80 Questions with Answers and Explanations on “Plant Kingdom” for Botany Students.
1. Sexual reproduction involving fusion of two cells in Chlamydomonas is
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(a) isogamy
(b) homogamy
(c) somatogamy
(d) hologamy.
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Answer and Explanation:
1. (d): Isogamy involves the fusion of gametes which are morphologically and physiologically similar. They are called isogametes. In Chlamydomonas, two vegetative cells may fuse to form a zygospore and the phenomenon is called as hologamy. As a result of fusion of two gametes, zygospore is formed.
2. Prothallus (gametophyte) gives rise to fern plant (sporophyte) without fertilization. It is
(a) apospory
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(b) apogamy
(c) parthenocarpy
(d) parthenogenesis.
Answer and Explanation:
2. (b): Prothallus (gametophyte) gives rise to fern plant (sporophyte) without fertilization. This phenomenon is called apogamy. Development of sporophyte from gametophyte without forming gamete is apogamy. Such sporophyte is haploid in nature.
3. In P/rtHs/Cyccw/gymnosperms, the endosperm is
(a) triploid
(b) haploid
(c) diploid
(d) tetraploid.
Answer and Explanation:
3. (b): In Pmz/.v/Cyca.v/gymnosperms the endosperm is haploid because it is produced before fertilization.
4. Evolutionary important character of Selaginella is
(a) heterosporous nature
(b) rhizophore
(c) strobili
(d) ligule.
Answer and Explanation:
4. (a): Evolutionary important character of Selaginella is heterosporous nature. Selaginella produces two types of spores microspores and megaspores. Heterospory in the life cycle of Selaginella leads to the formation of seed habit.
5. Sperms of both Funaria and Pteris were released together near the archegonia of Pteris. Only its sperms enter the archegonia as
(a) Pteris archegonia repel Funaria sperms
(b) Funaria sperms get killed by Pteris sperms
(c) Funaria sperms are less mobile
(d) Pteris archegonia release chemical to attract its sperms.
Answer and Explanation:
5. (d): Sperms of both Funaria and Pteris were released together near the archegonia. But only the sperms of Pteris enter the archegonia, as Pteris archegonia releases a chemical malic acid to attract its sperms for fertilization.
6. In F/Vws/gymnosperms, the haploid structures are
(a) megaspore, endosperm and embryo
(b) megaspore, pollen grain and endosperm
(c) megaspore, integument and root
(d) pollen grain, leaf and root.
Answer and Explanation:
6. (b): In Pinus gymnosperms, endosperm is produced before fertilization and hence it is haploid. Megaspore and pollen grains are structures of male gametophytes and it is also haploid.
7. Apophysis in the capsule of Funaria is
(a) lower part
(b) upper Part
(c) middle part
(d) fertile part.
Answer and Explanation:
7. (a): Apophysis is basal portion of capsule in continuation with seta. The outer layer of apophysis is epidermis which has stomata for gaseous exchange. In capsule of Funaria stomata are present only in apophysis.
8. Moss peristome takes part in
(a) spore dispersal
(b) photosynthesis
(c) protection
(d) absorption.
Answer and Explanation:
8. (a): Moss peristome is present in capsule and takes part in spore dispersal. The hygroscopic action of peristomial teeth help in the removal of operculum. The lengthening and shortening of peristomial teeth help in the dispersal of spores. The inner peristome acts as a sieve allowing only a few spores to escape at a time.
9. Protonema occurs in the life cycle of
(a) Riccia
(b) Funaria
(c) Anthoceros
(d) Spirogya.
Answer and Explanation:
9. (b): Protonema occurs in the life cycle of Funaria. The spore is the first cell of gametophytic generation and it germinates to form a filamentous branched alga like structure called protonema. If gives rise to new plant.
10. The product of conjugation in Spirogyra or fertilization of Chlamydomonas is
(a) zygospore
(b) zoospore
(c) oospore
(d) carpospore.
Answer and Explanation:
10. (a): The product of conjugation in Spirogyra or fertilization of Chlamydomonas is zygospore. Both are the members of green algae where gametes are fused to form zygote which develops into a thick walled zygospore.
11. The common mode of sexual reproduction in Chlamydomonas is
(a) isogamous
(b) anisogamous
(c) oogamous
(d) hologamous.
Answer and Explanation:
11. (a): In Chlamysomonas sexual reproduction takes place through isogamy, anisogamy, and oogamy, lsogamy is the fusion of similar gametes. Anisogamy is fusion of morphologically similar but physiologically different cells. Oogamy is fusion of different gametes.
12. Which one has the largest gametpophyte?
(a) Cycas
(b) angiosperm
(c) Selaginella
(d) moos
Answer and Explanation:
12. (d): Moss has the largest gametophyte. Mosses are small, soft plants that are typically 1-10 cm tall, some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds and their simple leaves cover the thin wiry stem.
13. Bryophytes are amphibians because
(a) they require a layer of water for carrying out sexual reproduction
(b) they occur in damp places
(c) they are mostly aquatic
(d) all the above.
Answer and Explanation:
13. (a): Bryophytes are called the amphibians because they require a layer of water for carrying out sexual reproduction. They grow in the moist places on land but they require water during the time of fertilization i.e. for completion of life cycle.
14. A plant in which sporophytic generation is represented by zygote is
(a) Pinus
(b) Selaginella
(c) Chlamydomonas
(d) Dryopteris.
Answer and Explanation:
14. (c): A plant in which sporophytic generation is represented by zygote is Chlamydomonas. It is a type of algae that has gametophytic plant body (haploid). It reproduces sexually by gametes which are isogametes that fuse to produce diploid zygote which is the only sporophytic generation.
15. The plant group that produces spores and embryo but lacks vascular tissues and seeds is
(a) pteridophyta
(b) rhodophyta
(c) bryophyta
(d) phaeophyta.
Answer and Explanation:
15. (c): Bryophytes are the plants which produces spores and embryos but they do not have vascular tissue system. While rhodophytes and phaeophytes are algae and produces spores (no embryos) only and pteridophytes produces spores, embryo and well developed vascular tissue system.
16. Which one of the following is not common between Funaria and Selaginella?
(a) archegonium
(b) embryo
(c) flagellate sperms
(d) roots.
Answer and Explanation:
16. (d): Root is not common between Funaria and Selaginella. Funaria is a bryophyte and have archegonium, embryo, flagellated sperms which are also present in Selaginella. Selaginella is a pteridophyte and it has root which is absent in Funaria.
17.
A plant having seeds but lacking flowers and fruits belongs to
(a) pteridophytes
(b) mosses
(c) ferns
(d) gymnosperms.
Answer and Explanation:
17. (d): A plant having seed but lacking flowers and fruit belongs to gymnosperms. Gymnosperms are vascular land plants and bears seeds which are naked i.e., ovules not enclosed in the ovary. Hence, flowers are absent.
18. In Pinus, the pollen grain has 6 chromosomes then in its endosperm will have
(a) 12
(b) 18
(c) 6
(d) 24
Answer and Explanation:
18. (c): In Pinus, if the pollen grain has 6 chromosomes then in its endosperm will also have 6 chromosomes as endosperm and pollen grains are both haploid structures.
19. Resin and turpentine are obtained from
(a) Cycas
(b) Pinus
(c) Cedrus
(d) Abies.
Answer and Explanation:
19. (b): Resins and turpentine is obtained from Pinus which is gymnospermic plant. Cycas is a ornamental plant. Paper and Canada balsam is obtained from Abies and timber is obtained from Cedrus deodara.
20. Turpentine is got from
(a) angiospermous wood
(b) bryophytes
(c) gymnospermous wood
(d) ferns.
Answer and Explanation:
20. (c): Turpentine is commercially very important. It is obtained from Pinus which is a member of gymnosperm. It is obtained from Abies balsamea.
21. Pteridophytes differ from mosses/bryophytes in possessing
(a) independent gametophyte
(b) well developed vascular system
(c) archegonia
(d) flagellate spermatozoids.
Answer and Explanation:
21. (b): Pteridophytes differ from mosses/bryophytes in having well developed vascular tissue system. In mosses/ bryophytes vascular tissue is absent.
22. In Ulothrix/Spirogyra, reduction division (meiosis) occurs at the time of
(a) gamete formation
(b) zoospore formation
(c) zygospore germination
(d) vegetative reproduction.
Answer and Explanation:
22. (c): In UlothrixISpirogyra reduction division (meiosis) occurs at the time of zygospore formation. Plant body of Ulothrix and Spirogyra, is gametophytic (haploid), they produce zoogametes (n) which fuses to form zygosporic (2n) diploid, which is a resting spore. Onset of favourable condition zygospore undergoes reductional division, or meiosis to produce zoo- meiospores.
23. Chloroplast of Chlamydomonas is
(a) stellate
(b) cup-shaped
(c) collar-shaped
(d) spiral.
23. (b): Chloroplast in Chlamydomonas is cup-shaped. It is one celled structure. Whereas stellate, spiral and collar shaped chloroplasts are present in Zygnema, Spirogyra and Ulothrix respectively.
24. Pteridophytes differ from bryophytes and thallophytes in having
(a) vascular tissues
(b) motile antherozoids
(c) archegonia
(d) alternation of generations.
Answer and Explanation:
24. (a): Pteridophytes differs from bryophytes and thallophytes in having well developed vascular tissue system. Vascular tissue plays an important role in conducting water and food materials to the plants. Whereas these are absent in bryophytes and thallophytes.
25. Pyrenoids are the centres for formation of
(a) Porphyra
(b) enzymes
(c) fat
(d) starch.
Answer and Explanation:
25. (d): Pyrenoids are the centres for formation of starch. There are present in chloroplast and are proteinaceous in nature covered by starch plate. They synthesizes and store starch in them.
26. Pinus differs from mango in having
(a) tree habit
(b) green leaves
(c) ovules not enclosed in ovary
(d) wood.
Answer and Explanation:
26. (c): Pinus is a gymnospermic plants which hive a well developed conducting tissue system but seeds are naked. Whereas mango is a angiospermic plants in which seed are enclosed in the ovary and fruit is present.
27. Which one is the most advanced from evolutionary view point?
(a) Selaginella
(b) Funaria
(c) Chlamydomonas
(d) Pinus.
Answer and Explanation:
27. (d): Pinus is more advanced from the evolutionary point of view. It is a gymnosperms (of phanerogams) having well developed vascular conducting system and bears seeds. While others Selaginella, Funaria and Chlamydomonas do not bear seeds.
28. In bryophytes
(a) both generations are independent
(b) gametophytes are dependent upon sporophytes
(c) sporophytes complete their life cycle
(d) sporophytes are dependent upon gametophytes.
Answer and Explanation:
28. (d): In Bryophytes the main body is gametophytic (n) which is independent and may be thallose (no differentiation in root, stem and leaves). It bears sex organs and after fertilization the sporophytic phase starts. The sporophyte is organically attached to the gametophytic plant and is nutritionally dependent on the gametophyte. It may be wholly or partially dependent on the gametophyte.
29. In Pinus, the wings of the seed develops from
(a) ovuliferous scale
(b) integument
(c) nucellus
(d) bract.
Answer and Explanation:
29. (a): Mature ovule with embryo constitutes seed. The seed is covered with hard seed coat. The outer layer of the seed coat is testa (from middle stony layer). Testa encloses a brown, thin membranous tegmen (from inner fleshy layer). The tegmen surrounds fleshy endosperm. Inside endosperm is present the embryo. At maturity of seed, a thin layer of ovuliferous scale fuses with testa to form a wing (i.e., seeds are winged) which helps in the dispersal of seed.
30. In chlorophyceae, the mode of sexual reproduction is
(a) isogamy
(b) anisogamy
(c) oogamy
(d) all of these.
Answer and Explanation:
30. (d): The class chlorophyceae is characterised by the members possessing grass-green chromatophores. The other distinguishing features of the class are the presence of starch-as reserve food material, pyrenoids – commonly surrounded by starch sheaths, motile cells bearing anterior flagella of equal length, etc.
In chlorophyceae, three types of sexual reproduction takes place namely isogamy, anisogamy and oogamy. Isogamous type : Here the fusing gametes are morphologically similar but physiologically distinct e.g., Chlamydomonas debaryanum and Ulothrix. Anisogamous type: Fusion takes place between morphologically and physiologically distinct gametes (anisogametes). Chlamydomonas braunii and Pandorina. Oogamous type: Most advanced type in which fusion of small biciliate or multiciliate, active male gamete with large, passive female gamete, Oedogonium, Chlamydomonas coccifera.
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31. Many blue-green algae occur in thermal springs (hot water springs). The temperature tolerance of these algae have been attributed to their
(a) mitochondrial structure
(b) importance of homopolar bonds in their proteins
(c) cell wall structure
(d) modern cell organization.
Answer and Explanation:
31. (c): Some algae withstand or tolerate a very high temperature and these are often called thermal algae. Such forms are known to grow upto 85CC, nearly boiling water. Their cell wall is hard and protective. A typical cell wall of algae consists of two nonliving layers.
The inner layer is firm consisting of microfibrils and outer layer is gelatinous and amorphous. Various polysaccharides such as cellulose, pectin, mucilage constitute the typical cell wall. The mucilage covering of the cell is thick and dense and is called the sheath. This sheath holds the cells in colonies together, is having water absorbing and water retaining capacity. It thus protects them under dessicating conditions. Thus they are able to survive under high temperature.
32. A well developed archegonium with neck consisting of 4-6 rows and neck canal cells, characterises
(a) gymnosperms and flowering plants
(b) pteridophytes and gymnosperms
(c) gymnosperms only
(d) bryophytes and pteridophytes.
Answer and Explanation:
32. (d): Bryophytes and pteridophytes both have alternation of generation. The gametophytic phase is dominant in bryophytes whereas in pteridophytes it is short lived. Sex organs are embedded is some members of bryophytes and pteridophytes. Sperms are flagellate and so water is required for fertilization. Sterile jacket is present around the sex organs for protection. Archegonium appeared for the first time in bryophytes in plant kingdom.
It is a flask shaped structure. It has swollen basal portion called venter and upper elongated neck. The venter has egg cell and venter canal cell. There are 4-6 vertical rows of neck cells enclosing neck canal cells in bryophytes. The archegonia have short neck made of four rows of vertically elongated cells that encloses four neck canal cells in pteridophytes.
33. The sexual reproduction is absent in
(a) Spirogyra
(b) Nostoc
(c) Ulothrix
(d) Volvox.
Answer and Explanation:
33. (b): Nostoc belongs to cyanophyceae. In this entire class sexual reproduction is completely absent. It reproduces by colony formation, hormogonia, akinetes, heterocysts and endospres. However genetic recombination has been observed. It may be probably through transformation or conjugation.
The other three algae- Spirogyra, Ulothrix and Volvox belong to chlorophyceae. The members of this class show isogamous, anisogamous and oogamous type of sexual reproduction.
34. The plant body of moss (Funaria) is
(a) completely sporophyte
(b) predominantly gametophyte with sporophyte
(c) completely gametophyte
(d) predominantly sporophyte with gametophyte.
Answer and Explanation:
34. (b): Funaria is known as common moss or green moss. The plant body is foliose that consists of stem axis which bears many leaves and instead of roots, rhizoids are present. It is gametophytic (n) and independent.
It bears antheridia and archegonia on the same plant but on different branches.
After fertilization the zygote (2n) divides to form the sporophyte which consists of foot, seta and capsule. The basal foot is embedded in the apex of female branch. It absorbs nutrients and provides support for the sporophyte. Inside the capsule haploid spores are produced as a result of meiosis. Thus again the gametophytic phase starts. So the gametophytic phase is the dominant phase of the life cycle of Funaria.
35. The pyrenoids are made up of
(a) proteinaceous centre and starchy sheath
(b) core of nucleic acid surrounded by protein sheath
(c) core of protein surrounded by fatty sheath
(d) core of starch surrounded by sheath of protein.
Answer and Explanation:
35. (a): Pyrenoids are found in many bryophytes and algae. They are small, spherical bodies found in the cytoplasm of a plant cell. They are rich in proteins and are surrounded by a starch sheath.
36. A gymnospermic leaf carries 16 chromosomes. The number of chromosomes in its endosperm will be
(a) 12
(b) 8
(c) 16
(d) 24
Answer and Explanation:
36. (b): Gymnosperms show distinct alternation of generations. The sporophytic phase is dominant. The sporphyte is differentiated into root, stem and leaves. So the number of chromosomes in a leaf cell is diploid (2n), (2n = 16). Double fertilization is absent in gymnosperms. The endosperm develops before fertilization directly from the megaspore. So the number of chromosomes in endosperm will be 8(n = 8).
37. Elater mechanism for spore dispersal is exhibited by
(a) Liverworts
(b) Marchantia
(c) Riccia
(d) Funaria.
Answer and Explanation:
37. (b): Marchanlia is a liverwort in which the sex organs are borne on disc shaped 8-Iobed receptacles borne at the tip of vertical gametophores. Sperms are attracted to opened archegonia by proteins and K+ salts. Fertilization produces a parasitic sporophyte made of foot, seta and capsule. The capsule encloses sporocytes and elaters. These elaters show twisting movements due to spiral bands of thickenings and this leads to liberation and dispersal of spores. In Riccia elaters are absent and in Funaria peristome teeth help in spore dispersal.
38. Which of the following plant kingdom is called ‘amphibians’?
(a) pteridophyta
(b) thallophyta
(c) tracheophyta
(d) bryophyta.
Answer and Explanation:
38. (d): Bryophytes are land inhabiting or terrestrial plants. They complete their vegetative phase on land but water is necessary for their reproductive phase i.e. for completion of life cycle. So bryophytes are known as amphibians of plant kingdom.
Thallophytes have a plant body that is not clearly differentiated into root, stem and leaves. They do not have vascular tissues and so are always aquatic. Pteridophytes are most primitive vascular plants. They have developed vascular tissues and so they were the first vascular plants on land.
Tracheophyte includes all vascular plants – pteridophytes, gymnosperms and angiosperms.
39. The smallest plant family ‘Gymnosperm’ has how many species?
(a) 640
(b) 300
(c) 1000
(d) 900
Answer and Explanation:
39. (d): Gymnosperms originated about 200 million years ago and were dominant species at that time. However most of the members have become extinct now and only few living forms are known today. There are around 900 living species of this group.
40. Brown algae is characterised by the presence of
(a) fucotfanthin
(b) haematochrome
(c) phycocyanin
(d) phycoerythrin.
Answer and Explanation:
40. (a): Brown algae are the members of the class phaeophyceae. Their chromatopores are ellipsoidal or discoid. They contain chlorophyll a, chl c, P- and c- carotenes and xanthophyll pigments (e.g., lutein, flavoxanthin, violaxanthin). They also contain large amount of a brown pigment – fucoxanthin which masks the green colour of chlorophyll pigment. This gives characteristic brown colour to these plants, hence the name brown algae.
The non-motile resting spores of Chlamydomonas contain a red pigment called hematochrome. phycocyanin and phycoerythrin are water soluble pigments found in red and blue-green algae.
41. Multicellular branched rhizoids and leafy gametophytes are the characteristics of
(a) some bryophytes
(b) pteridophytes
(c) all bryophytes
(d) gymnosperms.
Answer and Explanation:
41. (a): The division Bryophyta includes three classes Hepaticopsida, Anthocerotopsida and Bryopsida. The members of Hepaticopsida and Anthocerotopsida have a thallose plant body which is dorsiventrally differentiated and dichotomously branched. On the ventral surface unicellular or multicellular rhizoids are present. The member of Bryopsida has a main plant body that has a leafy gametophore made up of an axis having spirally arranged leaves.
The rhizoids are multicellular and branched e.g. Sphagnum, Funaria, Riccia, and Anthoceros. So only few members of bryophytes have leafy gametophytes. Gymnosperms have well developed plant body having root stem and leaves. They do not have rhizoids.
42. Bryophytes can be separated from algae, because they
(a) possess archegonia
(b) contain chloroplast
(c) are thalloid forms
(d) have no conducting tissue.
Answer and Explanation:
42. (a): Bryophytes and algae are both autotrophic, plant body thallus like and devoid of vascular tissues. Instead of roots, rhizoids are present for attachment and absorption purpose. Both algae and bryophytes have motile sperms and need water for fertilization.
But bryophytes can be separated from algae because archegonium originated for the first time in bryophytes in plant kingdom. It is a flask shaped structure with swollen base called venter and upper elongated neck. The venter contains a venter canal cell and an egg cell. It is surrounded by one celled thick sterile jacket layer. In algae sex organs are non-jacketed and unicellular.
43. Ulothrix filaments produce
(a) heterogametes
(b) basidiospores
(c) isogametes
(d) anisogametes.
Answer and Explanation:
43. (c): Ulothrix belongs to class chlorophyceae of division Thallophyta. The plant body consists of an unbranched filament, consisting of numerous cylindrical cells joined end to end. It is heterothallic and sexual reproduction is of isogamous type. Except holdfast each cell of the filament can give rise to 64 to 128 gametes. The gametes are similar in size, shape and other features. So these gametes are called isogametes.
When two gametes of (+) and (-) strain come together they fuse and a quadriflagellate zygospore is formed. Anisogametes are morphologically and physiologically distinct gametes produced in Chlamydomonas braunii and Pandorina. Basidiospores are the haploid spores produced by a basidium in basidiomycete’s fungi.
44. An alga, very rich in protein,/is
(a) Chlorella
(b) Nostoc
(c) Spirogyra
(d) Ulothrix.
Answer and Explanation:
44. (a): Chlorella is a unicellular green alga that contains high percentage of proteins, lipids and most of the known vitamins (carotene, riboflavin, vitamin Bl2, choline etc) and grows more quickly than Porphyra, so scientists are doing research to obtain food from it. The nutritional value is comparable to the mixture of soybeans and spinach.
45. Heterospory and seed habit are often exhibited by a plant possessing
(a) petiole
(b) ligule
(c) bract
(d) spathe.
Answer and Explanation:
45. (b): Heterospory means production of two different sizes of spores-megaspore and microspore. All bryophytes are homosporous. Heterospory originated in some pteridophytes like Selaginella. It is commonly called clubmoss or spike moss. Its leaves contain a flaplike outgrowth at the base on the adaxial side called ligule.
The leaves are of two types – megasporophyll bearing megasporangia and microsporophylls bearing microsporangia. The megasporangium contains four large megaspores and the microsporangia contain large number of small microspores. Thus Selaginella is heterosporous. In some species of Selaginella the embryo remains attached to the sporophyte for a long time and it is the habit towards seed habit.
46. Transfusion tissue is present in the leaves of
(a) Pinus
(b) Dryopteris
(c) Cycas
(d) Both (a) and (c).
Answer and Explanation:
46. (d): Transfusion tissue is a specialized tissue present on either side of midrib in between the palisade and spongy tissues of the leaf of Cycas and also in Pinus leaf at the sides of the sclerenchymtous region. It is made of horizontally arranged tracheids. These supply water and minerals to mesophyll tissue upto margins so that the mesophyll cells can carry out photosynthesis. It is of two type’s primary transfusion tissue present next to the midrib bundle and secondary transfusion tissue that runs upto margins of the leaf. In Pinus it consists of tracheids and albuminous cells.
47. The walking fern is so named because
(a) it propagates vegetatively by its leaf tips
(b) it known how to walk by itself
(c) its spores are able to walk
(d) it is dispersed through the agency of walking animals.
Answer and Explanation:
47. (a): Walking fern is named so because when its leaf tips come in contact with soil, form new plants as adventitious buds develop at leaf tips. This helps in the spread of fern over a large soil surface and thus the name ‘walking fern’.
48. Bryophytes are dependent on water, because
(a) water is essential for their vegetative propagation
(b) the sperms can easily reach upto egg in the archegonium
(c) archegonium has to remain filled with water for fertilization
(d) water is essential for fertilization for their homosporous nature.
Answer and Explanation:
48. (b): Bryophytes are called amphibians of plant kingdom because they complete their vegetative phase on land but water is necessary for their reproductive phase. Water helps in maturation and dehiscence of sex organs in bryophytes. It also helps in the transfer of sperms to the archegonia that make water essential for completion of life cycle of bryophytes.
49. Ulothrix can be described as a
(a) filamentous alga lacking flagellated reproductive stages
(b) membranous alga producing zoospores
(c) filamentous alga with flagellated reproductive stages
(d) non-motile colonial alga lacking zoospores.
Answer and Explanation:
49. (c): Ulothrix is a green filamentous alga, belonging to class chlorophyceae. The plant body is an unbranched filament consisting of numerous cylindrical cells joined end and end. Under favourable conditions, each cell produces zoospores except holdfast. These zoospores are of two types – Macrozoospores and microzoospores.
The macrozoospores are larger in size and are quadriflagellate and the microzoospores are smaller zoospores which may be biflagellate or quadrifagelleate. Under unfavourable conditions, nonmotile mitospores called aplanospores are produced. Sexual reproduction in Ulothrix is of isogamous type. The isogamete fuse to form a quadriflagellate zygospore which after meiosis forms 16 aplanospores or zoospores.
50. Largest sperms in the plants world are found in
(a) Banyan
(b) Cycas
(c) Thuja
(d) Pinus.
Answer and Explanation:
50. (b): The male gametes of Cycas are largest (300 ft) in nature, visible to naked eye and are oval in form, broad (top-shaped) and naked at posterior end and spirally coiled in the anterior half with thousands of small cilia.
51. Which one of the following statements about Cycas is incorrect?
(a) it has circinate vernation
(b) its xylem is mainly composed of xylem vessel
(c) its roots contain some blue-green algae
(d) it does not have a well organized female flower.
Answer and Explanation:
51. (b): Cycas belongs to order cycadales of gymnosperms. Its leaves show circinate vernation i.e. the leaves are coiled in young stage. The coralloid roots in Cycas arise from the lateral branches of the normal roots and contain blue-green algae like Nostoc and Anabaena. A well developed flower like that of angiosperms is absent in Cycas. It has compact cones containing microsporophylls and megasporophylls. The megaspores are loosely arranged on the megasporophyll. The male cone is a compac structure. Vessels in xylem are absent and it contains only tracheids for conduction of water.
52. Dichotomous branching is found in
(a) liverworts
(b) pteridophytes
(c) fern
(d) Funaria.
Answer and Explanation:
52. (a): Dichotomous branching is characteristic feature of liverworts e.g. Riccia, Marchantia, Pellia etc.. It is a primitive form of branching. It is also called forked branching. In liverworts thethallus is flat and dorsiventral and dichotomously branched. The thallus has a notch at the anterior end. At the base of the notch, there is a growing point consisting of a single apical cell. It divides repeatedly to form two branches of the same size.
53. Which of the following is true about bryophytes?
(a) they are thalloid
(b) they posses archegonia
(c) they contain chloroplast
(d) all of these.
Answer and Explanation:
53. (d): Bryophytes are green photosynthetic and thalloid structures where the plant body root, stem and leaves. Instead of roots, rhizoids are present for attachment and absorption purpose.
They have motile sperms and so they need water for fertilization. Archegonia evolved for the first time in bryophytes in the plant kingdom. It is a flask shaped structure with swollen base called venter and upper elongated neck. The venter contains a venter canal cell and an egg cell. It is surrounded by one celled thick sterile jacket layer.
54. In which of the following would you place the plants having vascular tissue lacking seeds?
(a) pteridophytes
(b) gymnosperms
(c) algae
(d) bryophytes.
Answer and Explanation:
54. (a): Algae, bryophyte and pteridophyte are cryptogams, but out of them algae, and bryophytes are lower cryptogams and do not possess vascular tissue (xylem and phloem), whereas in pteridophytes, vascular tissue system is well developed and so these are higher cryptogams or vascular cryptogams. The term cryptogam means that these plants reproduce by means of spores and do not produce seeds.
The vascular tissue of pteridophytes is well developed. They contain both xylem and phloem. In xylem, vessels are absent and in phloem companion cells are absent. So pteridophytes or vascular cryptogams are a group of seedless vascular plants that have successfully invaded the land and reproduce by means of spores. Gymnosperms are naked seed bearing plants called phanerogams.
55. Bryophytes comprise
(a) dominant phase of gametophyte which produces spores
(b) small sporophyte phase and generally parasitic on gametophyte
(c) sporophyte is of longer duration
(d) dominant phase of sporophyte which is parasitic.
Answer and Explanation:
55. (b): In bryophytes the main plant body is gametophytic which is independent and may be thallose (no differentiation in root, stem and leaves) e.g., Riccia, Marchantia, Anthoceros etc. or foliose (having leafy axis) e.g. Sphagnum, Funaria etc.
The gametophyte bears the sex organs antheridium and archegonium. Sexual reproduction is of oogamous type. It forms zygote that gives rise to the sporophytic phase. It is differentiated into foot, seta and capsule. The capsule produces spores after meiosis that again gives raise to gametophytic phase. The sporophyte is partially or fully dependent upon the gametophyte and is of shorter duration.
56. The antherozoids of Funaria are
(a) multiciliated
(b) monociliated
(c) aciliated
(d) biciliated.
Answer and Explanation:
56. (d): Androcytes or antherozoid mother cell of Funaria metamorphoses into a single biflagellate spermatozoid (antherozoids). It is a spirally coiled biflagellate (biciliated) structure.
57. Plant group with largest ovule, largest tree, and largest gametes is
(a) gymnosperm
(b) angiosperm
(c) bryophyta
(d) pteridophyta.
Answer and Explanation:
57. (a): Gymnosperms are the most primitive seed plants. The plants are generally perennial, woody trees or shrubs. In general, tallest trees are in gymnosperms e.g. Sequoia sempervirens is 366 ft. in height. The male gametes of Cycas are largest (300) in size; they are visible to naked eye and are oval in form and top-shaped. The ovule of Cycas is also largest in the plant kingdom.
58. In ferns, meiosis takes place at the time of
(a) spore formation
(b) spore germination
(c) gamete formation
(d) antheridia and archegonia formation.
58. (a): A fern plant body is sporophytic (2n) and is differentiated into roots, stems and leaves. On the ventral surface of leaves sporangia are borne in a group called sori. Inside the sporangium are present the spores which are formed by reduction duvsion.
Thus the spores produced are haploid in nature and germinate to produce a prothallus that represents the gametophytic generation. Antheridium and archegonium are borne on this prothallus. Thus meiosis takes place at the stage of spore formation.
59. A student observed an algae with chlorophyll a, b and phycoerythrin, it should belong to
(a) phaeophyta
(b) rhodophyta
(c) chlorophyta
(d) bacillariophyta.
59. (b): The algal class rhodophyceae contains a red pigment (r-phycocrythrin) and a blue pigment (r-phycocynin) in the chromatphores.
These pigments can utilize those wavelengths of light (blue-green region of spectrum, i.e., 480-520 nm) that are not absorbed by chlorophyll. This enables red algae to grow at greater depths than other plants (upto 300 ft. below water). In addition to these, chl.-a, chl,-d, carotenes and xanthophylls are present.
In phaeophyceae chromatophores are yellowish brown in colour possessing xanthophylls in abundance. Bacillariophyceae are called ‘diatoms’ due to presence of an accessory brown pigment called ‘diatomin’, other pigments are chl.-a, chl.-c (but not chl.-b), carotenes and xanthophylls.
In chlorophyceae colouring pigments are just like higher plants, i.e., Chl.-a, Chl.-b, xanthophylls and carotenes.
60. Cycas has two cotyledons but not included in angiosperms because of
(a) naked ovules
(b) seemSTike monocot
(c) circinate ptyxis
(d) compound leaves.
Answer and Explanation:
60. (a): Cycas belongs to order cycadales of gymnosperms because it has naked seed. It is not enclosed inside a fruit. It does not have double fertilization and so the endosperm formed is haploid in nature and not triploid. So it is not included in angiosperms as they have ovules (or seeds) produced inside fruit. This is the main difference between gymnosperms and angiosperms.
61. Which of the following plants produces seeds but not flowers?
(a) maize
(b) mint
(c) peepal
(d) Pinus.
Answer and Explanation:
61. (d): Pinus belong to order coniferales of Gymnosperms. The plant is differentiated into root, stem and leaves. Plants are monoecious. Both male and female cones are borne on the same plant. It develops clusters of shortly stalked male cones subterminally on the lower branches and female cones in circle of 2 – 6 on upper long branches.
A male cone has a central axis and a number of spirally arranged microsporophylls. A microsporophyll bears two oblong microsporangia abaxially on the proximal part. The terminal flattened part is bent and sterile. IV microsporangium produces a large number of yellow pollen grains. Each pollen grain has two wings or air sacs for floating in the air.
The central axis of female cone bears paired scales. In each pair the lower scale is bract scale while the upper one is ovuliferous scale (= megasporophyll complex), the terminal sterile part of ovuliferous scale is broad and called apophysis. The proximal adaxial side bears two ovules.
62. Which of the following is without exception in angiosperms?
(a) presence of vessels
(b) double fertilisation
(c) secondary growth
(d) autotrophic nutrition.
Answer and Explanation:
62. (b): In angiosperms presence of vessels is not an universal feature as there are certain angiosperms where vessels are absent e.g. Wintera, Trochodendron etc. Secondary growth is increase in the girth or diameter of axis (root and stem) of the plant by formation of secondary tissue by the activity of lateral meristein.
It occurs in dicotyledons of angiosperms and gymnosperms. But in monocotyledons of angiosperms the primary plant body is complete in it and doesn’t produce any secondary tissue.
Autotrophic plants are those which synthesise their organic food themselves by the process of photosynthesis. But certain angiospermic plants have heterotrophic mode of nutrition, e.g. Rafjlesia, Orobanche, Striga are root parasites.
But double fertilization is universal in all angiosperms. It involves fusion of one male gamete with the egg cell and another male gamete with the diploid secondary nuclei.
63. Which one pair of examples will correctly represent the grouping spermatophyta according to one of the schemes of classifying plants?
(a) Acacia, sugarcane
(b) Pinus, Cycas
(c) Rhizopus, Triticum
(d) Ginkgo, Pisum
Answer and Explanation:
63. (d): Spermatophyta includes seed bearing plants and this includes gymnosperms and angiosperms. Acacia and sugarcane both are angiosperms. Pinus and Cycas both are gymnosperms. Rhizopus belongs to kingdom fungi and Tritcum is an angiosperm. Ginkgo is gymnosperm and Pisum is an angiosperm. So Ginkgo and Pisum correctly represent the grouping spermatophyta.
64. Plants reproducing by-spores such as mosses and ferns are grouped under the general term
(a) cryptogams
(b) bryophytes
(c) sporophytes
(d) thallophytes
Answer and Explanation:
64. (a): Eichler divided plant kingdom into two sub- kingdoms – cryptogamae and phanerogamae. All plants without flowers and seeds are included in the sub-kingdom cryptogamae whereas phanerogamae includes plants which bear flowers and seeds.
Cryptogams are further classified into three divisions. Thallophyta, Bryophyta and Pteridophyta. Spore bearing plants such as mosses and ferns belong to cryptogams because instead of reproducing by flowers and seeds they reproduce by means of spores.
65. Sexual reproduction in Spirogyra is an advanced feature because it shows
(a) different sizes of motile sex organs
(b) same size of motile sex organs
(c) morphologically different sex organs
(d) physiologically differentiated sex organs
Answer:
(d) physiologically differentiated sex organs
66. Which one of the following pairs of plants are not seed producers?
(a) Fern and Funaria
(b) Funaria and Ficus
(c) Ficus and Chlamydomonas
(d) Funaria and Pinus
Answer and Explanation:
66. (a): Seed producing plants belong to spermatophyta. It includes gymnosperms and angiosperms. Seed habit or seed formation originated in gymnosperms. It requires the retention of megasporangium or the only on the parent plant and non-shedding of megaspore, development of integument and in site formation of female gametophyte.
All these features developed in gymnosperms and angiosperms. Thallophytes, bryophytes and pteridophytes lack these features and thus do not reproduce by producing seeds.
Fern and Funaria belong to pteridophytes and bry ophytes respectively so they do not reproduce by producing seeds.
67. Angiosperms have dominated the land flora primarily because of their
(a) power of adaptability in diverse habitat
(b) property of producing large number of seeds
(c) nature of self pollination
(d) domestication by man.
Answer and Explanation:
67. (a): Angiosperms are highly evolved and well adapted land plants. They have both vessels and tracheids in xylem for better conduction of water. Roots are modified into tap roots, adventitious roots, pneumatophores etc. to suit the desired climate.
Sex organs are highly developed, sporophylls are organized into flowers and the flowers are highly coloured or modified to attract pollinators at different times and places insect pollination is more prevalent because it is more efficient and leads to less wastage of pollen grains as compared to wind pollination.
So the flowers are made attractive to attract a variety of insects. Seed are more protected as they are enclosed inside a fruit. All these adaptations have made angiosperms more adaptive in diverse habitats.
68. Diversification in plant life appeared
(a) due to long periods of evolutionary changes
(b) due to abrupt mutations
(c) suddenly on earth
(d) by seed dispersal.
Answer and Explanation:
68. (a): Diversification in plant life appeared due to long periods of evolutionary changes. Algae and bryophytes have thalloid plant body with no differentiation into root, stem and leaves. They had no vascular tissues but later in pteridophytes vascular tissues (xylem and phloem) developed and plant body became differentiated into root, stem and leaves.
But the vascular tissues lack vessels and companion cells and they reproduce by spores. In gymnosperms seed habit developed but the seeds are not enclosed inside fruit. In angiosperms vessels and companion cells are present, flowers are present and seeds are enclosed inside fruits. Thus the path of evolution is from algae to bryophytes to pteridophytes to gymnosperms and finally to angiosperm.
69. Top-shaped multiciliate male gametes, and the mature seed which bears only one embryo with two cotyledons, are characterised features of
(a) cycads
(b) conifers
(c) polypetalous angiosperms
(d) gamopetalous angiosperms.
Answer and Explanation:
69. (a): Cycas is an evergreen palm like plant. It belongs to order cycadales of gymnosperms. The plant body is sporophytic differentiated into root, stem and leaves; sexual reproduction is of oogamous type takes place by the fusion of distinct male and female gametes. The male and female gametes are formed by the germination of microspores and megaspores which are borne on microsporophylls and megasporophylls.
These microspores germinate to form male gametophyte that produces male gametes. The male gametes of Cycas are largest (300 jx) in nature, visible to naked eye, oval in form and top shaped. It is spirally coiled in the anterior half with thousands of small cilia.
After fertilization the ovule is connected into a seed. In the endosperm of seed lies a well developed embryo having two cotyledons, a plumule and a radicle.
70. Match items in Column 1 with those in Column II:
Column I – Column II
(A) Peritrichous (J) Ginkgo flagellation
(B) Living fossil (K) Macrocystis
(C) Rhizophore (L) Escherichia coli
(D) Smallest (M) Selaginella flowering plant
(E) Largest (N) Wolffia perennial alga
Select the correct answer from the following.
(a) A – L; B – J; C – M; D – N; E – K
(b) A – K; B – J; C – L; D – M; E – N
(c) A – N; B – L; C – K; D – N; E – J
(d) A – J; B – K; C – N; D – L; E – K.
Answer and Explanation:
70. (a): Flagellation is the arrangement of flagella over the body surface of a bacterial cell. Peritrichous flagellation has flagella all over the surface of a bacterial cell e.g. E. coli.
Ginkgo belongs to order ginkgoales of gymnosperms. It is called living fossil because it is the single living genus in a big fossilized order. Macrocystis belongs to class phaeophyceae. It is the largest perennial alga, about 40- 60 m in size. Wolffia is the smallest flowering plant. Rhizophore is a leafless, colourless, positively geotropic elongated structure that grows down from the point of bifurcation of stem. It occurs in Selaginella.
71. Ectophloic siphonostele is found in
(a) Osmunda and Equisetum
(b) Marsilea and Botrychium
(c) Adiantum and Cucurbitaceae
(d) Dicksonia and Maidenhair fern.
Answer and Explanation:
71. (a): Stele is a column containing vascular tissues which is surrounded by pericycle and separated from ground tissue by endodermis.
Siphonostele is medullated protostele or protostele with central non-vascular pith. Leaf gaps are absent. Siphonostele is of two types:
In Ectophloic siphonostele, central pith is surrounded successively by xylem, phloem, pericycle and endodermis. In amphiphloic siphonostele there is central pith and xylem is surrounded on either side by phloem, pericycle and endodermis. It is found in Osmunda and Equisetum.
72. Auxospores and hormogonia are formed, respectively, by
(a) some diatoms and several cyanobacteria
(b) some cyanobacteria and many diatoms
(c) several cyanobacteria and several diatoms
(d) several diatoms and a few cyanobacteria.
Answer and Explanation:
72. (d): Until 1907, auxospore formation was regarded as asexual process but now it is considered as an act of sexual process. The auxospores may be autogamous, isogamous, anisogamous or oogamous.
Their pattern of formation differs in pennate and centric diatoms. Formation of hormogonia is the common method of reproduction in Nostoc which is produced by accidental breaking of trichome into several pieces. It may also be formed by death and decay of ordinary intercalary cells. Soon, the hormogonium escapes from mucilage and grows into a new filament and then into a new colony.
73. In a moss, the sporophyte
(a) manufactures food for itself, as well as for the gametophyte
(b) is partially parasitic on the gametophyte
(c) produces gametes that give rise to the gametophyte
(d) arises from a spore produced from the gametophyte
Answer and Explanation:
73. (b): Mosses like Funaria are bryophytes. They are non-vascular plants. The main plant body is gametophytic (n) which is independent and foliose. It forms major part of the life cycle. The sporophytic phase starts with zygote which divides to form sporogenous tissue that is differentiated into foot, seta and capsule. The sporophytic phase is short lived. The foot absorbs nutrients and provides support to the sporophyte.
74. Conifers differ from grasses in the
(a) formation of endosperm before fertilization
(b) production of seeds from ovules
(c) lack of xylem tracheids
(d) absence of pollen tubes
Answer and Explanation:
74. (a): Conifers belong to gymnosperms. They are seed bearing plants in which the sporophylls are aggregated to form cones and the seeds develop in exposed state over the surface of megasporophylls. Vascular strand consists of tracheids and sieve cells. Female gametophyte forms archegonia, provides nourishment to developing embryo and later gets transformed into food-laden tissue or endosperm inside the seed.
This endosperm is formed before fertilization so it is haploid in nature. It provides nourishment for growth of seedlings at the time of seed germination. Grass is an anoiospermic plant and endosperm is produced after fertilization.
75. Peat moss is used as a packing material for sending flowers and lives plants to distant places because
(a) it serves as a disinfectant
(b) it is easily available
(c) it is hygroscopic
(d) it reduces transpiration
Answer and Explanation:
75. (c): The partially decomposed Sphagnum mass accumulates to form compressed mass called peat, which after drying is used as coal. So it is also called peat moss. Sphagnum has the capacity to retain water for long periods and thus it is used to cover plant roots during transportation.
76. In the prothallus of a vascular cryptogam, the antherozoids and eggs mature at different times. As a result
(a) there is high degree of sterility
(b) one can conclude that the plant is apomictic
(c) self fertilization is prevented
(d) there is no change in success rate of fertilization.
Answer and Explanation:
76. (c): In prothallus of vascular cryptogams the antherozoids and eggs mature at different times. The spore on germination gives rise to prothallus. The antherozoids are biflagellated or multiflagellated. The egg is produced inside the venter, water is essential for fertilization and it is always cross-fertilization. Self fertilization is prevented.
77. If you are asked to classify the various algae into distinct groups, which of the following characters you should choose?
(a) nature of stored food materials in the cell
(b) structural organization of thallus
(c) chemical composition of the cell wall
(d) types of pigments present in the cell.
Answer and Explanation:
77. (d): Algae are a group of chlorophyllous, nonvascular plants with thallose plant body. Different algae show different pigments present in the cell like chlorophyll – a, b, xanthophylls, carotenes etc. These pigments provide the base for classification of various groups of algae into different classes. Chlorophyceae possess Chlorophyll – a, b pigments, bacillariophyceae contains diatomin pigment, phaeophyceae has fucoxanthin, rhoaopl.yceae has r-phycocyanin and r- phycoerythrin, cyanophyceae has phycobilin pigment.
78. Flagellated male gametes are present in all the three of which one of the following sets?
(a) Zygnema, Saprolegnia and Hydrilla
(b) Fucus, Marsilea and Calotropis
(c) Riccia, Dryopteris and Cycas
(d) Anthoceros, Funaria and Spirogyra.
Answer and Explanation:
78. (c): Flagellated male gametes are mostly seen lower groups of plants like algae, bryophytes, pteridophytes. It is also seen in certain gymnosperms like Cycas. The bryophytes like Riccia have the male gametes which are biflagellate.
79. Spore dissemination in some liverworts is aided by
(a) indusium
(b) calyptra
(c) peristome teeth
(d) elaters.
Answer and Explanation:
79. (c): An elater is a cell (or structure attached to a cell) that is hygroscopic, and therefore will change shape in response to changes in moisture in the environment. Elaters come in a variety of forms, but are always associated with plant spores. In plants that do not have seeds, they function in dispersing the spores to a new location. In the liverworts, elaters are cells that develop in the sporophyte alongside the spores.
They are complete cells, usually with helcial thickenings at maturity that respond to moisture content. In most liverworts, the elaters are unattached, but in some leafy species (such as Frullania) a few elaters will remain attached to the inside of the sporangium (spore capsule). The elaters by hygroscopic movement help in spore dispersal.
80. In gymnosperms, the pollen chamber represents
(a) a cavity in the ovule in which pollen grains are stored after pollination
(b) an opening in the megagametophyte through which the pollen tube approaches the egg
(c) the microsporangium in which pollen grains develop
(d) a cell in the pollen grain in which the sperms are formed.
Answer and Explanation:
80. (c): In gymnosperms, pollen chamber represents the microsporangium in which pollen grains develop. The microspore is generally a globular sac like structure having large number of microspores. The microspores are also termed as pollen grains.