Class 9 Biology: Chapter 01 Protectors of Biosphere - Questions and Answers
Study Notes for Class 9th Biology: Protectors of Biosphere | Text Books Solution Biology (English Medium) Biology: Chapter 01 ജീവമണ്ഡലത്തിന്റെ സംരക്ഷകർ
SCERT Solutions for Std IX Biology Chapterwise
Class 9 Biology Questions and Answers
Chapter 1: Protectors of Biosphere
1. What are the important services offered by plants?
• Provide food
• Provide oxygen
• Purify atmospheric air by absorbing CO₂ and releasing O₂.
• Reduce global warming by absorbing CO₂.
• Cool the atmosphere...
2. The process by which plants regulate the level of oxygen and carbon dioxide in the atmosphere?
- Photosynthesis.
3. Through the process ---------, the plants absorb and convert solar energy and fix it as chemical energy in the food that can be consumed by animals.
- Photosynthesis.
4. Define photosynthesis.
- The process of making food by green plants from water and carbon dioxide, with the help of sunlight.
5. The organ of photosynthesis? The kitchen of the biosphere?
- Leaf.
6. Why is the lower part of a leafless green in colour?
- More chloroplasts, containing chlorophyll, are seen on the upper part of the leaf than on the lower part.
7. Factors needed for photosynthesis?
• Sunlight - (for breaking water molecules into hydrogen and oxygen)
• Pigments like chlorophyll – (to absorb sunlight)
• Water and Carbon dioxide - (used as the raw material for synthesising food).
• Minerals and salts- (used as the raw material for synthesising food).
8. What are the pigments present in the chloroplast?
Mainly Chlorophyll a.
Chlorophyll b, Carotene and xanthophyll are accessory pigments.
9. Why are certain pigments known as 'accessory pigments'?
- They absorb sunlight and transfer it to the chlorophyll a.
10. Structure of chloroplast?
- A chloroplast is a double membranous cell organelle with the fluid called stroma and many packs of membranous sacs called grana, embedded in it. More pigments are seen in grana.
11. Phases or stages of photosynthesis?
a) – Light Reaction (The phase which requires light)
Water splits into hydrogen and oxygen. Light energy is converted into chemical energy (stored as ATP molecules). The light reaction occurs inside the grana of the chloroplast. During this phase, O2 is released.
b) – Dark Reaction (The phase which does not require light) or Calvin cycle. Using the energy of ATP, Hydrogen combines with CO2 to form glucose (carbohydrate). This phase takes place in the stroma of the chloroplast.
12. The dark reaction of photosynthesis known as the 'Calvin cycle'. Why?
- The scientist, Melvin Calvin discovered the cyclic chemical reactions in the dark phase and hence, the phase is also known as the 'Calvin cycle'. He was awarded the Nobel Prize in 1961 for this discovery.
13. Glucose, the product of photosynthesis, is converted into starch. Why?
- Since glucose is readily soluble in water, it can not be stored. Hence it is converted into insoluble starch.
14. The converted starch (sucrose) is transported through ----------- to various parts to store in different forms.
- Phloem.
15. In what ways the synthesized glucose is stored in different parts of plants, after metabolic activities?
16. Give examples of plant products having economic importance.
- Coffee, Cocoa, Pepper, Rubber latex, Cardamom ...
17. The process of making energy from chemical compounds by certain organisms without the help of solar energy is known as ------------
- Chemosynthesis. ( eg: Sulphur bacteria can produce energy by oxidising inorganic compound)
18. About 70-80% of oxygen in the atmosphere is contributed by ---------- present in the ocean ecosystem.
- Algae and phytoplankton.
19. Who are the chief producers of the ocean ecosystem?
- Algae and phytoplankton.
20. Suggest an experiment to prove the release of oxygen molecules during photosynthesis.
- Take a piece of aquatic plant like hydrilla in a glass tumbler, filled with water. Cover the plant using a transparent funnel. Cover the tail portion of the funnel with a test tube filled with water. Take care to leave a little portion of the tube devoid of water (see the figure).
Keep this device under sunlight for one hour. Observe the air bubbles going upward. The gas is oxygen (released from water molecules during the light phase).21. Why plants are called 'the lungs of the earth'?
- Plants offer great service to the biological world by absorbing CO₂ from the atmosphere and releasing oxygen and thus purify the air.
22. Give a few examples of how plants serve in the mitigation of natural disasters.
- To some extend, mangrove forests control Tsunami. Plants like bamboo, reed (ദര്ഭ), vetiver(രാമച്ചം) and lemongrass protect the river banks. Trees and bushes prevent soil erosion and landslide.
23. Make apt slogans for the awareness of reducing global warming.
• Trees – A Solution for Global warming.
• Protect the Green world for a Carbon-free world.
24. "Plants are Miracles of Earth". Analyse this statement and justify your opinion
• In photosynthesis, green plants use CO₂ and are released O₂.
• It helps maintain the regular CO₂ -O₂ ratio of the atmosphere. Saves energy. Making food
👉 Quiz
PSC Solved Question Papers ---> Click here
PSC TODAY's EXAM RESULTS ---> Click here
PSC EXAM PROGRAMME -> Click here
CURRENT AFFAIRS QUESTIONS -> Click here
PSC Degree Level Questions & Answers - Click here
PSC 10th, +2 Level Questions & Answers - Click here
PSC SHORTLISTS -> Click here
PSC RANK LISTS -> Click here
 Chapter 01 Protectors of Biosphere){kind=link}
0 Comments