Plant Kingdom - Exercise

Subject: Biology
Class: 11
Topic: Plant Kingdom

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Section A: Multiple Choice Questions (MCQs)

1. Artificial systems of classification were based mainly on: a) Natural affinities b) Evolutionary relationships c) Vegetative characters d) Cytological information

2. Pyrenoids are found in the chloroplasts of: a) Red algae b) Brown algae c) Green algae d) Mosses

3. Agar is obtained from: a) Volvox b) Sargassum c) Gelidium d) Dictyota

4. Which of the following are called 'amphibians of the plant kingdom'? a) Algae b) Bryophytes c) Pteridophytes d) Gymnosperms

5. The first terrestrial plants to possess vascular tissues are: a) Bryophytes b) Pteridophytes c) Gymnosperms d) Angiosperms

6. The dominant phase in the life cycle of pteridophytes is: a) Gametophyte b) Sporophyte c) Prothallus d) Zygote

7. Selaginella and Salvinia are: a) Homosporous b) Heterosporous c) Non-vascular d) Aquatic only

8. Gymnosperms are called 'naked-seeded' because: a) They have no seeds b) Seeds are not enclosed in fruits c) They have no fruits d) Both b and c

9. Mycorrhiza is found in the roots of: a) Cycas b) Pinus c) Cedrus d) Sequoia

10. The smallest angiosperm is: a) Eucalyptus b) Wolffia c) Pinus d) Marchantia

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Section B: NCERT Textbook Exercises (Questions & Answers)

1. What is the basis of classification of algae? Answer: Algae are classified into three main classes (Chlorophyceae, Phaeophyceae, Rhodophyceae) based on the type of photosynthetic pigments they possess, the nature of stored food material, and the composition of their cell wall.

2. When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm? Answer:

• Liverwort and Moss (Bryophytes): Takes place in the capsule of the sporophyte to produce haploid spores.
• Fern (Pteridophytes): Takes place in the sporangia of the sporophyte to produce haploid spores.
• Gymnosperm and Angiosperm: Takes place in the microsporangia (producing pollen/microspores) and megasporangia (producing megaspores) during the formation of gametophytes.

3. Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them. Answer: Bryophytes, Pteridophytes, and Gymnosperms bear archegonia. Example (Bryophytes): The gametophyte is the dominant phase. It produces male (antheridia) and female (archegonia) sex organs. Fusion of gametes in water forms a zygote, which grows into a sporophyte (attached to gametophyte). Meiosis in the sporophyte produces spores that germinate into a new gametophyte.

4. Mention the ploidy of the following: Answer:

• Protonemal cell of a moss: Haploid (n)
• Primary endosperm nucleus in dicot: Triploid (3n)
• Leaf cell of a moss: Haploid (n)
• Prothallus cell of a fern: Haploid (n)
• Gemma cell in Marchantia: Haploid (n)
• Meristem cell of monocot: Diploid (2n)
• Ovum of a liverwort: Haploid (n)
• Zygote of a fern: Diploid (2n)

5. Write a note on economic importance of algae and gymnosperms. Answer:

• Algae: Food supplement (Chlorella), agar production, hydrocolloids (algin, carrageen), and primary producers in aquatic food chains.
• Gymnosperms: Source of timber, wood pulp (for paper), resins, turpentine, and some edible seeds (Pinus gerardiana).

6. Both gymnosperms and angiosperms bear seeds, then why are they classified separately? Answer: They are classified separately because in gymnosperms, the ovules/seeds are naked (not enclosed by an ovary wall), while in angiosperms, the ovules are enclosed within an ovary, and the seeds develop inside fruits.

7. What is heterospory? Briefly comment on its significance. Give two examples. Answer: Heterospory is the production of two distinct types of spores (microspores and megaspores). Significance: It leads to the differentiation of male and female gametophytes and is considered a precursor to the seed habit. Examples: Selaginella, Salvinia.

8. Explain briefly the following terms: Answer:

• Protonema: The first stage of the moss gametophyte, which is filamentous and green.
• Antheridium: The multicellular male sex organ in bryophytes and pteridophytes.
• Archegonium: The flask-shaped multicellular female sex organ.
• Isogamy: Fusion of two gametes that are similar in size.
• Diplontic: Life cycle where the diploid phase is dominant (e.g., gymnosperms, angiosperms).
• Sporophyll: A leaf that bears sporangia.

9. Differentiate between red algae and brown algae. Answer: Red algae possess r-phycoerythrin and store floridean starch. Brown algae possess fucoxanthin and store laminarin/mannitol. Red algae typically lack flagellated stages.

10. Match the following: Answer: (a) Chlamydomonas - (iii) Algae (b) Cycas - (iv) Gymnosperm (c) Selaginella - (ii) Pteridophyte (d) Sphagnum - (i) Moss

11. Describe the important characteristics of gymnosperms. Answer: Naked-seeded plants, heterosporous (cones), dominant sporophyte, roots with mycorrhiza or coralloid roots, well-adapted leaves (needle-like in conifers, thick cuticle, sunken stomata).

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Answer Key for MCQs

1. c 2. c 3. c 4. b 5. b 6. b 7. b 8. d 9. b 10. b