown karke ATP (energy) banana.


🔹 Major Steps in Carbohydrate Metabolism


1. Glycolysis (Embden-Meyerhof Pathway)


Location: Cytoplasm


Function: Glucose (6C) → 2 Pyruvate (3C) + ATP + NADH


Net Gain: 2 ATP + 2 NADH per glucose

👉 Ye pathway aerobic & anaerobic dono condition me chal sakta hai.



2. Citric Acid Cycle (Krebs Cycle / TCA Cycle)


Location: Mitochondria


Function: Pyruvate → Acetyl-CoA → CO₂ + NADH + FADH₂


Net Gain (per acetyl-CoA): 3 NADH, 1 FADH₂, 1 GTP

👉 Ye ek amphibolic pathway hai (catabolic + anabolic dono).



3. Electron Transport Chain (ETC) & Oxidative Phosphorylation


Location: Inner mitochondrial membrane


Function: NADH/FADH₂ se electrons → ATP synthesis


Net Gain: ~34 ATP per glucose

👉 Yahi stage me maximum ATP banti hai.



4. Glycogenesis


Location: Liver & Muscle


Function: Glucose → Glycogen (storage form)

👉 Jab blood glucose high ho, insulin promote karta hai glycogenesis.



5. Glycogenolysis


Function: Glycogen → Glucose


Hormonal regulation: Glucagon & Epinephrine

👉 Fasting ya stress me important.



6. Gluconeogenesis


Function: Non-carbohydrate sources (lactate, amino acids, glycerol) → Glucose


Location: Mainly Liver

👉 Ye process fasting/starvation me blood glucose maintain karta hai.




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🔹 Energy Yield from Complete Oxidation of Glucose


Glycolysis: 2 ATP + 2 NADH


TCA Cycle: 2 GTP + 6 NADH + 2 FADH₂


ETC (oxidation of NADH & FADH₂): ~34 ATP

👉 Total = 36–38 ATP per glucose




🔹 Clinical Importance


1. Diabetes Mellitus – defect in insulin action leads to abnormal glucose metabolism.



2. Glycogen Storage Disorders (GSDs) – deficiency of enzymes in glycogen metabolism.



3. Hypoglycemia – imbalance between glucose production & utilization.




🔹 Conclusion


Carbohydrate metabolism ek central metabolic pathway hai jo body ke liye continuous energy supply karta hai. Iske har step ka regulation hormones aur enzymes se hota hai. MBBS aur paramedical students ke liye iski understanding clinical practice me kaafi important hai.




Here’s the Carbohydrate Metabolism Flow Chart you can directly add to your blog.
It shows the main pathway (Glucose → Glycolysis → Pyruvate → TCA Cycle → ETC → Energy) along with side pathways (Glycogenesis, Glycogenolysis, Gluconeogenesis).