Kingdom Plantae
Short Questions
1. Why are plants called producers on land?
Answer: They perform photosynthesis, producing food and oxygen, forming the base of food chains.
2. What is the main difference between Cryptogamae and Phanerogamae?
Answer: Cryptogamae produce spores and lack seeds, while Phanerogamae produce seeds.
3. What is the plant body type in Thallophyta?
Answer: It is thalloid, undifferentiated into roots, stems, or leaves.
4. Name two examples of Chlorophyceae.
Answer: Chlamydomonas and Spirogyra.
5. What is the reserve food in Rhodophyceae?
Answer: Floridean starch.
6. Why are Bryophytes called amphibious plants?
Answer: They require water for fertilization, thriving in moist habitats.
7. What are rhizoids in Bryophytes?
Answer: Root-like structures for absorption and anchorage.
8. Name two examples of Pteridophyta.
Answer: Nephrolepis and Equisetum.
9. What is the dominant phase in Pteridophytes?
Answer: Sporophyte.
10. What are naked seeds in Gymnosperms?
Answer: Seeds not enclosed in a fruit.
11. What is double fertilization in Angiosperms?
Answer: One sperm forms a zygote, another forms endosperm.
12. What type of root system do Dicotyledonae have?
Answer: Tap root system.
13. What is the venation pattern in Monocotyledonae leaves?
Answer: Parallel venation.
14. What is alternation of generations in plants?
Answer: Alternating sporophyte (diploid) and gametophyte (haploid) phases in the life cycle.
15. What is the smallest Angiosperm?
Answer: Wolffia (1 mm in size).
Long Questions
1. Differentiate between Thallophyta and Bryophyta.
Answer: Thallophyta have a thalloid, undifferentiated plant body and are mostly aquatic, lacking vascular tissues. Bryophyta have a thalloid or leafy gametophyte, are terrestrial, and require water for fertilization. Both lack vascular tissues, but Bryophytes have rhizoids for anchorage.
2. Explain the salient features of Chlorophyceae.
Answer: Chlorophyceae, or green algae, are mostly freshwater with unicellular, colonial, or filamentous plant bodies. They contain chlorophyll a and b, store true starch, and have cellulose cell walls. Examples include Chlamydomonas and Spirogyra, with pyrenoids for starch storage.
3. Why are Pteridophytes considered the first vascular plants?
Answer: Pteridophytes are the first plants with true vascular tissues (xylem and phloem) and differentiated roots, stems, and leaves. They are true land plants, unlike non-vascular Thallophyta and Bryophyta. Their vascular system allows efficient water and nutrient transport.
4. Describe the economic importance of Bryophytes.
Answer: Bryophytes like Sphagnum provide peat used as fuel and packing material due to high water-holding capacity. They decompose rocks to form soil, aiding higher plant growth. Dense moss mats prevent soil erosion, acting as soil binders.
5. What are the key differences between Gymnospermae and Angiospermae?
Answer: Gymnosperms have naked seeds and lack vessels in xylem, while Angiosperms have enclosed seeds within fruits and vessels in xylem. Gymnosperms undergo single fertilization, whereas Angiosperms exhibit double fertilization. Examples include Cycas (Gymnosperm) and Helianthus (Angiosperm).
6. Explain the structure of the plant body in Phaeophyceae.
Answer: Phaeophyceae, or brown algae, have a plant body differentiated into holdfast, stipe, and frond, mostly marine. Their cell walls contain cellulose, fucans, and algin, with pigments like chlorophyll a, c, and fucoxanthin. Examples include Sargassum and Laminaria.
7. How do Dicotyledonae and Monocotyledonae differ in their vascular bundles?
Answer: Dicotyledonae have conjoint, collateral, and open vascular bundles with cambium, allowing secondary growth. Monocotyledonae have conjoint, collateral, and closed vascular bundles without cambium, lacking secondary growth. This affects their ability to increase girth over time.
8. What is the significance of alternation of generations in plants?
Answer: Alternation of generations involves alternating diploid sporophyte and haploid gametophyte phases in a plant’s life cycle. The sporophyte produces spores via meiosis, which develop into gametophytes that produce gametes. This cycle ensures genetic diversity and adaptation, seen in Bryophytes and Pteridophytes.
9. Describe the reproductive features of Rhodophyceae.
Answer: Rhodophyceae, or red algae, reproduce via spores and gametes, with a thalloid plant body in marine or freshwater habitats. They contain chlorophyll a, d, and phycoerythrin, storing Floridean starch. Examples like Gelidium produce agar-agar, used in tissue culture.
10. Why do Monocots lack secondary growth, unlike Dicots?
Answer: Monocots have closed vascular bundles without cambium, preventing the formation of additional xylem and phloem. Dicots have open vascular bundles with cambium, enabling secondary growth and increased girth. This is why monocots like maize do not thicken over time.
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