20 Most-Important Words (Meanings in Hindi)

• Nutrition — पोषण: भोजन लेने व शरीर में उपयोग करने की प्रक्रिया
• Nutrients — पोषक तत्व: कार्बोहाइड्रेट, प्रोटीन, वसा, विटामिन, खनिज आदि
• Autotrophs — स्वपोषी: जो सरल पदार्थों से स्वयं भोजन बनाते हैं
• Heterotrophs — परपोषी: जो अपना भोजन स्वयं नहीं बनाते
• Photosynthesis — प्रकाश संश्लेषण: सूर्य के प्रकाश में भोजन बनाना
• Chlorophyll — हरितलवक/हरितवर्णक: पत्तियों का हरा रंग देने वाला रंगद्रव्य
• Stomata — रंध्र: पत्तियों पर सूक्ष्म छिद्र, गैसों का आदान-प्रदान
• Guard cells — रक्षक कोशिकाएँ: रंध्र को खोलना-बंद करना
• Vessels — वाहिकाएँ: जड़ों से पत्तियों तक जल-खनिज ले जाने वाली नलियाँ
• Carbohydrates — कार्बोहाइड्रेट: ऊर्जा देने वाले पदार्थ, जैसे स्टार्च
• Proteins — प्रोटीन: शरीर की वृद्धि व मरम्मत के लिए
• Fats — वसा: ऊर्जा का संकेंद्रित स्रोत
• Parasite — परजीवी: दूसरे पौधे/जीव पर आश्रित
• Host — आतिथि पौधा/पोषक: जिस पर परजीवी निर्भर होता है
• Saprotroph — अपघटी/सैप्रोट्रोफ: मृत-सड़े पदार्थ से पोषण लेने वाला
• Insectivorous plant — कीटकभक्षी पौधा: कीट पकड़कर पोषण लेने वाला
• Algae — शैवाल: पानी में पाए जाने वाले हरे सूक्ष्म जीवसमूह
• Rhizobium — राइजोबियम: वायुमंडलीय नाइट्रोजन को उपयोगी रूप में बदलने वाला बैक्टीरिया
• Symbiosis — परस्पर सहजीवन: साथ रहकर दोनों का लाभ
• Lichen — लाइकेन: शैवाल + फफूंद का सहजीवी संघ

Important Notes for Quick Revision

20 Most-Important One-Word Answer Type (Answer in 1–2 lines)

1. The organisms that make their own food are called?
   Autotrophs — they synthesise food from CO\(_2\) and H\(_2\)O using sunlight and chlorophyll.
2. The green pigment in leaves is?
   Chlorophyll — captures solar energy for photosynthesis.
3. Tiny pores on leaf surface are?
   Stomata — allow exchange of CO\(_2\) and O\(_2\).
4. Food produced in photosynthesis first forms a carbohydrate called?
   Starch/Glucose — stored commonly as starch.
5. Organism living on a host and drawing food?
   Parasite.
6. Host-independent mode using dead matter?
   Saprotrophic nutrition.
7. Yellow wiry parasitic plant commonly called Amarbel?
   Cuscuta.
8. Plants that trap insects are called?
   Insectivorous plants (e.g., pitcher plant).
9. Green patches on still water are mostly?
   Algae.
10. Bacteria fixing atmospheric nitrogen in legume roots?
    Rhizobium.
11. Part of cell controlling activities?
    Nucleus.
12. Jelly-like substance inside cell?
    Cytoplasm.
13. Outer thin boundary of cell?
    Cell membrane.
14. Process of plants making food using light?
    Photosynthesis.
15. Ultimate source of energy for living beings?
    Sun.
16. Photosynthesis mainly occurs in which plant organ?
    Leaves (also other green parts).
17. Leaf pores are guarded by which cells?
    Guard cells.
18. Transport of water and minerals in plants occurs via?
    Vessels (xylem vessels).
19. Partnership where both organisms benefit?
    Symbiosis.
20. Combined body of alga and fungus living together?
    Lichen.

20 Very Short Answer Type Questions (1–2 lines)

1. Why are plants called autotrophs?
   Because they synthesise food from simple inorganic substances using sunlight.
2. Name the raw materials of photosynthesis.
   Carbon dioxide and water (with minerals); sunlight and chlorophyll are essential.
3. What is the role of chlorophyll?
   It traps solar energy needed to drive photosynthesis.
4. Where do plants get water and minerals from?
   From soil via roots; transported by vessels to leaves.
5. Which gas enters and which gas leaves during photosynthesis?
   CO\(_2\) enters; O\(_2\) is released.
6. How do red/brown leaves photosynthesise?
   They contain chlorophyll masked by other pigments; photosynthesis still occurs.
7. What indicates that photosynthesis has occurred in a leaf?
   Iodine test showing starch formation (blue-black colour).
8. Why do desert plants have green stems?
   Leaves are reduced to spines; green stems carry out photosynthesis.
9. Define parasite with one example.
   An organism depending on a host for food; e.g., Cuscuta.
10. Why do insectivorous plants trap insects?
    To obtain nitrogen and minerals from insect bodies.
11. Give one saprotroph example.
    Fungi (bread mould, mushrooms).
12. What are fungal spores?
    Reproductive bodies of fungi present in air; germinate on warm, moist surfaces.
13. What is symbiosis? Give one example.
    Mutual association; e.g., lichens (alga + fungus).
14. How is soil nitrogen replenished naturally?
    By nitrogen-fixing bacteria like Rhizobium in legume roots.
15. Name the cell parts visible under a simple diagram in this chapter.
    Cell membrane, cytoplasm, nucleus.
16. What do vessels form inside a plant?
    A continuous pipeline from roots to leaves for transport.
17. Which energy is converted during photosynthesis?
    Solar energy → chemical energy (in food).
18. Why are humans called heterotrophs?
    They depend on plants/animals for food; cannot synthesise their own.
19. What is the product stored in leaves after photosynthesis?
    Starch (a carbohydrate).
20. Name the tiny hair-like structures in pitcher that trap insects.
    Downward-directed hairs inside the pitcher.

20 Short Answer Type Questions (about 2–3 lines)

1. Explain autotrophic nutrition.
   It is the mode in which organisms (green plants) make organic food from CO\(_2\) and H\(_2\)O using sunlight and chlorophyll. They are called autotrophs.
2. How do stomata help in photosynthesis?
   They open to take in CO\(_2\) and release O\(_2\); guard cells regulate opening/closing to control gas exchange and water loss.
3. Describe the transport of raw materials to leaves.
   Roots absorb water/minerals → xylem vessels carry them upward; CO\(_2\) reaches leaf through stomata.
4. Write the balanced chemical equation of photosynthesis.
   \[ 6\mathrm{CO}_2 + 12\mathrm{H_2O} \xrightarrow[\text{chlorophyll}]{\text{sunlight}} \mathrm{C_6H_{12}O_6} + 6\mathrm{O_2} + 6\mathrm{H_2O} \]
5. Why is the Sun called the ultimate source of energy?
   Plants capture solar energy to make food; all organisms obtain energy directly or indirectly from this food.
6. How can we test a leaf for starch?
   Boil leaf, decolorise in alcohol, rinse, then add iodine. Blue-black colour indicates starch.
7. Why do some plants show red/violet leaves?
   Other pigments (anthocyanins) mask green; chlorophyll is still present, so photosynthesis occurs.
8. What is the role of Rhizobium in legume roots?
   It fixes atmospheric N\(_2\) into soluble forms usable by plants; plants provide it food and shelter (symbiosis).
9. Differentiate between parasite and saprotroph (in brief).
   Parasite lives on/inside a living host and takes food (e.g., Cuscuta). Saprotroph feeds on dead/decaying matter (e.g., fungi).
10. Why do insectivorous plants trap insects if they are green?
    They photosynthesise but grow in nitrogen-poor soils; insects supply nitrogen and minerals.
11. State one reason fungi suddenly appear during rains.
    Warm, moist conditions favour spore germination and rapid growth on organic matter.
12. What is symbiosis? Give two examples from the chapter.
    Mutual association: lichens (alga + fungus); fungi with plant roots exchanging water/minerals for food.
13. How do vessels help a plant?
    They form a continuous pipeline (xylem) transporting water and minerals from roots to leaves where food is made.
14. Name the cell parts shown in the chapter’s simple cell diagram and their functions.
    Cell membrane (boundary), cytoplasm (jelly-like medium), nucleus (control centre).
15. Why must soil nutrients be replenished?
    Crop uptake depletes nutrients; manures/fertilisers and biological N-fixation restore them for healthy growth.
16. Explain how algae make their own food.
    Algae contain chlorophyll (green); in presence of sunlight they photosynthesise like plants.
17. What happens inside the pitcher plant when an insect falls in?
    Lid closes; downward hairs trap insect; digestive juices break it down; nutrients are absorbed.
18. How do farmers benefit from growing legumes before cereals?
    Legumes enrich soil nitrogen via Rhizobium, reducing nitrogenous fertiliser need for the next crop.
19. Give one reason why covered leaf patches fail the starch test.
    No sunlight → no photosynthesis → no new starch in covered region.
20. What products of photosynthesis are useful to living beings?
    Carbohydrates (food/energy) and oxygen (respiration) essential for survival.

NCERT Textbook Exercise – Perfect Answers

1. 1. Why do organisms take food?
   To obtain energy for all activities, for growth, repair of body tissues, and to maintain life processes.
2. 2. Distinguish between a parasite and a saprotroph.
   Parasite: Lives on/in a living host and takes its food (e.g., Cuscuta). Saprotroph: Obtains nutrition from dead and decaying matter by secreting digestive juices and absorbing the nutrients (e.g., fungi).
3. 3. How would you test the presence of starch in leaves?
   Boil a leaf, decolourise it in alcohol in a hot water bath, rinse with water, then add iodine solution. Blue-black colour confirms starch.
4. 4. Give a brief description of the process of synthesis of food in green plants.
   Chlorophyll in leaves traps sunlight to convert CO\(_2\) (from air via stomata) and H\(_2\)O (from soil via roots) into carbohydrates, releasing O\(_2\). Balanced equation: \[ 6\mathrm{CO}_2 + 12\mathrm{H_2O} \xrightarrow[\text{chlorophyll}]{\text{sunlight}} \mathrm{C_6H_{12}O_6} + 6\mathrm{O_2} + 6\mathrm{H_2O}. \]
5. 5. Show with the help of a sketch that plants are the ultimate source of food.
   All food chains start with green plants (producers) that capture solar energy to make food. Herbivores eat plants; carnivores/omnivores depend on herbivores—thus, all depend on plants.
6. 6. Fill in the blanks:
   (a) Green plants are called autotrophs since they synthesise their own food.
   (b) The food synthesised by plants is stored as starch.
   (c) In photosynthesis solar energy is absorbed by the pigment called chlorophyll.
   (d) During photosynthesis plants take in carbon dioxide and release oxygen gas.
7. 7. Name the following:
   (i) A parasitic plant with yellow, slender and branched stem — Cuscuta (Amarbel).
   (ii) A plant that is partially autotrophic — Pitcher plant (insectivorous).
   (iii) The pores through which leaves exchange gases — Stomata.
8. 8. Tick the correct answer:
   (a) Cuscuta is an example of: (ii) parasite.
   (b) The plant which traps and feeds on insects is: (iii) pitcher plant.
9. 9. Match the items in Column I with Column II.
   Chlorophyll → Leaf
   Nitrogen → Rhizobium
   Cuscuta → Parasite
   Animals → Heterotrophs
   Insects → Pitcher plant
10. 10. Mark ‘T’ or ‘F’:
    (i) Carbon dioxide is released during photosynthesis. — F (CO\(_2\) is used; O\(_2\) is released).
    (ii) Plants which synthesise their food are called saprotrophs. — F (they are autotrophs).
    (iii) The product of photosynthesis is not a protein. — T (primary product is carbohydrate).
    (iv) Solar energy is converted into chemical energy during photosynthesis. — T.
11. 11. Which part of the plant takes in carbon dioxide for photosynthesis?
    Stomata on leaves.
12. 12. Plants take carbon dioxide from the atmosphere mainly through their:
    Leaves (via stomata).
13. 13. Why do farmers grow many fruits and vegetable crops inside large green houses? Advantages?
    Greenhouses control light, temperature, humidity and CO\(_2\) to optimise photosynthesis and growth, protect from pests/weather, and increase yield & quality.

Formula Reminder

Photosynthesis (simple form): \(\text{Carbon dioxide} + \text{Water} \xrightarrow[\text{chlorophyll}]{\text{sunlight}} \text{Carbohydrate} + \text{Oxygen}\)

Balanced (molecular) form: \(6\mathrm{CO}_2 + 12\mathrm{H_2O} \rightarrow \mathrm{C_6H_{12}O_6} + 6\mathrm{O_2} + 6\mathrm{H_2O}\)