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๐ฑ Introduction – Let’s Breathe in Energy!
Hello NEET aspirants ๐
Aaj hum start kar rahe hain ek aur high-weightage chapter – Respiration in Plants.
Jaise photosynthesis me energy store hoti hai, waise respiration me energy release hoti hai!
๐ก Simple definition:
> “Respiration is the process of oxidation of organic compounds (mainly glucose) to release energy (ATP).”
๐ NEET Biology Study Hub
Looking for more NCERT-focused Biology notes, diagrams, MCQs and NEET preparation resources?
Explore NEET Biology →Matlab plant food banata bhi hai aur use tod kar energy bhi leta hai — smart multitasking organism hai na? ๐ฟ๐
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⚡ 1. What Is Cellular Respiration?
Definition (NCERT-based):
> “Cellular respiration is a catabolic process in which organic compounds are broken down to release energy for cellular activities.”
Types:
1. Aerobic respiration – in presence of oxygen
2. Anaerobic respiration – in absence of oxygen
Overall equation:
C_6H_{12}O_6 + 6O_2 → 6CO_2 + 6H_2O + 686 kcal (energy)
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๐พ 2. Phases of Respiration
Respiration occurs in 3 major stages ๐
Stage Site Key Process End Product
Glycolysis Cytoplasm Glucose → Pyruvate 2 ATP, 2 NADH
Krebs Cycle (TCA) Mitochondrial Matrix Acetyl CoA oxidation 2 ATP, CO₂, NADH, FADH₂
Electron Transport Chain (ETC) Inner Mitochondrial Membrane NADH oxidation 34 ATP, H₂O
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๐งฉ 3. Glycolysis – The First Step of Respiration
Discovered by: Embden, Meyerhof & Parnas (EMP Pathway)
Site: Cytoplasm
Substrate: Glucose
End Product: 2 Pyruvate
Phases of Glycolysis:
1. Energy investment phase: 2 ATP used
2. Energy generation phase: 4 ATP produced
Net Gain:
ATP = 4 - 2 = 2, \quad NADH = 2
๐ก Trick: “2-in, 4-out = Net 2 ATP profit!”
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๐ฅ 4. Fate of Pyruvic Acid
Condition Process End Products Example
Aerobic Krebs cycle CO₂ + H₂O + Energy Plants, animals
Anaerobic Alcoholic fermentation Ethanol + CO₂ Yeast
Lactic acid fermentation Lactic acid Muscles, bacteria
๐ก Remember:
Aerobic = More ATP, Anaerobic = Less ATP
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๐ 5. Krebs Cycle (Citric Acid Cycle / TCA Cycle)
Discovered by: Sir Hans Krebs
Site: Mitochondrial matrix
Starting molecule: Acetyl CoA
End products (per glucose):
2 ATP
6 NADH
2 FADH₂
4 CO₂
๐ก Mnemonic:
Citrate – Isocitrate – ฮฑ-Ketoglutarate – Succinyl CoA – Succinate – Fumarate – Malate – Oxaloacetate
๐ Trick to remember: “Can I Keep Selling Sex For Money, Officer?” ๐
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⚡ 6. Electron Transport Chain (ETC)
Site: Inner mitochondrial membrane
Main steps:
NADH & FADH₂ donate electrons
Electrons move through complex I–IV
ATP formed by ATP synthase
Final electron acceptor = Oxygen (forms H₂O)
ATP yield: ~34 ATP
๐ก Overall total:
1 Glucose → 38 ATP (36 net)
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๐ฟ 7. Anaerobic Respiration
Occurs in absence of oxygen (in yeast or muscles).
Equation (in Yeast):
C_6H_{12}O_6 → 2C_2H_5OH + 2CO_2 + 2ATP
Equation (in Muscles):
C_6H_{12}O_6 → 2C_3H_6O_3 + 2ATP
๐ก Key difference:
Ethanol & CO₂ → Yeast
Lactic Acid → Muscles
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๐พ 8. Respiratory Quotient (RQ)
RQ = \frac{CO_2 \text{ evolved}}{O_2 \text{ consumed}}
Substrate RQ Value Example
Carbohydrates 1 Glucose
Fats < 1 Fatty acids
Proteins > 1 Organic acids
๐ก Trick: “Fat burns slow → RQ low”
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๐ฑ 9. Energy Yield Summary
Process ATP Produced
Glycolysis 2
Krebs Cycle 2
ETC 34
Total 38 ATP (36 Net)
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๐ฌ️ 10. Amphibolic Pathway
Respiration sirf energy release nahi karta, balki intermediate compounds biosynthesis me bhi use hote hain.
Example:
Acetyl CoA → Fatty acids
ฮฑ-Ketoglutarate → Amino acids
๐ก Meaning: Amphibolic = Catabolic + Anabolic
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๐ง 11. NEET PYQs (2018–2024)
Year Question Answer
2020 EMP pathway occurs in? Cytoplasm
2021 Number of ATP from 1 glucose? 36
2022 Final acceptor in ETC? Oxygen
2023 Where does Krebs cycle occur? Mitochondrial matrix
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๐ 12. Quick Revision Table
Step Site ATP Gain Main Product
Glycolysis Cytoplasm 2 Pyruvate
TCA Cycle Mitochondria 2 CO₂, NADH
ETC Inner membrane 34 ATP, H₂O
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๐ฏ 13. NEET Strategy
1. Revise all enzymes + locations + ATP yield.
2. Learn mnemonics for Krebs Cycle & ETC.
3. Practice PYQs (2016–2024).
4. Draw Glycolysis & TCA diagrams daily.
5. Understand difference between aerobic vs anaerobic clearly.
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๐ Related Blogs
☀️ Photosynthesis in Higher Plants – Day 50
๐ฟ Plant Growth and Development – Day 52
๐ธ Anatomy of Flowering Plants – Day 49
๐ฑ Transport in Plants – Day 20
๐ Mineral Nutrition – Day 21
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๐ Conclusion
Respiration in Plants ek conceptual + numerical chapter hai jahan se NEET me 2–3 questions regularly aate hain.
Bas yaad rakho bhai —