Question
Which of the following statements is incorrect about gymnosperms? [NEET (Oct.) 2020]
(a) They are heterosporous
(b) Male and female gametophytes are free living
(c) Most of them have narrow leaves with thick cuticle
(d) Their seeds are not covered
Answer/Explanation
Ans. (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.
Question
Which one of the following statements is correct? [NEET 2018]
(a) Horsetails are gymnosperms
(b) Selaginella is heterosporous, while Salvinia is homosporous
(c) Ovules are not enclosed by ovary wall in gymnosperms
(d) Stems are usually unbrancned in both Cycas and Cedrus.
Answer/Explanation
Ans. (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.
Question
Select the correct statement. [NEET 2016, Phase I]
(a) Salvinia, Ginkgo and Pinus all are gymnosperms
(b) Sequoia is one of the tallest trees
(c) The leaves of gymnosperms are not well adapted to extremes of climate
(d) Gymnosperms are both homosporous and heterosporous
Answer/Explanation
Ans. (b)
Sequoia is one of the tallest tree species, known as red wood tree. It is a gymnospermic plant.
Salvinia is an angiosperm, but Ginkgo and Pinus are gymnosperms. Gymnosperms are well adapted to extremes of climate and are heterosporous.
Question
Conifers are adapted to tolerate extreme environmental conditions because of [NEET 2016, Phase II]
(a) broad hardy leaves
(b) superficial stomata
(c) thick cuticle
(d) the presence of vessels
Answer/Explanation
Ans. (c)
Conifers are gymnosperms. Their leaves show xerophytic adaptations. The leaves are like needle with thick. walled single layered epidermal cells covered with thick cuticle. This enables them to tolerate extreme climatic conditions.
Question
Read the following statements and answer the question which follows them
I. In liverworts, mosses and ferns gametophytes are free living.
II. Gymnosperms and some ferns are heterosporous.
III. Sexual reproduction in Fucus, Volvox and Albugo is oogamous.
IV. The sporophyte in liverworts is more elaborate than that in mosses.
How many of the above statements are correct? [NEET 2013]
(a) One
(b) Two
(c) Three
(d) Four
Answer/Explanation
Ans. (c)
Statement I, II and III are correct.
Statement IV is incorrect and can be corrected as the sporophyte in mosses is more elaborate than in liverworts.
Question
Cycas and Adiantum resemble each other in having [NEET 2013]
(a) seeds
(b) motile sperms
(c) cambium
(d) vessels
Answer/Explanation
Ans. (b)
Multiciliated motile sperms are found in both Cycas (gymnosperm) and Adiantum or walking fern (pteridophyte).
Seeds and cambium are present in Cycas (quite common in gymnosperms) but absent in pteridophytes. Vessels are absent in both.
Question
Gymnosperms are also called soft wood spermatophytes because they lack [CBSE AIPMT 2012]
(a) cambium
(b) phloem fibres
(c) thick-walled tracheids
(d) xylem fibres
Answer/Explanation
Ans. (d)
Gymnosperms lack xylem fibres. Large amount of parenchymatous cells are present with secondary xylem tracheids. So, these are also known as softwood spermatophytes.
Question
The gametophyte is not an independent, free living generation in [CBSE AIPMT 2011]
(a) Adiantum
(b) Marchantia
(c) Pinus
(d) Polytrichum
Answer/Explanation
Ans. (c)
In gymnosperms, (e.g. Pinus, Cycas, etc.) the male and female gametophytes do not have an independent free-living existence. They remain within the sporangia retained on the sporophytes.
Question
Select one of the following pairs of important features distinguishing Gnetum from Cycas and Pinus and showing affinities with angiosperms [CBSE AIPMT 2008]
(a) absence of resin duct and leaf venation
(b) presence of vessel elements and absence of archegonia
(c) perianth and two integuments
(d) embryo development and apical meristem
Answer/Explanation
Ans. (b)
The presence of vessels in the xylem is an angiospermic character found in Gnetum which distinguish it from $\mathrm{Cycas}$ and Pinus.
Gnetum resembles angiosperms in many other aspects also like
(i) The leaves in Gnetum have reticulate venation that is an angiospermic character.
(ii) In Gnetum female gametophyte is only partly cellular before fertilisation and becomes completely cellular only after fertilisation. Some of the free nuclei act as eggs as there are no archegonia.
The short apices in Gnetum and angiosperms show a distinct tunica and corpus configuration.
The cortex of stem of Pinus is traverse by large resin ducts or canals. Each duct or canal is lined by a layer of thin walled parenchymatous glandular secretory cells constituting epithelium. The epithelial cells secrete resin into canal. Resin is the chief source of terpentine.
Question
Flagellated male gametes are present in all the three of which one of the following sets? [CBSE AIPMT 2007]
(a) Anthoceros, Funaria and Spirogyra
(b) Zygnema, Saprolegnia and Hydrilla
(c) Fucus, Marselia and Calotropis
(d) Riccia, Dryopteris and Cycas
Answer/Explanation
Ans. (d)
Flagellated male gametes are present in Riccia, Dryopteris and Cycas.
Question
In gymnosperms, the pollen chamber represents [CBSE AIPMT 2007]
(a) a cell in the pollen grain in which the sperms are formed
(b) a cavity in the ovule in which pollen grains are stored after pollination
(c) an opening in the megagametophyte through which the pollen tube approaches the egg
(d) the microsporangium in which pollen grains develop
Answer/Explanation
Ans. (b)
In gymnosperms, the pollen chamber is a cavity in the ovule in which pollen grains are stored after pollination.
Question
Which one of the following is a living fossil?[CBSE AIPMT 2004, 03]
(a) Cycas
(b) Moss
(c) Saccharomyces
(d) Spirogyra
Answer/Explanation
Ans. (a)
The Cycadales is an ancient order of gymnosperms exhibiting several primitive features-now having only a few living representative of once a large group of plants that glorified during the Mesozoic era. Therefore, Cycas is called as living fossil.
Question
Which one pair of examples will correctly represent the grouping spermatophyta according to one of the schemes of classifying plants? [CBSE AIPMT 2003]
(a) Rhizopus, Triticum
(b) Ginkgo, Pisum
(c) Acacia, sugarcane
(d) Pinus, Cycas
Answer/Explanation
Ans. (b)
Ginkgo is a gymnospermic plant so it comes before angiospermic plant, Pisum (pea). Rhizopus is a fungus and Triticum (wheat) is an angiospermic plant.
Option (c) has both angiospermic plants and option (d) has both gymnospermic plants.
Question
Which of the following plants produces seeds but not flowers? [CBSE AIPMT 2002]
(a) Maize
(b) Mint
(c) Peepal
(d) Pinus
Answer/Explanation
Ans. (d)
Pinus is a gymnospermic plant. Ovules of Pinus are uncovered which lie on the megasporophyll, hence, these plants do not have flowers. However, it produces seeds (from ovule after fertilisation) like other three plants mentioned, all of which are angiosperms.
Question
Cycas has two cotyledons but not included in angiosperms because of [CBSE AIPMT 2001]
(a) naked ovules
(b) seems like monocot
(c) circinate ptyxis
(d) compound leaves
Answer/Explanation
Ans. (a)
Gymnosperms (Gk. gymnos-naked; sperma-seed e.g. naked seed plants) is a group of phanerogams which have naked ovules, i.e. structure (ovules) that eventually become the seeds after fertilisation and not completely enclosed by the tissues of the parent individual.
Question
The largest ovules, largest male and female gametes and largest plants are found among [CBSE AIPMT 2000]
(a) angiosperms
(b) tree ferns and some monocots
(c) gymnosperms
(d) dicotyledonous plants
Answer/Explanation
Ans. (c)
Cycas with largest antherozoids and ovule and the largest plant Sequoia belong to gymnosperms.
Gymnosperm is a group of naked seeded plants, i.e. their ovules are not enclosed by ovary walls. Ovules of gymnosperms are directly borne on the megasporophyll.
Question
In which of the following would you place the plants having vascular tissue, lacking seeds? [CBSE AIPMT 1999]
(a) Algae
(b) Bryophytes
(c) Pteridophytes
(d) Gymnosperms
Answer/Explanation
Ans. (c)
Pteridophytes and gymnosperms do have vascular tissues. However, gymnosperms bear seeds while pteridophytes not bear seeds. Algae and bryophytes do not possess vascular tissues.
Question
Largest sperms in the plant world are found in [CBSE AIPMT 1998]
(a) Pinus
(b) Banyan
(c) Cycas
(d) Tsuja
Answer/Explanation
Ans. (c)
Cycas is a gymnospermic plant. It has the biggest sperms (antherozoids) and ovules in the plant world.
Question
Which one of the following statements about Cycas is incorrect? [CBSE AIPMT 1998]
(a) It does not have a well organised female flower
(b) It has circinate vernation
(c) Its xylem is mainly composed of xylem vessels
(d) Its roots contain some blue-green algae
Answer/Explanation
Ans. (c)
Statements (c) is incorrect regarding Cycas as Vessels are absent from the xylem of all gymnosperms (except Gnetales). Cycas belongs to Cycadales (not Gnetales).
Question
Seed habit first originated in [CBSE AIPMT 1996]
(a) certain ferns
(b) certain pines
(c) certain monocots
(d) primitive dicots
Answer/Explanation
Ans. (a)
The tendency towards seed formation is called seed habit. It was developed in fossil gymnosperm of group
Cycadofilicales (pteridosperms), i.e. seed ferns, e.g. Lyginopteris which bears characters of cycads and ferns both. Seed habit is shown by few pteridophytes like Selaginella, Marselia, Isoetes, etc. which exhibit heterospory.
Question
The ‘wing’ of Pinus seed is derived from [CBSE AIPMT 1994]
(a) testa
(b) testa and tegmen
(c) surface of ovuliferous scale
(d) All of the above
Answer/Explanation
Ans. (c)
The winges of seed of Pinus is thin, membranous diploid and develops jointly from the basal upper surface (adaxial) of ovuliferous scale and outer layer of integument of the ovule.
Question
Pinus differs from mango in having [CBSE AIPMT 1993]
(a) tree habit
(b) green leaves
(c) ovules not enclosed in ovary
(d) wood
Answer/Explanation
Ans. (c)
Gymnosperms, (e.g. Pinus) are commonly called as naked seeded plants since their ovules (which later become seed) are not covered and lie naked on the surfaces of specialised leaves (megasporophylls or ovuliferous scales) arranged into cones.
Thus, gymnosperms are also known as seeded plants without flowers or phanerogams without ovary. In contrast, angiosperms are seed bearing, flowering vascular plants in which seeds are enclosed in fruits, and are called as phanerogams with ovary or seeded flowering plants.
Question
Which one is the most advanced from evolutionary view point? [CBSE AIPMT 1993]
(a) Selaginella
(b) Funaria
(c) Chlamydomonas
(d) Pinus
Answer/Explanation
Ans. (d)
From the evolutionary point of view, the given options can be arranged as Chlamydomonas, Funaria, Selaginella, and Pinus.
Pinus, i.e. gymnosperms are the most evolved seed bearing phanerogamic vascular sporophytic plants, after angiosperms (most advanced group of plants).
Pteridophytes (e.g. Selaginella) are spore bearing non-seeded vascular cryptogams. Algae, bryophytes and pteridophytes resemble each other in dependence on water for fertilisation.
Question
A plant having seeds but lacking flowers and fruits belongs to [CBSE AIPMT 1992]
(a) pteridophytes
(b) mosses
(c) ferns
(d) gymnosperms
Answer/Explanation
Ans. (d)
Gymnosperms (Gk Gymno=naked; sperma-seed) are commonly known as naked seed plants because their ovules (which later become seeds) are not covered and lie naked on the surfaces of specialised leaves called megasporophylls or ovuliferous scales, arranged into cones, flowers are absent; seed may have two, (e.g. Cycas)or more (e.g. Pinus)cotyledons.
Question
In Pinus, the pollen grain has 6 chromosomes then its endosperm will have the chromosome [CBSE AIPMT 1992]
(a) 12
(b) 18
(c) 6
(d) 24
Answer/Explanation
Ans. (c)
In gymnosperms (Pinus) both the pollen grains and endosperm are haploid structure, formed before fertilisation. If the pollen grain has haploid number of chromosome equal to 6 , then its endosperm will also have the same number of chromosome, i.e. 6 .
Question
Resin and terpentine are obtained from [CBSE AIPMT 1992]
(a) Cycas
(b) Pinus
(c) Cedrus
(d) Abies
Answer/Explanation
Ans. (b)
Pinus roxburghi is a source of resin and terpentine, obtained after distillation. Terpentine is utilised in varnishes and paints.
Question
In Pinus/gymnosperms, the haploid structure are [CBSE AIPMT 1989]
(a) megaspore, endosperm and embryo
(b) megaspore, pollen grain and endosperm
(c) megaspore, integument and root
(d) pollen grain, leaf and root
Answer/Explanation
Ans. (b)
In gymnosperms, the megaspore (haploid) is first cell of female gamet ophyte and undergoes repeated divisions to form a multicellular female gametophyte, which because of abundant food reserves, serves as endosperm. So, being produced before fertilisation, endosperm is haploid in gymnosperms.
Microspores or pollen grains are the first cell of the male gametophyte and are haploid in nature.
Question
In Pinus/Cycas/gymnosperms, the endosperm is [CBSE AIPMT 1988]
(a) triploid
(b) haploid
(c) diploid
(d) tetraploid
Answer/Explanation
Ans. (b)
In gymnosperms, e.g. Pinus, Cycas, endosperm develops before fertilisation and is haploid in nature. In angiosperms, endosperm is triploid (3n) and formed after double fertilisation.