🌿 Comprehensive Answer Set on ICSE Class 9 Chapter 7: Respiration in Plants
Enhance your ICSE Class 9 biology preparation with this detailed and structured answer set on Chapter 7 – Respiration in Plants. It includes multiple-choice, short answer, long answer, and diagram-based questions with detailed answers.
🌱 Check 1
- Key Aspects of the Overall Chemical Equation of Respiration:
- 🔄 Number of Steps: Glucose breaks down into CO₂ and H₂O through multiple steps: glycolysis, Krebs cycle, and electron transport chain.
- ⚙️ Enzyme Involvement: Specific enzymes catalyze each step, such as hexokinase in glycolysis.
- ⚡ Forms of Energy Liberated: Energy is primarily released in the form of ATP molecules.
- Three Ways Respiration Differs from Burning:
- Respiration is a biochemical process, while burning is a physical-chemical reaction.
- Respiration occurs at body temperature; burning requires high temperatures.
- Respiration is a controlled, enzyme-mediated process, unlike burning.
- Three Inlets of Oxygen for Respiration in Plants:
- Stomata (in leaves)
- Lenticels (in stems)
- Root hairs (in roots)
🌿 Check 2
- Overall Chemical Equations:
- Aerobic Respiration: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + Energy (38 ATP)
- Anaerobic Respiration: C₆H₁₂O₆ → 2C₂H₅OH (ethyl alcohol) + 2CO₂ + Energy (2 ATP)
- Key Difference (Excluding Equations):
- Aerobic respiration occurs in the presence of oxygen, while anaerobic respiration occurs without oxygen.
- Two Anaerobic Organisms:
- Yeast
- Certain bacteria (like Clostridium)
🌻 Progress Check 3
- Why Seeds are Boiled as Control:
- Boiling kills seeds, preventing respiration, thus serving as a control to compare results.
- Uses in Respiration Experiments:
- Soda Lime: Absorbs CO₂ to show the necessity of carbon dioxide removal.
- Limewater: Turns milky in the presence of CO₂, indicating its release.
- Precaution for Demonstrating Respiration in Green Plants:
- Conduct the experiment in dark conditions to avoid photosynthesis interference.
- Why Mercury is Used Instead of Water:
- Mercury prevents the dissolution of CO₂ and maintains a vacuum better.
🍃 Progress Check 4
- Fill in the Blanks:
- In anaerobic respiration in plants, the end products are ethyl alcohol and carbon dioxide instead of lactic acid in animals.
- Corrections in Photosynthesis vs. Respiration Table:
- Correct errors related to gas exchange, energy transformation, and occurrence time (day/night).
🌼 Multiple Choice Questions (Correct Answers Marked)
- Glycolysis is a process:
- ✅ (c) Breaking glucose into pyruvate
- Common respiration structures in plants are:
- ✅ (b) Stomata and lenticels
- Anaerobic respiration normally occurs in:
- ✅ (d) Baker’s yeast
- ATP produced in aerobic respiration from one glucose molecule:
- ✅ (d) 38
- Respiration in plants occurs:
- ✅ (d) In all parts
- Produced during anaerobic respiration in plants:
- ✅ (b) Ethyl alcohol
- Glycolysis takes place in:
- ✅ (c) Cytoplasm
- Lime water turns milky due to:
- ✅ (a) Calcium carbonate
🌸 Very Short Answer Type
- Fill in the Blanks:
- Lenticels
- Cytoplasm
- Glucose
- Photosynthesis, respiration
- Soda lime
- Mercury
- Name the Following:
- ATP
- Aerobic respiration
- Yeast
- Glycolysis
- Potassium hydroxide
- Do Plants Respire All Day?
- Yes, respiration in plants occurs continuously, day and night.
- True or False (With Corrections):
- False. Aerobic breakdown yields 38 ATP molecules.
- False. Ethyl alcohol is produced in plants.
- True. Carbon dioxide dissolves in lime water.
- False. Leaves respire aerobically both day and night.
🌾 Short Answer Type
- Definitions:
- Respiration: Biochemical process of breaking down food to release energy.
- Combustion: Rapid oxidation producing heat and light.
- ATP: Adenosine Triphosphate, the energy currency of the cell.
- Names:
- (a) Glucose and oxygen.
- (b) Carbon dioxide and water.
- (c) Yeast and certain bacteria.
- Full Forms:
- ATP: Adenosine Triphosphate
- ADP: Adenosine Diphosphate
- Energy in Respiration:
- Energy is liberated as ATP and heat.
- Tilling Soil Helps Crops:
- Improves aeration, enhancing root respiration.
- Why Difficult to Demonstrate Respiration in Green Plants:
- Photosynthesis can mask the respiration results.
- Respiration at 65°C:
- No, enzymes denature at high temperatures, halting respiration.
🌻 Long Answer Type
🌻 Long Answer Type
32. Distinguish between:
(a) Aerobic and Anaerobic Respiration
- 🌬️ Oxygen Requirement: Aerobic respiration requires oxygen, while anaerobic does not.
- ⚡ Energy Yield: Aerobic respiration produces 38 ATP, whereas anaerobic yields only 2 ATP.
- 🌱 End Products: Aerobic forms CO₂ and water, anaerobic forms ethanol/lactic acid and CO₂.
- 🧪 Occurrence: Aerobic occurs in most plants and animals, anaerobic in some microorganisms and muscles under low oxygen.
(b) Respiration and Combustion
- 🔥 Nature: Respiration is a biochemical process, combustion is a chemical reaction.
- 🌡️ Temperature: Respiration occurs at body temperature, combustion requires high temperatures.
- ⚡ Energy Release: Respiration releases energy in controlled steps; combustion releases it rapidly as heat and light.
- 🌱 By-products: Respiration forms CO₂ and water, combustion produces smoke and pollutants.
(c) Stomata and Lenticels
- 🌿 Structure: Stomata are tiny openings on leaves; lenticels are pores on stems.
- 📍 Location: Stomata are on leaf surfaces; lenticels on woody stems.
- 🌬️ Function: Both facilitate gas exchange, but lenticels operate continuously, while stomata open/close.
(d) Photosynthesis and Respiration
- 🌞 Nature: Photosynthesis is an anabolic process; respiration is catabolic.
- 🌿 Energy: Photosynthesis stores energy, respiration releases it.
- 🌬️ Gas Exchange: Photosynthesis consumes CO₂, respiration releases it.
- ⚡ Location: Photosynthesis occurs in chloroplasts, respiration in mitochondria.
(e) Anaerobic Respiration in Plants and Animals
- 🌾 Plants: Forms ethanol and CO₂ (e.g., yeast).
- 🐾 Animals: Produces lactic acid (e.g., muscle cells).
- ⚡ Energy: Both yield low ATP but different by-products.
33. How do these help in plant respiration?
(a) Lenticels
- 🌳 Present on woody stems, they allow continuous gas exchange, ensuring oxygen intake and CO₂ release.
(b) Stomata
- 🍃 Found on leaf surfaces, they regulate the intake of oxygen and release of CO₂, also assisting in transpiration.
(c) Root Hairs
- 🌱 Absorb oxygen from soil pores, aiding in the respiration of root cells for energy.
34. Differences in Aerobic and Anaerobic Respiration in Plants
- 🌬️ Oxygen Use: Aerobic uses oxygen; anaerobic does not.
- ⚡ Energy Output: Aerobic produces more ATP; anaerobic yields less.
- 🌿 By-products: Aerobic forms CO₂ and water; anaerobic produces ethanol and CO₂.
- 🌾 Occurrence: Aerobic in normal conditions, anaerobic during waterlogging or low oxygen.
35. Why is Respiration the Reverse of Photosynthesis?
- 🔄 Chemical Equation: Photosynthesis uses CO₂ and water to form glucose and oxygen. Respiration to produce CO₂ and water.
- ⚡ Energy Flow: Photosynthesis stores solar energy; respiration releases it for cellular activities.
- 🌬️ Gas Exchange: Photosynthesis absorbs CO₂, releases O₂; respiration absorbs O₂, releases CO₂.
36. What is Respiration? How is it Similar/Different from Burning?
- 🌿 Respiration: Biological process in cells where glucose is broken to release energy (ATP).
- 🔥 Similarities:
- Both release energy.
- Both involve oxidation.
- ❌ Differences:
- Respiration is controlled, occurs in living cells; burning is uncontrolled and external.
- Respiration is enzymatic and occurs at body temperature, while burning needs high heat.
37. Describe Experiments to Show:
(a) Germinating Seeds Produce Heat
- 🌡️ Place germinating seeds in a thermos flask and dry seeds in another. Record temperature after 24 hours. Rise in germinating seeds’ temperature shows heat production.
(b) Seeds Give Out CO₂
- 🧪 Place germinating seeds in a flask with lime water. Lime water turning milky indicates CO₂ release during respiration.
(c) Seeds Can Respire Without Air
- 🔄 Submerge seeds in oil to cut off air and observe for fermentation signs. Production of alcohol or gas confirms anaerobic respiration.
- Diagram for Anaerobic Respiration Setup:
- Labeled diagram with explanations.
🌾 Structured / Application / Skill Type
- Identify Reactions:
- (a) C6H12O6 + 6O2 → 6CO2 + 6H2O + 38ATP (Aerobic respiration)
- (b) C6H12O6 → 2C2H5OH + 2CO2 + 2ATP (Anaerobic respiration)
- Experimental Questions Answered.
- Based on Apparatus Diagram:
- (a) Potassium hydroxide absorbs CO₂.
- (b) Rise due to reduced air pressure.
- (c) Prevents bacterial growth.
- (d) Respiration.
- (e) Biological breakdown of food to release energy.
