Worksheet Solutions: Classification of Plants | Biology Class 7 ICSE PDF Download

Part A — Multiple Choice Questions 

Q1. In which kingdom do prokaryotic, single-celled organisms with a nucleoid (no true nucleus) belong?

(a) Protista

(b) Monera

(c) Fungi

(d) Plantae
Answer: (b) Monera
Explanation: Members of Monera (such as bacteria) are single-celled and lack a nuclear membrane; their DNA lies in a nucleoid region.

Q2. The tiny “false feet” that help Amoeba move and capture food are called

(a) Cilia

(b) Flagella

(c) Pseudopodia

(d) Hyphae
Answer: (c) Pseudopodia
Explanation: Amoeba pushes out parts of its cell membrane and cytoplasm to form pseudopodia, used for movement and surrounding food.

Q3. In bread mould, the round structure at the tip that holds spores is the

(a) Mycelium

(b) Hypha

(c) Sporangium

(d) Capsule
Answer: (c) Sporangium
Explanation: Thread-like hyphae form a network (mycelium). Erect hyphae develop sporangia at the tips, which release spores.

Q4. Which statement correctly distinguishes algae and fungi?

(a) Both have chlorophyll and make food

(b) Algae lack chlorophyll; fungi have chlorophyll

(c) Algae have chlorophyll (make food); fungi lack chlorophyll (feed on dead matter)

(d) Both are animals
Answer: (c)
Explanation: Algae are photosynthetic (chlorophyll present). Fungi are saprophytes; they absorb nutrients from dead and decaying material.

Q5. Plants that bear seeds not enclosed in fruits (often in cones) are

(a) Angiosperms

(b) Ferns

(c) Mosses

(d) Gymnosperms
Answer: (d) Gymnosperms
Explanation: Gymnosperms produce naked seeds (no fruit). Angiosperms have seeds inside fruits.

Part B — Short Answer Questions

Q6. What is classification? Give two advantages.
Answer: Classification is grouping living things by shared features.
Advantages:

1. Studying a few members reveals traits of the whole group.

2. Shows relationships and helps in identifying organisms.
   Explanation: With millions of species, grouping by similarities makes learning systematic and helps us see how forms may have developed from simpler to complex ones.

Q7. Name any two shapes of bacteria and one place they can be found.
Answer: Shapes: Coccus (spherical), Bacillus (rod-shaped), Spirillum (spiral), Vibrio (comma-shaped).
Found in: air, water, soil, and even inside humans, plants, and animals.
Explanation: Bacteria are tiny and simple, widespread in many habitats and can tolerate extreme conditions.

Q8. How does Amoeba obtain food?
Answer: Amoeba moves toward food, extends pseudopodia around it, forms a food vacuole, digests it with juices, absorbs soluble nutrients, and throws out the rest.
Explanation: Digestion happens inside the vacuole, protecting the rest of the cytoplasm.

Q9. What is saprophytic nutrition in fungi? Give one example.
Answer: Fungi secrete digestive juices on dead matter, then absorb the simple nutrients.
Example: Bread mould feeding on stale bread.
Explanation: This is external digestion, followed by absorption through hyphae; nutrients are often stored as glycogen.

Q10. State two differences between gymnosperms and angiosperms.
Answer:

• Gymnosperms: Seeds are naked (no fruit); many are evergreen; seeds often in cones (for example, pine).

• Angiosperms: Bear flowers; seeds are inside fruits (for example, mango).
  Explanation: The presence of flowers and fruits is a key feature of angiosperms; gymnosperms lack fruits.

Part C — Long Answer Questions

Q11. Describe the structure of a typical bacterium and list useful and harmful roles of bacteria.

Stepwise Solution:

1. Cell type: Single-celled, prokaryotic; DNA lies in a nucleoid (no nuclear membrane).

2. Coverings: Cell wall (rigid, not cellulose-based); many have an outer capsule.

3. Cell parts absent: No nucleolus, mitochondria, or plastids.

4. Food store: Often stores glycogen.

5. Useful roles:

   • Medicines: Production of antibiotics (for example, streptomycin); vaccines from killed or weakened bacteria.

   • Food industry: Curd formation (Lactobacillus), vinegar from fruit juices (Acetobacter).

   • Agriculture/industry: Retting of jute, tanning leather, making compost and manure, biogas from sewage.

6. Harmful roles:

   • Food spoilage: Milk, meat, and vegetables go bad.

   • Diseases: Can cause cholera, typhoid, TB, pneumonia, and others.
     Conclusion: Bacteria are structurally simple but have major benefits and risks; proper use and hygiene are important.

Q12. Explain the life activities of Amoeba: movement, feeding, respiration, excretion, and reproduction.

Stepwise Solution:

1. Movement: Uses pseudopodia (“false feet”)—temporary bulges of cytoplasm—to creep in water.

2. Feeding: Moves toward food, engulfs it with pseudopodia, makes a food vacuole, digests it, absorbs nutrients, and throws out the leftovers.

3. Respiration: Oxygen diffuses in through the cell membrane; carbon dioxide diffuses out into the water.

4. Excretion: Ammonia (main waste) diffuses out; excess water collects in a contractile vacuole, which fills and empties to maintain balance.

5. Reproduction:

   • Binary fission: The nucleus divides; the cell splits into two similar amoebae.

   • Cyst (unfavourable times): Forms a thick wall; inside, the nucleus may divide many times (multiple fission). When conditions improve, small amoebulae are released and grow.
     Conclusion: Even a single cell like Amoeba performs all basic functions of life using simple structures.

Q13. Compare the major plant groups: algae, mosses, ferns, gymnosperms, and angiosperms. Give features and examples.

Stepwise Solution:

1. Algae: Mostly live in water; single-celled or multicellular; green due to chlorophyll; make their own food.

   • Example: Spirogyra.

2. Mosses (Bryophyta): Form green velvety layers in moist places; have stem- and leaf-like parts but no true roots (use rhizoids); need water for reproduction (called amphibians of plant kingdom).

3. Ferns (Pteridophyta): Have true roots, stems, and leaves; do not produce flowers or seeds; reproduce by spores on the underside of leaves.

4. Gymnosperms: Seed-bearing plants without fruits; seeds often in cones; many are evergreen.

   • Examples: Pine, fir, cedar, spruce.

5. Angiosperms: Flowering plants; seeds are inside fruits.

   • Examples: Mango, grass, sugarcane, cashew.
     Conclusion: Plant groups differ by body structure and how they reproduce—from simple algae and mosses, to ferns with spores, to seed plants (gymnosperms and angiosperms).