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#	Question	Answer
1	Which groups are discussed under Kingdom Plantae in this chapter?	Algae, Bryophytes, Pteridophytes, Gymnosperms, and Angiosperms.
2	Why are cyanobacteria no longer considered algae?	Because Monera and Protista members with cell walls have been excluded from Plantae.
3	On what basis did the earliest systems of plant classification work?	Gross superficial morphological characters such as habit, colour, number, and shape of leaves.
4	Which classification system was mainly based on vegetative characters or androecium structure?	The artificial classification system, including the system given by Linnaeus.
5	Why were artificial systems of classification considered unsatisfactory?	They separated closely related species and gave equal weightage to vegetative and sexual characters.
6	Why are vegetative characters considered less reliable in classification?	Because they are more easily affected by the environment.
7	What are natural classification systems based on?	Natural affinities among organisms.
8	Which scientists proposed a natural classification system for flowering plants?	George Bentham and Joseph Dalton Hooker.
9	What is the basis of phylogenetic classification systems?	Evolutionary relationships among organisms.
10	What assumption is made in phylogenetic classification?	Organisms belonging to the same taxa have a common ancestor.
11	What is Numerical Taxonomy based on?	All observable characteristics processed using computers.
12	What is Cytotaxonomy based on?	Cytological information such as chromosome number, structure, and behaviour.
13	What does Chemotaxonomy use for classification?	Chemical constituents of plants.
14	Define algae according to NCERT.	Algae are chlorophyll-bearing, simple, thalloid, autotrophic, and largely aquatic organisms.
15	Name some habitats where algae are found.	Fresh water, marine water, moist stones, soils, wood, and in association with fungi or animals.
16	How do algae reproduce vegetatively?	By fragmentation.
17	What are zoospores?	Flagellated motile spores involved in asexual reproduction of algae.
18	What is anisogamy?	Fusion of two gametes dissimilar in size, as in species of Eudorina.
19	What is oogamy?	Fusion between a large non-motile female gamete and a smaller motile male gamete.
20	Give examples of oogamous algae.	Volvox and Fucus.
21	What proportion of total carbon dioxide fixation on Earth is carried out by algae?	At least half of the total carbon dioxide fixation on Earth is carried out by algae.
22	How do algae help aquatic environments?	They increase the level of dissolved oxygen in their immediate environment.
23	Why are algae considered important primary producers?	They form the basis of the food cycles of all aquatic animals by producing energy-rich compounds.
24	Name some marine algae used as food.	Porphyra, Laminaria, and Sargassum.
25	What are hydrocolloids?	Water-holding substances produced by certain marine brown and red algae.
26	Which algae produce algin and carrageen?	Brown algae produce algin, while red algae produce carrageen.
27	From which algae are agar obtained?	Gelidium and Gracilaria.
28	What are the uses of agar?	Agar is used to grow microbes and in the preparation of ice-creams and jellies.
29	Which unicellular alga is used as a food supplement by space travellers?	Chlorella.
30	What are members of Chlorophyceae commonly called?	Green algae.
31	What forms can the plant body of Chlorophyceae have?	Unicellular, colonial, or filamentous.
32	Which pigments dominate in green algae?	Chlorophyll a and chlorophyll b.
33	Why are green algae usually grass green in colour?	Due to the dominance of chlorophyll a and b pigments.
34	Name the different shapes of chloroplasts in Chlorophyceae.	Discoid, plate-like, reticulate, cup-shaped, spiral, and ribbon-shaped.
35	What are pyrenoids?	Storage bodies located in chloroplasts that contain protein besides starch.
36	What is the cell wall composition of green algae?	An inner layer of cellulose and an outer layer of pectose.
37	How does vegetative reproduction occur in green algae?	By fragmentation.
38	How does asexual reproduction occur in green algae?	By flagellated zoospores produced in zoosporangia.
39	What types of sexual reproduction occur in green algae?	Isogamous, anisogamous, and oogamous.
40	Name some common green algae.	Chlamydomonas, Volvox, Ulothrix, Spirogyra, and Chara.
41	Where are Phaeophyceae mainly found?	Primarily in marine habitats.
42	Which pigments are present in brown algae?	Chlorophyll a, chlorophyll c, carotenoids, and xanthophylls.
43	Which pigment gives brown algae their characteristic colour?	Fucoxanthin.
44	In brown algae, food is stored in which forms?	Laminarin or mannitol.
45	What is the nature of the cell wall in brown algae?	A cellulosic wall covered externally by a gelatinous coating of algin.
46	What structures are present inside the protoplast of brown algae?	Plastids, a centrally located vacuole, and nucleus.
47	By which structure is the plant body of brown algae attached to the substratum?	Holdfast.
48	Name the three main parts of the brown algal body.	Holdfast, stipe, and frond.
49	What is the function of the frond in brown algae?	It acts as a leaf-like photosynthetic organ.
50	How does vegetative reproduction occur in brown algae?	By fragmentation.
51	Describe the zoospores of brown algae.	They are biflagellate, pear-shaped, and possess two unequal laterally attached flagella.
52	What types of sexual reproduction occur in brown algae?	Isogamous, anisogamous, or oogamous.
53	What is the shape of gametes in brown algae?	Pyriform (pear-shaped).
54	Name common examples of brown algae.	Ectocarpus, Dictyota, Laminaria, Sargassum, and Fucus.
55	Why are Rhodophyceae called red algae?	Due to the predominance of the red pigment r-phycoerythrin.
56	Where are most red algae found?	In marine habitats, especially warmer regions.
57	At what depths can red algae occur?	Both near the water surface and at great ocean depths where little light penetrates.
58	What is stored food in red algae?	Floridean starch.
59	Floridean starch is structurally similar to which compounds?	Amylopectin and glycogen.
60	How do red algae reproduce vegetatively?	By fragmentation.
61	What type of spores are produced asexually in red algae?	Non-motile spores.
62	What type of sexual reproduction occurs in red algae?	Oogamous reproduction with complex post-fertilisation development.
63	Name common examples of red algae.	Polysiphonia, Porphyra, Gracilaria, and Gelidium.
64	Which pigments are present in Chlorophyceae?	Chlorophyll a and chlorophyll b.
65	Which pigments are present in Phaeophyceae?	Chlorophyll a, chlorophyll c, and fucoxanthin.
66	Which pigment is characteristic of Rhodophyceae?	Phycoerythrin.
67	What are bryophytes?	Mosses and liverworts commonly found in moist shaded areas in hills.
68	Why are bryophytes called the amphibians of the plant kingdom?	Because they can live on soil but depend on water for sexual reproduction.
69	In which habitats are bryophytes commonly found?	Damp, humid, and shaded localities.
70	What ecological role do bryophytes play in plant succession?	They help in plant succession on bare rocks and soil.
71	How is the plant body of bryophytes differentiated?	It is thallus-like, prostrate or erect, and attached by rhizoids.
72	Do bryophytes possess true roots, stems, and leaves?	No, they lack true roots, stems, and leaves.
73	What is the dominant plant body in bryophytes?	The haploid gametophyte.
74	What is the male sex organ in bryophytes called?	Antheridium.
75	What type of male gametes are produced in bryophytes?	Biflagellate antherozoids.
76	What is the female sex organ in bryophytes called?	Archegonium.
77	Describe the archegonium in bryophytes.	It is flask-shaped and produces a single egg.
78	Why is water essential for fertilisation in bryophytes?	Because antherozoids are released into water to reach the archegonium.
79	What is formed after fusion of antherozoid and egg in bryophytes?	Zygote.
80	What develops from the zygote in bryophytes?	A multicellular sporophyte.
81	Is the bryophyte sporophyte free-living?	No, it remains attached to and dependent on the gametophyte.
82	What is produced after meiosis in bryophyte sporophytes?	Haploid spores.
83	What do bryophyte spores germinate into?	Gametophytes.
84	Which moss provides peat used as fuel and packing material?	Sphagnum.
85	Why are mosses ecologically important?	They colonise rocks, help soil formation, and prevent soil erosion.
86	Into which two groups are bryophytes divided?	Liverworts and mosses.
87	In which habitats do liverworts usually grow?	Moist shady habitats such as marshy grounds, damp soil, bark of trees, and woods.
88	Give an example of a liverwort.	Marchantia.
89	What are gemmae in liverworts?	Green, multicellular, asexual buds.
90	Where are gemmae produced in liverworts?	In gemma cups located on the thalli.
91	How do gemmae help in reproduction?	They detach from the parent body and germinate into new individuals.
92	What are the two stages of the moss gametophyte?	Protonema stage and leafy stage.
93	What is protonema?	A creeping, green, branched, filamentous stage developing directly from a spore.
94	How does the leafy stage develop in mosses?	From the secondary protonema as a lateral bud.
95	How are mosses attached to the soil?	Through multicellular and branched rhizoids.
96	Name common examples of mosses.	Funaria, Polytrichum, and Sphagnum.
97	Which plants are included under pteridophytes?	Horsetails and ferns.
98	In which habitats are pteridophytes commonly found?	Cool, damp, shady places.
99	What is the dominant phase in the life cycle of pteridophytes?	The sporophyte.
100	Into which structures is the pteridophyte sporophyte differentiated?	True root, stem, and leaves.
101	Which vascular tissues are present in pteridophytes?	Xylem and phloem.
102	What are microphylls? Give an example.	Small leaves found in pteridophytes, as in Selaginella.
103	What are macrophylls? Give an example.	Large leaves found in ferns.
104	What are sporophylls?	Leaf-like appendages that subtend sporangia.
105	What are strobili or cones in pteridophytes?	Compact structures formed by sporophylls in plants like Selaginella and Equisetum.
106	How are spores produced in pteridophytes?	By meiosis in spore mother cells within sporangia.
107	What is a prothallus?	An inconspicuous, small, multicellular, free-living, mostly photosynthetic thalloid gametophyte.
108	Why is the distribution of pteridophytes restricted?	Because their gametophytes require cool, damp, shady places and water for fertilisation.
109	Which sex organs are present on pteridophyte gametophytes?	Antheridia and archegonia.
110	Why is water necessary in pteridophyte fertilisation?	For transfer of antherozoids from antheridia to archegonium.
111	What develops from the zygote in pteridophytes?	A multicellular, well-differentiated sporophyte.
112	What are homosporous pteridophytes?	Pteridophytes producing only one kind of spores.
113	Give examples of heterosporous pteridophytes.	Selaginella and Salvinia.
114	What do megaspores and microspores develop into?	Female and male gametophytes, respectively.
115	Why is heterospory considered evolutionarily important?	It is a precursor to seed habit.
116	Name the four classes of pteridophytes.	Psilopsida, Lycopsida, Sphenopsida, and Pteropsida.
117	Give examples of Lycopsida.	Selaginella and Lycopodium.
118	Give examples of Pteropsida.	Dryopteris, Pteris, and Adiantum.
119	Why are gymnosperms called naked-seeded plants?	Because their ovules and seeds are not enclosed by an ovary wall.
120	What type of plants are gymnosperms generally?	Medium-sized trees, tall trees, or shrubs.
121	Name one of the tallest gymnosperm trees.	Sequoia (giant redwood tree).
122	What type of root system is generally found in gymnosperms?	Tap root system.
123	What is mycorrhiza? Give an example from gymnosperms.	Fungal association with roots, seen in Pinus.
124	What are coralloid roots?	Specialised roots associated with nitrogen-fixing cyanobacteria in Cycas.
125	How are conifer leaves adapted to reduce water loss?	They are needle-like with thick cuticle and sunken stomata.
126	Are gymnosperms homosporous or heterosporous?	Gymnosperms are heterosporous.
127	Which two types of spores are produced by gymnosperms?	Haploid microspores and megaspores.
128	Where are microspores and megaspores produced in gymnosperms?	Within sporangia borne on sporophylls.
129	What are strobili or cones?	Structures formed by spirally arranged sporophylls on an axis.
130	What are microsporangiate strobili?	Male cones bearing microsporophylls and microsporangia.
131	What is a pollen grain in gymnosperms?	A highly reduced male gametophyte confined to a limited number of cells.
132	Where does pollen grain development occur?	Within the microsporangia.
133	What are macrosporangiate strobili?	Female cones bearing megasporophylls with ovules or megasporangia.
134	In which gymnosperm are male and female cones borne on the same tree?	Pinus.
135	In which gymnosperm are male cones and megasporophylls borne on different trees?	Cycas.
136	From where is the megaspore mother cell differentiated?	From one of the cells of the nucellus.
137	What is nucellus?	Tissue protected by envelopes forming part of the ovule.
138	What is an ovule in gymnosperms?	The composite structure formed by nucellus and protective envelopes.
139	How many megaspores are formed after meiosis of the megaspore mother cell?	Four megaspores.
140	What develops from one megaspore in gymnosperms?	A multicellular female gametophyte.
141	What female sex organs are present in the female gametophyte of gymnosperms?	A multicellular female gametophyte bearing two or more archegonia.
142	Do gymnosperm gametophytes have an independent free-living existence?	No, they remain within the sporangia retained on the sporophytes.
143	How are pollen grains transferred in gymnosperms?	By air currents.
144	What is the function of the pollen tube in gymnosperms?	It carries male gametes towards the archegonia in the ovule.
145	What develops from the zygote in gymnosperms?	An embryo.
146	Why are gymnosperm seeds called naked seeds?	Because the seeds are not covered.
147	How are angiosperms different from gymnosperms regarding ovules?	In angiosperms, ovules are enclosed within flowers, unlike naked ovules in gymnosperms.
148	In which specialised structures are pollen grains and ovules developed in angiosperms?	Flowers.
149	Where are seeds enclosed in angiosperms?	Inside fruits.
150	What is the size range of angiosperms mentioned in the text?	From Wolffia (smallest) to Eucalyptus trees over 100 metres tall.
151	Mention some economic uses of angiosperms.	They provide food, fodder, fuel, medicines, and commercially important products.
152	Into which two classes are angiosperms divided?	Dicotyledons and monocotyledons.
153	Which groups are included in the plant kingdom?	Algae, bryophytes, pteridophytes, gymnosperms, and angiosperms.
154	How are algae described in the summary?	Chlorophyll-bearing, simple, thalloid, autotrophic, and largely aquatic organisms.
155	On what basis are algae classified into three classes?	Type of pigment possessed and type of stored food.
156	Name the three classes of algae.	Chlorophyceae, Phaeophyceae, and Rhodophyceae.
157	How do algae reproduce vegetatively?	By fragmentation.
158	What are the three types of sexual reproduction in algae?	Isogamy, anisogamy, and oogamy.
159	Why are bryophytes dependent on water?	For sexual reproduction.
160	By which structures are bryophytes attached to the substratum?	Rhizoids.
161	Into which two groups are bryophytes divided?	Liverworts and mosses.
162	What is the main plant body of a bryophyte called?	Gametophyte.
163	What are the male and female sex organs in bryophytes?	Antheridia and archegonia.
164	What is produced after fertilisation in bryophytes?	A sporophyte.
165	Which phase is dominant in pteridophytes?	Sporophyte phase.
166	Which vascular tissues are present in pteridophytes?	Well-differentiated vascular tissues.
167	What do spores of pteridophytes germinate into?	Gametophytes.
168	Why is water required in pteridophytes?	For transfer of male gametes to archegonium.
169	Why are gymnosperms called naked-seeded plants?	Because their ovules are not enclosed by any ovary wall and seeds remain exposed after fertilisation.
170	Which spores are produced in gymnosperms?	Microspores and megaspores.
171	What are microsporophylls and megasporophylls?	Sporophylls arranged spirally on the axis to form male and female cones respectively.
172	What happens after fertilisation in gymnosperms?	The zygote develops into an embryo and ovules into seeds.
173	Into which two classes are angiosperms divided?	Dicotyledons and monocotyledons.
174	Match: Chlamydomonas belongs to which group?	Algae.
175	Match: Cycas belongs to which group?	Gymnosperm.
176	Match: Selaginella belongs to which group?	Pteridophyte.
177	Match: Sphagnum belongs to which group?	Moss.