Biology - Chapter 12: Respiration in Plants
Understanding Glycolysis, Aerobic Respiration, and ATP Synthesis
1. Key Stages of Respiration
Cellular respiration is a multi-step process that occurs in the cytoplasm and mitochondria.
| Process | Location | Main Products |
|---|---|---|
| Glycolysis | Cytoplasm | 2 Pyruvate, 2 ATP, 2 NADH |
| Krebs Cycle | Mitochondrial Matrix | CO₂, ATP, NADH, FADH₂ |
| Electron Transport System (ETS) | Inner Mitochondrial Membrane | ATP, H₂O |
💡 Quick Concept:
Glycolysis → Cytoplasm
Krebs Cycle → Matrix
ETS → Inner membrane
2. Important Questions & Answers
Q1. What is glycolysis? Why is it called EMP pathway?
Answer: Glycolysis is the first step of respiration where glucose breaks into two molecules of pyruvate.
It is called EMP pathway because it was discovered by Embden, Meyerhof, and Parnas.
Glycolysis Pathway
Q2. Difference between aerobic and anaerobic respiration?
Answer:
• Aerobic → Requires oxygen, produces 36–38 ATP
• Anaerobic → No oxygen, produces only 2 ATP
• Aerobic → Requires oxygen, produces 36–38 ATP
• Anaerobic → No oxygen, produces only 2 ATP
Q3. What is fermentation? Types?
Answer:
Fermentation is incomplete oxidation of pyruvate in absence of oxygen.
• Alcoholic fermentation → Ethanol + CO₂
• Lactic acid fermentation → Lactic acid
Fermentation is incomplete oxidation of pyruvate in absence of oxygen.
• Alcoholic fermentation → Ethanol + CO₂
• Lactic acid fermentation → Lactic acid
Q4. What is Respiratory Quotient (RQ)?
Answer: RQ = CO₂ released / O₂ consumed
Carbohydrates → 1
Fats → 0.7
Proteins → 0.9
Carbohydrates → 1
Fats → 0.7
Proteins → 0.9
Q5. Function of ATP Synthase (F₀-F₁ particles)?
Answer: It helps in ATP formation by using proton gradient across mitochondrial membrane.
Q6. Why is Krebs cycle called amphibolic pathway?
Answer: Because it is involved in both catabolism (breakdown) and anabolism (synthesis).
🔥 Exam Booster:
Glycolysis = 2 ATP
Aerobic = High energy
Anaerobic = Low energy
Krebs = Central pathway