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In bryophytes [CBSE AIPMT 1994]
(d) 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 rise to gametophytic phase. The sporophyte is partially or full dependent upon the gametophyte and is of shorter duration.
Which one is the most advanced from evolutionary view point? [CBSE AIPMT 1993]
(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.
Pinus differs from mango in having [CBSE AIPMT 1993]
(c) Pinus is a gymnospermic plant which has a well developed conducting tissue system but seeds are naked. Whereas mango is an angiospermic plant in which seeds are enclosed in the ovary and fruit is present.
Pyrenoids are the centres for formation of [CBSE AIPMT 1993]
(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.
Pteridophytes differ from bryophytes and thallophytes in having [CBSE AIPMT 1993]
(a) Pteridophytes differ from bryophytes and thallophytes in having well developed vascular tissue system. Vascular tissues play an important role in conducting water and food materials to the plants. Whereas these are absent in bryophytes and thallophytes.
Chloroplast of Chlamydomonas is [CBSE AIPMT 1993]
(b) Chloroplast in Chlamydomonas is cupshaped. It is one-celled structure whereas stellate, spiral, and collar-shaped chloroplasts are present in Zygnema, Spirogyra, and Ulothrix respectively.
In Ulothrix/Spirogyra, reduction division (meiosis) occurs at the time of [CBSE AIPMT 1993]
(c) In Ulothrix/Spirogyra reduction division (meiosis) occurs at the time of zygospore formation. The plant body of Ulothrix and Spirogyra, is gametophytic (haploid), they produce zoogametes (n) which fuses to form zygosporic \((2 \mathrm{n})\) diploid, which is a resting spore. The onset of favourable condition zygospore undergoes reductional division, or meiosis to produce zoo-meiospores.
Pteridophytes differ from mosses/bryophytes in possessing [CBSE AIPMT 1993]
(b) Pteridophytes differ from bryophytes and thallophytes in having well developed vascular tissue system. Vascular tissues play an important role in conducting water and food materials to the plants. Whereas these are absent in bryophytes and thallophytes.
Protonema occurs in the life cycle of [CBSE AIPMT 1993,1990]
(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 the new plant.
Resin and turpentine are obtained from [CBSE AIPMT 1992]
(b) Resins and turpentine are obtained from Pinus which is gymnospermic plant. Cycas is an ornamental plant. Paper and Canada balsam are obtained from Abies and timber is obtained from Cedrus deodara.
Turpentine is got from [CBSE AIPMT 1992]
(c) Resins and turpentine are obtained from Pinus which is gymnospermic plant. Cycas is an ornamental plant. Paper and Canadian balsam are obtained from Abies and timber is obtained from Cedrus deodara.
In Pinus, the pollen grain has 6 chromosomes then in its endosperm will have [CBSE AIPMT 1992]
(c) In Pinus, if the pollen grain has 6 chromosomes then its endosperm will also have 6 chromosomes as endosperm and pollen grains are both haploid structures.
A plant having seeds but lacking flowers and fruits belongs to [CBSE AIPMT 1992]
(d) A plant having seed but lacking flowers and fruit belongs to gymnosperms. Gymnosperms are vascular land plants and bear seeds that are naked i.e., ovules not enclosed in the ovary. Hence, flowers are absent.
Which one of the following is not common between Funaria and Selaginella? [CBSE AIPMT 1992]
(d) Root is not common between Funaria and Selaginella. Funaria is a bryophyte and have archegonium, embryo, and flagellated sperms which are also present in Selaginella. Selaginella is a pteridophyte and it has root which is absent in Funaria.
The plant group that produces spores and embryo but lacks vascular tissues and seeds is [CBSE AIPMT 1992]
(c) Bryophytes are the plants that produce spores and embryos but they do not have vascular tissue system. While rhodophytes and phaeophytes are algae and produce spores (no embryos) only and pteridophytes produce spores, embryo, and a well-developed vascular tissue system.
A plant in which sporophytic generation is represented by zygote is [CBSE AIPMT 1992]
(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 fuses to produce diploid zygote which is the only sporophytic generation.
Bryophytes are amphibians because [CBSE AIPMT 1991]
(a) 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 archegonium that makes water essential for the completion of the life cycle of bryophytes.
Which one has the largest gametophyte? [CBSE AIPMT 1991]
(d) Moss has the largest gametophyte. Mosses are small, soft plants that are typically \(1-10 \mathrm{~cm}\) 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.
The common mode of sexual reproduction in Chlamydomonas is [CBSE AIPMT 1991]
(a) In Chlamysomonas sexual reproduction takes place through isogamy, anisogamy, and oogamy. Isogamy i.e., the fusion of similar gametes is the common mode of sexual reproduction in it. Anisogamy is fusion of morphologically similar but physiologically different cells. Oogamy is fusion of different gametes.
The product of conjugation in Spirogyra or fertilization of Chlamydomonas is [CBSE AIPMT 1991]
(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.
Moss peristome takes part in [CBSE AIPMT 1990]
(a) Moss peristome is present in the capsule and takes part in spore dispersal. The hygroscopic action of peristomial teeth helps in the removal of the 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
Apophysis in the capsule of Funaria is [CBSE AIPMT 1990]
(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.
In Pinus/gymnosperms, the haploid structure are [CBSE AIPMT 1989]
(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.
Sperms of both Funaria and Pteris were released together near the archegonia of Pteris. Only its sperms enter the archegonia as [CBSE AIPMT 1989]
(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 release a chemical malic acid to attract its sperms for fertilization.
Evolutionary important character of Selaginella is [CBSE AIPMT 1989]
(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.
In Pinus/Cycas/gymnosperms, the endosperm is [CBSE AIPMT 1988]
(b) In Pinus/Cycas/gymnosperms the endosperm is haploid because it is produced before fertilization.
Prothallus (gametophyte) gives rise to fern plant (sporophyte) without fertilization. It is [CBSE AIPMT 1988]
(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.
Sexual reproduction involving fusion of two cells in Chlamydomonas is [CBSE AIPMT 1988]
(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 the fusion of two gametes, zygospore is formed.
Which of the following algae contains mannitol as reserve food material? [NEET 2021]
(a) Ectocarpus is a cosmopolitan marine brown seaweed. Mannitol is stored as a food reserve in Ectocarpus. Other options can be explained as:
– Gracilaria is also a type of red algae that is notable for its economic importance. Reserved food found in Gracilaria is in the form of floridean starch, which is similar to amylopectin and glycogen in structure.
– In Volvox (green algae), the stored food material is starch and the major pigments are chlorophyll a and d. Some may store food as oil droplets.
– Ulothrix is a genus of non-branching filamentous green algae, starch molecule is the reserved food.
Which of the following algae produces carrageen? [NEET 2021]
(c) Carrageen is a common name give to polysaccharides (carbohydrates) that are extracted from seaweeds like red algae. Carrageen is known for its gelling properties and it is one of the industrial source of carrageenan that is utilised as a stabilizer and thickner of milk products. It can be harmful to immune system, in severe cases it leads to internal bleeding.
Gemmae are present in [NEET 2021]
(d) Some liverworts reproduce asexually by fragmentation of thalli or by the formation of gemmae. (green,multicellular asexual buds). The gemmae are held in special organs known as gemma cups and are dispersed by rainfall. Gemmae become detached from the parent body and germinate to form new individuals.
Which of the following pairs is of unicellular algae? [NEET 2020]
(c) Chlorella and Spirulina are unicellular algae. Gelidium, Gracilaria, Laminaria and Sargassum are multicellular. Volvox is colonial.
Chlorella is the most cultivated eukaryotic alga since it is widely used as a health food and feed supplement, as well as in the pharmaceutical and cosmetics industry. It contains proteins, carotenoids, some immuno-stimulators, polysaccharides, vitamins, and minerals.
Floridean starch has structure similar to [NEET 2020]
(d) Floridean starch is stored food material in red algae. Its structure is similar to Amylopectin and Glycogen.
Floridean starch is a type of a storage glucan found in glaucophytes and in red algae (also known as rhodophytes), in which it is usually the primary sink for fixed carbon from photosynthesis.
Which one is wrongly matched? [NEET 2018]
(a) Polysiphonia is a genus of red algae, where asexual spores and gametes are nonmotile or non-flagellated.
After karyogamy followed by meiosis, spores are produced exogenously in [NEET 2018]
(d) In Agaricus (a genus of basidiomycetes), basidiospores or meiospores are produced exogenously. Neurospora (a genus of ascomycetes) produces ascospores as meiospores but endogenously inside the ascus). Alternaria (a genus of deuteromycetes) does not produce sexual spores. Saccharomyces (Unicellular ascomycetes) produces ascospores, endogenously.
Which one of the following shows isogamy with non-flagellated gametes? [CBSE AIPMT 2014]
(d) In Spirogyra, sexual reproduction occurs through conjugation. Gametes are non-flagellated, and morphologically similar. But physiologically different (isogamy with physiological anisogamy).
Conjugation is the biological process by which one bacterium transfers genetic material to another bacterium through direct contact. During conjugation, one bacterium serves as the donor of the genetic material, and the other serves as the recipient. The donor bacterium carries a DNA sequence called the fertility factor, or F-factor.
An alga which can be employed as food for human being is: [CBSE AIPMT 2014]
(b) Chlorella and Spirullina are unicellular algae, rich in proteins and are used as food supplements by space travellers.
Which of the following is not correctly matched for the organism and its cell wall degrading enzyme? [NEET 2013]
(b) Algae is a plant and so its cell wall is made up of cellulose. Cellulase enzyme is needed for degradation of its cell wall.
Floridean starch is found in [CBSE AIPMT 2000]
(b) Reserve food in red algae (Rhodophyceae) is floridean starch. In green algae, (Chlorophyceae), the reserve food is starch. In brown algae, reserve food is laminarin and mannitol. In cyanophyceae, the reserve food is cyanophycean starch.
Columella is a specialised structure found in the sporangium of [CBSE AIPMT 1999]
(b) Ulothrix is a green alga. Spirogyra is a filamentous green alga. In Rhizopus the columella bears the spores for asexual reproduction.
Columella is located on the tip of long erect stalk known as sporangiophore, present in the Rhizopus. It supports the Sporangium which has asexual spores. It helps nutrient exchange between the active protoplasm below and the developing spores inside the upper portion of the sporangial head.
Blue-green algae belong to [CBSE AIPMT 1996]
(b) Blue green algae or cyanobacteria are prokaryotes. Prokaryotes lack a well-defined nucleus surrounded by nuclear membrane. Eukaryotes have well organised nucleus. Rhodophyceae & Chlorophyceae are members of algae which come under eukaryotes.
The absence of chlorophyll, in the lowermost cell of Ulothrix, shows [CBSE AIPMT 1995]
(d) The plant body of Ulothrix is divided into three regions-basal cells, apical cells, and middle cells. Basal cell is the lowermost cell of the filament. It expands and forms a disc-shaped structure called holdfast. It is meant for attaching the filaments to the substratum which shows the beginning of labour division.
Agar is commercially obtained from [CBSE AIPMT 1995]
(a) The agar is obtained from several members of red algae such as Gracilaria, Gelidium, Chondrus, etc. Agar gels are extensively used for growing micro-organisms.
Which of the following cannot fix nitrogen? [CBSE AIPMT 1994]
(c) Spirogyra is a member of green algae which cannot fix atmospheric nitrogen. Only Nostoc and Anabaena (Blue-green algae) and Azotobacter (bacteria) can fix nitrogen.
Which one is the wrong statement? [NEET 2015]
(a) The spores are non-motile in Mucor.Â
Some hyperthermophilic organisms that grow in highly acidic \(\left(\mathrm{PH}_{2}\right)\) habitats belong to the two groups: [CBSE AIPMT 2010]
(a) Hyperthermophilic organism that grows in highly acidic habitats belong to eubacteria and archaea groups.
Which of the following propagates through leaf-tip? [CBSE AIPMT 2004]
(a) In mosses, vegetative propagation occurs by fragmentation. Marchantia is a liverwort in which propagation also occurs by fragmentation. Walking fern Adiantum propagates through leaf tip.
In which one of these elaters are present along with mature spores in the capsule (to help in spore dispersal)? [CBSE AIPMT 1996]
(b) In Marchantia, capsule elaters are present which help in the dispersal of spores.
Unique features of Bryophytes is that they [CBSE AIPMT 1994]
(b) In bryophytes, the plant body is gametophyte. Sporophyte remains attached to the gametophyte and produces spores. Sporophyte is dependent on gametophyte.
The ‘amphibians’ of plant kingdom are [CBSE AIPMT 1996]
(c) Bryophytes are terrestrial plants but they require a thin film of water on the surface of their substratum during sexual reproduction, hence they are called amphibians of the plant kingdom.
Strobili or cones are found in [NEET 2020]
(c) Strobili or cones are found in Equisetum. Strobili or cones are the dense and compact structure present on non-flowering plants. They contain sporangia and perform the function of protecting spores from wild animals and harsh conditions of the environment.
Equisetum is the only living genus in Equisetaceae, a family of vascular plants that reproduce by spores rather than seeds.
Pinus seed cannot germinate and establish without fungal association. This is because: [NEET 2019]
(b) Fungus associated with roots of Pimus increases minerals and water absorption for the plant by increasing surface area and in turn fungus gets food from the plant. Therefore, mycorrhizal association is obligatory for Pinus seed germination.
Phloem in gymnosperms lacks: [NEET 2019]
(d) Phloem, a complex tissue, is found in highly organised plants (“higher plants”) and characterised by the possession of certain specialised cells, the sieve elements, and which functions as the major channel of rapid conduction of sugars over fairly long distances in the plant body. In addition to sieve elements, it always contains parenchyma cells, usually of more than one type, and frequently includes sclerenchyma cells.
Phloem in gymnosperms lacks both sieve tube and companion cells.
Select the wrong statement: [NEET 2018]
(d) Pseudopodia are locomotory structures in sarcodines (amoeboid).
Besides paddy fields cyanobacteria are also found inside the vegetative part of: [NEET 2013]
(a) In Cycas specialised root called coralloid roots are associated with \(\mathrm{N}_{2}\)-fixing cyanobacteria either Nostoc or Anabaena. Coralloid roots lie near the soil surface. They are irregular and often dichotomously branched. Root hair and root cap are absent in these roots.
Which one of the following is a living fossil? [CBSE AIPMT 2003, 2004]
(a) Cycas revoluta a native of China and Japan is commonly known as “Tesso” or Sago palm. It is also called a living fossil due to its primitive characters.
Which one of the following is a living fossil? [CBSE AIPMT 1996,1997,2003]
(c) Ginkgophyta is an ancient group, of which the sole living representative or living fossil is Ginkgo biloba or Maiden hair tree. It is native of South China.
The ‘wing’ of Pimus seed is derived from [CBSE AIPMT 1994]
(c) The ovule matures into seed and is provided with wings. The upper surface of ovuliferous scale forms the membranous wings of the seed which helps in dispersal of the seed. The time taken from cone formation to seed dispersal is about two years in Pinus.
Double fertilization is exhibited by: [NEET 2017]
(c) Double fertilisation is a unique feature exhibited only by angiosperms. It involves both syngamy and triple fusion.
Male gametophyte in angiosperms produces: [CBSE AIPMT 2015]
(d) Two sperms and a vegetative cell are produced by male gametophyte in angiosperms.
In angiosperms, microsporogenesis and megasporogenesis: [CBSE AIPMT 2015]
(b) In meiosis, the number of chromosomes are reduced by half producing haploid daughter cells. The microspore mother cell and the megaspore mother cell undergo meiosis to produce haploid microspore and megaspore respectively.
In angiosperms, functional megaspore develops into [Mains 2011]
(a) During megagametogenesis functional megaspore (mostly chalazal) gives rise to embryo sac. This is the mature female gametophyte generation.
The largest ovules, largest male and female gametes and largest plants are found among [CBSE AIPMT 2000]
(c) Egg of Cycas (Gymnosperms) and its nucleus are the largest in the plant kingdom. The sperms of Cycas are also the largest in the plant kingdom.
Seed-habit first originated in [CBSE AIPMT 1996]
(a) Seed habit originated in Cycadophiles or pteridosperms.
Sunken stomata is the characteristic feature of [CBSE AIPMT 1995]
(c) Sunken stomata is the characteristic feature of xerophytes which help in reducing loss of water from leaf surface. These type of stomata are found in Oleander or pine.
Phycoerythrin is the major pigment in [NEET 2020]
(a) Phycoerythrin is the major pigment in red algae or rhodophytes. The
photosynthetic pigments in red algae include chlorophyll-a, carotenoids, and phycobilins. Phycoerythrin belongs to the phycobilins. These pigments are soluble in water.
A research student collected certain alga and found that its cells contained both chlorophyll-a,b,c, and chlorophy ll-d as well as phycoerythrin. The alga belongs to [CBSE AIPMT 2000]
(a) Members of Rhodophyceae(red algae)
contains Chlorophyll-a, d,
\(r\)-phycoerythrin, \(r\)-phycocyanin, \(\alpha\) and \(\beta\)-carotene pigments.
Members of Chlorophyceae (green algae)
contain chlorophyll-a, \(b\) and \(\beta\)-carotene pigments.
Members of Bacillariophyceae(diatoms)
contain chlorophyll-a, \(c, \beta\)-carotene,
\(\alpha\)-carotene pigments.
Members of Cyanophyceae
(cyanobacteria, blue-green algae) contain
chlorophyll-a, c-phycocyanin,
\(c\)-phycoerythrin and \(\beta\)-carotene pigments.
Acetabularia used in Hammerling’s nucleocytoplasmic experiments is [CBSE AIPMT 1988]
(c) Acetabularia is the largest uninucleated green marine alga popularly called
the mermaids wine glass umbrella plant. It has a cap, stalk and rhizoidal base and nucleus lies in the base. Danish biologist J Hammerling (1953) by his grafting experiments involving the exchange of nucleus in Acetabularia proved the role of nucleus in heredity, growth, morphology, differentiation, and morphogenesis.
Unique features of bryophytes are that they [CBSE AIPMT 1994]
(b) The main plant body of bryophytes is gametophytic which is independent and
may be thallose or foliose. The sporophyte is differentiated into foot, seta, and capsule and is partially or fully dependent upon the gametophyte.
Which one of the following is a correct statement? [NEET 2013]
(d) Origin of seed habitat can be traced in pteridophytes. Some pteridophytes like Selaginella and Salvinia are heterosporous as they produce two kinds of spores micro (small) spores and macro (large) spores, which germinate and give rise to male and female gametophyte respectively. The female gametophyte in these plants are retained on the parent sporophytes for variable periods. The development of the zygote into young embryos takes place within the female gametophyte. This event is the precursor to the seed habit and is considered an important step in evolution.
Which of the following statements is incorrect about gymnosperms? [NEET 2020]
(b) Statement(b)is incorrect. It can be corrected as, In gymnosperms, the male and the female gametophyte do not have an independent free-living existence. The male gametophyte remains within the sporangia, retained on the sporophytes, and is dependent on sporophyte.
Which one of the following statements is correct? [NEET 2018]
(c) In gymnosperms, ovules are not enclosed by ovary wall. Seeds do not occur inside a fruit. They are naked. Horsetail is the common name of Equisetum.
Pteridophytes like Selaginella and Salvinia are heterosporous and possess two types of spores, i.e. microspores and megaspores. Cycas has an unbranched columnar stem while Cedrus possess branched stem. Therefore, only statement (c) is correct.
Gymnosperms are also called soft wood spermatophytes because they lack [CBSE AIPMT 2012]
(d) Gymnosperms lack xylem fibres. Large amount of parenchymatous cells are
present with secondary xylem tracheids. So, these are also known as softwood spermatophytes.
Male and female gametophytes do not have an independent free-living existence in [NEET (Oct.) 2020]
(c) Male and female gametophyte do not have an independent free-living existence in gymnosperms and angiosperms. In them, they remains within the sporangia retained on the sporophytes. The pollen grain is released from the microsporangium and are carried in air currents and comes in contact with the opening of the ovules borne on megasporophylls. The pollen tube carrying the male gametes grows towards archegonia in the ovules and discharges its contents near the mouth of the archegonia.
Which is the most common type of embryo sac in angiosperms? [NEET (Odisha) 2019]
(b) The most common type of female gametophyte (embryo sac) in angiosperms is the monosporic embryo sac in which the embryo sac develops from a single functional megaspore (n) while the other three megasproes degenerate. The functional megaspore
undergoes three sequential mitotic divisions and gives rise to 8 -nucleate and 7-celled mature embryo sac.
Metagenesis refers to [CBSE AIPMT 2015]
(b) Metagenesis in an organism refers to the reproduction characterised by the alteration of a sexual generation and a generation that reproduces asexually, i.e. alteration of generations.
Genera like Selaginella and Salvinia produce two kinds of spores. Such plants are known as [NEET 2023]
(a) Genera like Selaginella and Salvinia which produce two kinds of spores, macro (large) and micro (small) spores, are known as heterosporous.
Which one of the following is wrong about Chara? [AIPMT]
(c) All species of Chara reproduce sexually and show highly advanced oogamy. The sex organs are the most distinctive features of the Order Charales and are the most complicated among the thallophytes. Male and female gametangia are called antheridia and oogonia respectively. Male fructification (cluster of antheridia) is called globule and the female is nucule. They are borne at the nodes of short branches, globule towards the lower side, and nucule (female structure) towards the upper side.
Isogamous condition with non-flagellated gametes is found in [NEET 2024]
(d) Isogamy is found in Spirogyra in which both gametes are non-motile. In Chlamydomonas, all three conditions, isogamy anisogamy, and oogamy are found. Both motile and non-motile gametes are found. In Volvox and Fucus, oogamy is present, where non-motile egg fuses with motile sperm.
Assertion: Sphagnum is slowly carbonised, compressed and fossilised over thousands of years to produce a dark spongy mass called peat.
Reason: Peat helps to keep soil porous and it also improves water holding capacity of the soil. [AIIMS]
(b) If both assertion and reason are true but reason is not the correct explanation of assertion.
From evolutionary point of view, retention of the female gametophyte with developing young embryo on the parent sporophyte for some time, is first observed in [NEET 2024]
(d) In Pteridophytes, megaspore is retained for some times in female gametophyte. However, permanent retention is required for seed formation and hence seed is not formed.
That’s why Pteridophytes are said to be precursors of seed habit.
So, the correct answer is ‘Pteridophytes’
Which one is wrongly matched? [NEET 2017]
(a) A non-motile male gamete or spermatium is the characteristic feature of Polysiphonia.
Match column I with column II and select the correct option from the given codes. [AIIMS]
\(\begin{array}{|c|l|c|l|}
\hline & \text { Column I } & & \text { Column II } \\
\hline \text { A. } & \text { Chlorophyta } & \text { (i) } & \text { Equisetum } \\
\hline \text { B. } & \text { Lycopsida } & \text { (ii) } & \text { Chara } \\
\hline \text { C. } & \text { Phaeophyta } & \text { (iii) } & \text { Selaginella } \\
\hline \text { D. } & \text { Sphenopsida } & \text { (iv) } & \text { Ectocarpus } \\
\hline
\end{array}\)
(a) Correct answer is (a), (A) – (ii), (B) – (iii), (C) – (iv), (D) – (i)Â
Which of the following statements is correct? [NEET 2018]
(a) Gymnosperms have naked ovule. Selaginella and Salvinia both produce two kinds of spores, macro (large) and micro (small) hence, called heterosporous. Equisetum (horsetail, scouring rush) is a pteridophyte. Stems are branched in Cedrus but unbranched in Cycas.
Conifers are adapted to tolerate extreme environmental conditions because of [NEET 2019]
(c) Needle like leaves with thick cuticle and sunken stomata are xerophytic adaptations of conifers for tolerating extreme environmental conditions.
Read the following statements (A-E) and answer the question which follows them. [NEET 2022]
(A) In liverworts, mosses and ferns gametophytes are free-living.
(B) Gymnosperms and some ferns are heterosporous.
(C) Sexual reproduction in Fucus, Volvox, and Albugo is oogamous.
(D) The sporophyte in liverworts is more elaborate than that in mosses.
(E) Both Pinus and Marchantia are dioecious.
How many of the above statements are correct?
(a) Gametophytes of liverworts, mosses, and ferns are independent and so are free-living.
Gymnosperms and some ferns are heterosporous, meaning that they have two different types of spores.
Sexual reproduction in Fucus, Volvox, and Albugo is oogamous meaning they have small flagellated male gamete and large non-flagellated female gamete. The sporophyte of moss is more elaborate than the liverworts. Pinus is monoecious while Marchantia is dioecious. Thus, the correct answer is option (a), ‘Three’.
An example of colonial alga is [NEET 2024]
(a) Volvox is motile colonial fresh water alga with definite number of vegetative cells.
Which of the following plants is monoecious? [NEET 2020]
(c) Chara is an alga with monoecious condition. It has male sex organ antheridium and female sex organ oogonium at the same node. Cycas circinalis, Carica papaya, and Marchantia polymorpha are dioecious.
Life cycles of Ectocarpus and Fucus respectively, are [NEET 2019]
(b) Ectocarpus possesses haplodiplontic whereas Fucus possesses diplontic life cycle.
Gemmae are present in [NEET 2019]
(a) In some liverworts like Marchantia, special structures called gemmae are present for asexual reproduction.
Which of the following algae contains mannitol as reserve food material? [NEET 2020]
(b) Mannitol is reserve food material in phaeophyceae, e.g., Ectocarpus.
Which one of the following statements is wrong? [NEET 2023]
(b) Alginic acid is obtained from brown algae whereas carrageenin is obtained from red algae.
Compared with the gametophytes of the bryophytes, the gametophytes of vascular plants tend to be [AIPMT]
(d) The plant kingdom is made up of nonvascular and vascular plants. Living groups of nonvascular plants include the bryophytes such as liverworts, hornworts, and mosses. Examples of vascular plants are pines, ferns, corn, and oaks. Comparing the gametophytes of vascular and nonvascular plants it is found that the gametophytes of the vascular plants are not only smaller but also bear smaller sex organs.
Therefore, the correct answer is option d.
Algae have cells made up of [AIPMT]
(a) Majority of algae (eukaryotes) possess a definite cell wall containing cellulose and other carbohydrates. In the algal cell walls, different chemical components are present which vary widely among different groups (e.g., xylan, mannan, galactan, alginic acid, silica, agar, pectin, carrageenin, etc.). The cell wall of blue-green algae is made up of micro-peptides (proteins). This micro-peptide is not found in eukaryotic algae.
Which of the following is responsible for peat formation? [AIPMT]
(d) Among the bryophytes Sphagnum accounts by far the most important place economically. It is popularly called bog moss or peat moss. It is perennial and its growth continues year after year. Older portions undergo death but do not decompose due to secretion of acid that accounts for the antibacterial and antifungal actions. The increasing mass of dead remains accumulate year after year and form a compact dark coloured mass rich in carbon which is called peat. Peat is used as fuel. Paraffin, acetic acid, peat tar, and ammonia are formed as by-products of peat obtained for industrial uses.
Floridean starch has structure similar to [NEET 2024]
(b) In Rhodophyceae, food is stored as floridean starch which is very similar to amylopectin and glycogen in structure.
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