Plant Kingdom Class 11 Biology Exam Questions

Exam Questions Class 11

Please refer to Plant Kingdom Class 11 Biology Exam Questions provided below. These questions and answers for Class 11 Biology have been designed based on the past trend of questions and important topics in your class 11 Biology books. You should go through all Class 11 Biology Important Questions provided by our teachers which will help you to get more marks in upcoming exams.

Class 11 Biology Exam Questions Plant Kingdom

Class 11 Biology students should read and understand the important questions and answers provided below for Plant Kingdom which will help them to understand all important and difficult topics.

Objective Type Questions

Question. The natural system of classification for flowering plants was given by
(a) Carolus Linnaeus
(b) Bentham and Hooker
(c) Engler and Prantl
(d) R. H. Whittaker

Answer

B

Question. Cytological information like chromosome number, structure, behaviour are related with
(a) numerical taxonomy
(b) cytotaxonomy
(c) chemotaxonomy
(d) all of these

Answer

B

Question. Fusion of two gametes which are dissimilar in size is termed as _______.
(a) isogamous
(b) oogamous
(c) anisogamous
(d) agamous

Answer

C

Question. Which of the following class of algae is rarely found in fresh water ?
(a) Chlorophyceae
(b) Phaeophyceae
(c) Rhodophyceae
(d) Both (a) and (b)

Answer

B

Question. What is the number and position of insertions of flagella in rhodopyceae class of algae ?
(a) 2 – 8, equal, apical
(b) 2, unequal, lateral
(c) 2 – 6, equal, lateral
(d) Flagella are absent in Rhodophyceae

Answer

D

Question. Which of the following groups of plants play an important role in plant succession on bare rocks/soil ?
(a) Algae
(b) Bryophytes
(c) Pteridophytes
(d) Gymnosperms

Answer

B

Question. In bryophytes, male and female sex organs are called ______ and ______ respectively.
(a) microsporangia; macrosporangia
(b) male strobili; female strobili
(c) antheridia; archegonia
(d) androecium; gynoecium

Answer

C

Question. Pyrenoids in green algal cells are related to
(a) starch formation
(b) protein storage
(c) general metabolism
(d) enzyme secretion

Answer

A

Question. Which of the following pteridophytes belong to class pteropsida?
(a) Equisetum and Psilotum
(b) Lycopodium and Adiantum
(c) Selaginella and Pteris
(d) Pteris and Adiantum

Answer

D

Question. Protonema and leafy stage are the predominant stage of the life cycle of
(a) moss
(b) dicots
(c) liverwort
(d) gymnosperm

Answer

A

Statement Type Questions

Question. Why rhodophyta exhibit a red colour ?
(a) Since most rhodophyta grow at great depths, the chlorophyll can only absorb light in the red area of
the spectrum.
(b) The wavelengths of light that are absorbed by chloro- phyll are passed to phycoerythrin (a red
pigment).
(c) Red pigment of rhodophyta absorbs all the light waves.
(d) The light reaching the greatest depth in water is in the blue-green region of the spectrum, is absorbed
by phycoerythrin.

Answer

B

Question. Which one of the following is the major difference between mosses and ferns ?
(a) Ferns lack alternation of generation while mosses show the same.
(b) Mosses are facultative aerobes while ferns are obligate aerobes.
(c) Vascular bundles of ferns show xylem vessels while those of mosses lack it.
(d) Sporophytes of ferns live much longer as compared to the sporophytes of mosses.

Answer

D

Question. Which one of the following terms is correctly matched with their definition in Pinus ?
(a) Monoecious – Male (microsporangiate) and female (megasporangiate) cones are produced on same
plant.
(b) Monoecious – Male and female sporophylls borne on same strobilus.
(c) Dioecious – Male and female cones are produced on different plants.
(d) Monoecious – Micro and megasporocarp develop on same plant.

Answer

A

Question. Which of the following statement(s) is/are correct ?
(a) In angiosperms, each embryo sac has a three-celled egg apparatus – one egg cell and two synergids,
three antipodal cells and two polar nuclei.
(b) All seed – bearing plants i.e., gymnosperms and angiosperms follow dipontic life patterns of plants.
(c) In gymosperms, roots in some genera have fungal association in the form of mycorrhiza (Pinus) while
in some others (Cycas) small specialized roots called coralloid are associated with N2 – fixing cyanobacteria.
(d) All of the above

Answer

D

Question. Which of the following statements is/are correct ?
(i) In Equisetum, the female gametophyte is retained on the parent sporophyte.
(ii) In Ginkgo, male gametophyte is not independent.
(iii) The sporophyte in Riccia is more developed than that in Polytrichum.
(iv) Sexual reproduction in Volvox is isogamous.
(a) Two
(b) Three
(c) Four
(d) One

Answer

A

Question. Which of the following statements with respect to algae are correct.
(i) Fusion between one large, non-motile female gamete and a smaller, motile male gamete is termed as
oogamous.
(ii) Fusion of two gametes dissimilar in size is termed as oogamous.
(iii) Fusion of two gametes similar in size is called anisogamous.
(iv) In chlorophyceae, the major pigments are chlorophyll a and b , and the food is stored as starch.
(v) In rhodophyceae, the major pigments are chlorophyll a and d , and the food is stored as mannitol.
(a) (i) and (v)
(b) (iii) and (v)
(c) (i) and (ii)
(d) (i) and (iv)

Answer

D

Question. Read the following statements and choose the correct option.
(i) In rhodophyceae, food is stored in the form of mannitol and laminarin.
(ii) The ovules of gymnosperms are not enclosed by ovary wall.
(iii) Salvinia is heterosporous.
(iv) In the diplontic life-cycle, the free living gametophyte represents the dominant phase.
(a) (ii) and (iii) are correct but (i) and (iv) are incorrect.
(b) (ii) and (iv) are correct but (i) and (iii) are incorrect.
(c) (iii) and (iv) are correct but (i) and (ii) are incorrect.
(d) (i) and (ii) are correct but (iii) and (iv) are incorrect.

Answer

A

Question. Which of the following statement(s) is/are correct?
(i) Green algae are the members of chlorophyceae.
(ii) Brown algae are found primarily in marine habitates
(iii) Some red algae are found in fresh water, mostly occur in salt water, some are found in brackish water.
(iv) The food in red algae is stored as floridean starch.
(v) Red alga may occur in both well-lighted regions close to water-surface and also at great depths in oceans where light penetration is little.
(a) (i) and (v) only
(b) (ii), (iii) and (iv) only
(c) All of the above
(d) None of the above

Answer

C

Question. Which of the following branch of science is being described by the given statements ?
(i) It can easily done by using computers based on all observable characters.
(ii) Numbers and codes are assigned to all the characters and the data are then processed.
(iii) Each character is given equal weightage and at the same time hundred of characters can be considered.
(a) Cytotaxonomy
(b) Numerical taxonomy
(c) Chemotaxonomy
(d) b-taxonomy

Answer

B

Question. The following statements are associated with one class of algae. Identify the class of algae.
(i) One or more storage bodies called pyrenoids located in the chloroplasts are present in the members of
this class.
(ii) They have a rigid cell wall made of an inner layer of cellulose and an outer layer of pectose.
(iii) Asexual reproduction is by flagellated zoospores produced in zoosporangia.
(iv) Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara are commonly found members of this class.
(a) Chlorophyceae
(b) Rhodophyceae
(c) Phaeophyceae
(d) None of these

Answer

A

Question. Which of the following group of plant is being described by the given statements ?
(i) The plant body is thalloid.
(ii) Asexual reproduction takes place by fragmentation of thalli, or by the formation of specialized structures called gemmae.
(iii) The sporophyte is differentiated into a foot, seta and capsule.
(iv) They grow usually in moist and shady habitats.
(a) Liverworts
(b) Moss
(c) Fern
(d) Gymnosperm

Answer

A

Question. Which of the following group of plant is being described by the given statements ?
(i) They are plants in which the ovules are not enclosed by any ovary wall and remain exposed before and
after fertilization.
(ii) The giant red wood tree Sequoia is one of the tallest tree species of the group.
(iii) The roots are generally tap roots.
(iv) They are heterosporous and they produce haploid microspores and megaspores.
(a) Algae
(b) Bryophytes
(c) Gymnosperms
(d) Pteridophytes

Answer

C

Question. Read the following statements and answer the question.
(i) Sporophytic generation is represented only by the one-celled zygote.
(ii) Meiosis in the zygote results in the formation of haploid spores.
(iii) The dominant, photosynthetic phase in such plants is free-living gametophyte.
(iv) Many algae such as Volvox, Spirogyra and some species of Chlamydomonas represent this pattern.
Which of the following pattern of life cycle of plant is described by the above statements ?
(a) Haplontic
(b) Diplontic
(c) Haplo-diplontic
(d) None of these

Answer

A

Question. Which of the following statements is incorrect?
(a) Pyrenoids contain protein besides starch.
(b) Sexual reproduction may be isogamous, oogamous and anisogamous in green and brown algae.
(c) Some of the members of algae also occur in association with fungi (lichen) and animals (eg, on
sloth bear).
(d) The leaves in pteridophytes are well adapted to withstand extremes of temperature, humidity and
wind.

Answer

D

Assertion/Reason Type Questions

In the following questions, a statement of Assertion is followed by a statement of Reason.
(a) If both Assertion and Reason are true and the Reason is the correct explanation of the Assertion.
(b) If both Assertion and Reason are true but the Reason is not the correct explanation of the Assertion.
(c) If assertion is true but Reason is false.
(d) If both Assertion and Reason are false.


Question. Assertion: Members of phaeophyceae vary in colour from olive green to various shades of brown.
Reason: Phaeophyceae possess chlorophyll a, c, carotenoids and xanthophylls.

Answer

A

Question. Assertion: Red algae contributes in producing coral reefs.
Reason: Some red algae secrete and deposit calcium carbonate over their walls.

Answer

A

Question. Assertion: Red algae contributes in producing coral reefs.
Reason: Some red algae secrete and deposit calcium carbonate over their walls.

Answer

A

Matching Type Questions

Question. Match the column-I with column-II and select the correct answer using the codes given below.

Column-I
(Group of Plant Kindgdom)
Column-II
(Examples)
A. Algae I. Solanum tuberosum
B. Fungi II. Equisetum
C. Angiosperm III. Cycas
D. Pteridophyte IV. Chlamydomonas
E. Gymnosperm V. Rhizopus

(a) A – V; B – IV; C – I; D – II; E – III
(b) A – IV; B – V; C – I; D – II; E – III
(c) A – IV; B – I; C – V; D – II; E – III
(d) A – IV; B – I; C – V; D – III; E – II

Answer

B

Question. Match column-I with column-II and choose the correct option.

Column-I Column-II
A. Phaeophyceae I. Have an elaborate mechanism of spore dispersal
B. Rhodophyceae II. first terrestrial plant with vascular tissue-phloem and xylem
C. Mosses III. Asexual reproduction by biflagellate zoosposes
D. PteridophytesIV. Polysiphonia, Porphyra, Gracilaria

(a) A – III; B – IV; C – I; D – II
(b) A – IV; B – III; C – I; D – II
(c) A – IV; B – III; C – II; D – I
(d) A – IV; B – I; C – III; D – II

Answer

A

Question. Match the column-I with column-II and choose the correct option.

Column-I
(System of classification)
Column-II
(Characteristics)
A. Artificial system of classification I. Based on few morphological characters
B. Natural system of classification II. Based on evolutionary relationships between the various organisms
C. Phylogenetic system of classification III. Based on natural affinities among the organisms and consider external as well as internal features.

(a) A – II; B – I; C – III
(b) A – I; B – III; C – II
(c) A – III; B – II; C – I
(d) A – I; B – II; C – III

Answer

B

Question. Match the column-I with column-II and choose the correct option.

Column-I Column-II
A. Amphibian of the plant kingdom I. Sphagnum
B. Specialized structures in liverworts for asexual reproduction II. Angiosperms
C. Monocotyledons and dicotyledons III. Bryophytes
D. A plant which has capacity to holding water IV. Gemmae

(a) A – III; B – IV; C – I; D – II
(b) A – III; B – IV; C – II; D – I
(c) A – IV; B – III; C – II; D – I
(d) A – III; B – II; C – IV; D – I

Answer

B

Question. Select the correct match of the feature present in column I with its respective terms given in column II.

Column-I
(features)
Column-II
(term)
A. Presence of tap roots and coralloid roots (I) Bryophyte
B. The synergids and antipodal cells degenerates after fertilization (II) Pteridophytes
C. The food is stored as floridean starch which is very similar to amylopectin and glycogen in structure (III) Red algae
D. Presence of sporophyte which is not free living but attached to the photosynthetic gametophytes and derives nourishment from it (IV) Angiosperms
E. Members of this group are used for medicinal purposes, as soil binders and frequently grown as ornamentals (V) Gymnosperms

(a) A – I; B – II; C – III; D – IV; E – V
(b) A – III; B – V; C – II; D – IV; E – I
(c) A – III; B – I; C – V; D – II ; E – IV
(d) A – V; B – IV; C – III; D – I; E – II

Answer

D

Diagram Type Questions

Question. Refer to the given figure (A, B, C and D) and answer the question. Which of the following figures are the members of green alga?

Plant Kingdom Class 11 Biology Exam Questions

(a) A, B and D
(b) A, B and C
(c) B, C and D
(d) C, D and A

Answer

A

Question. Which one of the following options correctly represents the type of life cycle patterns?

Plant Kingdom Class 11 Biology Exam Questions


(a) A – Diplontic, B – Haplodiplontic, C – Haplontic
(b) A – Haplodiplontic,B – Haplontic, C – Diplontic
(c) A – Haplontic, B – Diplontic, C – Haplodiplontic
(d) A – Diplontic, B – Haplontic, C – Haplodiplontic

Answer

D

Question. The given figure shows the life cycle of an angiosperm. Few plants are marked as A, B, C, D and E. Identify the correct labelling from the given options.

Plant Kingdom Class 11 Biology Exam Questions

(a) A–Stigma, B–Anther, C–Male gametophyte, D–Egg, E–Female gametophyte
(b) A–Stigma, B–Anther, C–Female gametophyte, D–Egg, E–Male gametophyte
(c) A–Stigma, B–Anther, C–Male gametophyte, D–Fertilized egg, E–Female gametophyte
(d) A–Stigma, B–Anther, C–Embryo sac, D–Egg, E–Female gametophyte

Answer

A

Critical Thinking Type Questions

Question. A bryophyte differs from pteridophytes in having
(a) archegonia.
(b) lack of vascular tissue.
(c) swimming antherozoids.
(d) independent gametophytes.

Answer

B

Question. The unique feature of bryophytes compared to other plant groups is that
(a) they produce spores.
(b) they lack vascular tissues.
(c) they lack roots.
(d) their sporophyte is attached to the gametophyte.

Answer

D

Question. Bryophytes are different from fungi in having
(a) land habit.
(b) sterile jacket layers.
(c) multiflagellate gametes.
(d) gametophytic plant body.

Answer

B

Question. If the cells of root in wheat plant have 42 chromosomes, then the no. of chromosome in the cell of pollen grain is
(a) 14
(b) 21
(c) 28
(d) 42

Answer

B

Question. Fruits are not formed in gymnosperms because of
(a) absence of pollination.
(b) absence of seed.
(c) absence of fertilization.
(d) absence of ovary.

Answer

D

Question. In angiosperms, a mature male gametophyte is derived from a pollen mother cell by
(a) three mitotic divisions.
(b) one meiotic and two mitotic divisions.
(c) two meiotic divisions.
(d) a single meiotic division.

Answer

B

Question. Protonema
(a) is a stage of gametophytic generation.
(b) is a creeping, green, branched and develops directly from a spore.
(c) produces lateral bud which forms leafy plant body.
(d) All of the above

Answer

A

Question. Classification of plants proposed by Carolus Linnaeus was artificial because it was based on
(a) only a few morphological characters.
(b) evolutionary tendencies which are diverse.
(c) anatomical characters which are adaptive in nature.
(d) physiological traits alongwith morphological characters.

Answer

A

Question. You are given an unknown plant to study in the laboratory.
You find that it has chlorophyll, no xylem. Its multicellullar sex organs are enclosed in a layer of jacket cells. Its gametophyte stage is free living. The plant probably belongs to
(a) chlorophyceae
(b) bryophyte
(c) pteridophyte
(d) gymnosperm

Answer

B

Question. Place the following groups of plants in order, beginning with those that first appeared on the earth and progressing toward those that appeared most recently in time.
(a) Gymnosperms, angiosperms, ferns, moss, algae
(b) Algae, moss, ferns, gymnosperms, angiosperms
(c) Moss, algae, ferns, angiosperms, gymnosperms
(d) Algae, ferns, angiosperms, gymnosperms, moss

Answer

B

Question. In order to colonize land, plants needed to acquire which of the following characteristics?
(a) A mechanism for moving water throughout the plant.
(b) A mechanism to prevent desiccation of tissues.
(c) An ability to screen ultraviolet radiation.
(d) Both (b) and (c)

Answer

D

Question. A universal feature of the life cycle of plants is
(a) morphologically identical haploid and diploid stages.
(b) genetically identical haploid and diploid stages.
(c) alteration of generations between heteromorphic haploid gametophytes and diploid sporophytes.
(d) none of the above

Answer

C

Question. A student was given a sample to observe under the microscope. He observed and found that the sample is the most common type of spore involved in asexual reproduction in algae. Identify the spore.
(a) Zoospore
(b) Endospore
(c) Hypnospore
(d) None of these

Answer

A

Very Short Answer Type Questions:

Question. The plant body in higher plants is well differentiated and well developed.
Roots are the organs used for the purpose of absorption. What is the equivalent of roots in the less developed lower plants?
Ans. Roots are represented by root like structure called rhizoids in less developed lower plants (bryophytes and pteridophytes). The plant tissue system in these is not differentiated into true leaf, stem and roots as it is found in higher plants (gymnosperm and angiosperm).

Question. Most algal genera show haplontic life style. Name an alga which is (a) Haplo diplontic (b) Diplontic
Ans. Haplo diplontic type of life cycle is exhibited by Ectocarpus, Polysiphonia and Kelps. Here, diploid saprophytic phase alternate with haploid gametophytic phase.
In Fucus, the main plant body is saprophytic and it shows diplontic type of life cycle.

Question. In bryophytes male and female sex organs are called ……… and ……… .
Ans. In bryophytes the male sex organ is antheridium and female sex organ is archegonium.
The gametophyte (n) in bryophyte bears the primiture sex organs in the form of antheridium (male) which produce flagellate antherozoids which are male gamete and need thin film of water to swim and reach female reproductive organ (archegonium).
Archegonia is female part which has single egg cell. Both these reproductive parts are born on male and female, anthridiophore and archegoniophores borne on haploid gametophyte.

Question. Food is stored as floridean starch in Rhodophyceae. Mannitol is the reserve food material of which group of algae?
Ans. The members of Phaeophyceae (brown algae) store mannitol as a reserve food material.

Question. Give an example of plants with
(a) haplontic life cycle
(b) diplontic life cycle
(c) haplo diplontic life cycle
Ans. (a) Haplontic life cycle It is exhibited by Volvox, Spirogyra and Chlamydomonas. The
dominant photosynthetic phase in these plants is gamotophytic phase which develops
from a haploid spores after a mitotic cell division of zygote.

Plant Kingdom Class 11 Biology Exam Questions

(b) Diplontic life cycle is found in gymnosperms and angiosperms. The dominant phase is diploid sporophyte plant develop from zygote.

Plant Kingdom Class 11 Biology Exam Questions

(c) Haplodiplontic life cycle It is an intermediate conditions exhibited by bryophytes and pteridophytes. Here haploid gametophytic stage alternates with diploid sporophytic stage.

Plant Kingdom Class 11 Biology Exam Questions

Short Answer Type Questions:

Question. Heterospory, i.e., formation of two types of spores—microspores and megaspores is a characteristic feature in the life cycle of a few members of pteridophytes and all spermatophytes. Do you think heterospory has some evolutionary significance in plant kingdom?
Ans. Heterospory is production of spores of two different sizes and sexes by the sporophytes of land plants. Two types of spores are produced by heterosporic plants.
Small spores are microspores which germinate into male gametophyte and large spores are macrospores which develop into female gametophyte.
In evolution of plants pteridophytes are intermediate between bryophytes and gymnosperms. All bryophytes are homosporous and all gymnosperms are heterosporous.
This condition is advanced as sexual dimorphism result in cross fertilisation.
Primitive or earlier pteridophytes are homosporous later pteriodophytes are heterosporous e.g., Dryopteris, Pteris-homosporous Selaginella, Salvinia-heterosporous.

Question. How far does Selaginella one of the few living members of Lycopodiales (pteridophytes) fall short of seed habit?
Ans. Seed habit The differentiation of spores into microspores and megaspores and their dependence on the parent sporophyte for the nutrition, are the certain features in the life cycle of Selaginella, which have been considered as the essential pre-requite for formation of seed, the characteristic of spermatophyte.
The evolution of heterospory and seed habits in Selaginella is evident by the following characters
(i) Reduction to a single functional megaspore per sporangium.
(ii) Retention and germination of megaspore within megasporangium
(iii) Development of protective layer and nutritive tissue called tapetum is present.
(iv) Development of embryosac with in the sporangium.
(v) Modification of distal end of mega sporangium to capture pollen grain.
(vi) Pollination and siphonogamy.
(vii) Temporary suspension of growth of embryo (dormancy period).

Question. Why are bryophytes called the amphibians of the plant kingdom?
Ans. Bryophytes are amphibian of plant kingdom. It is a group of primitive plant having a dominant gametophytic plant body. These plants can live in soil but depend on water for movement of male gametes called antherozoids to reach archegonium (female organ having egg cell) so that fertilisation can take place.

Question. The male and female reproductive organs of several pteridophytes and gymnosperms are comparable to floral structures of angiosperms. Make an attempt to compare the various reproductive parts of pteridophytes and gymnosperms with reproductive structures of angiosperms.
Ans. The structures are as given

Plant Kingdom Class 11 Biology Exam Questions

Question. How are the male and female gametophytes of pteridophytes and gymnosperms different from each other?
Ans. The male and female gametophytes of pteridophytes and gymnosperms different from each other are

Plant Kingdom Class 11 Biology Exam Questions

Question. In which plant will you look for mycorrhiza and corolloid roots? Also explain what these terms mean.
Ans. Mycorrhiza (Myco’s = fungus, rize = roots) is a symbiotic association between fungus and the roots of vascular plants. The fungus colonizes the roots of the host either intra or inter cellularly. It helps in the nutrient absorption from soil for the plant. Mycorrhizal associations are present in conifers, i.e., Pinus, Cedrus, Abies and Picea.
Coralloid roots is develop in Cycas. It is produced in clusters at the base of the stem and protrudes out over the ground. It is dichotomously branched and greenish in colour. It contains algal zone in cortex. This algal zone contains blue green algae like Anabaena and Nostoc which grow in symbiotic association with coralloid roots.

Question. Each plant or group of plants has some phylogenetic significance in relation to evolution Cycas, one of the few living members of gymnosperms is called as the ‘relic of past’. Can you establish a phylogenetic relationship of Cycas with any other group of plants that justifies the above statement?
Ans. Cycas as the relic of past Cycas is an evergreen plant which looks like a palm. It has unbranched stem and large compound leaf. It exhibit phylogenetic relationship with pteridophyte. Its evolutionary characters are
(i) Slow growth.
(ii) Shedding of seed when the embryo is still immature.
(iii) Little secondary growth and manoxylic wood.
(iv) Leaf like megasporophyllus.
(v) Flagellate sperms even when pollen tube is present.
(vi) Persistent leaf bases.
(vii) Circinate ptysix.
(viii) Arrangement of microsporangia is well defined archegonia.

Question. The heterosporous pteridophyte show certain characteristics, which are precursor to the seed habit in gymnosperms. Explain.
Ans. Heterospory, i.e., production of two types of spores smaller microspores and larger megaspore was first reported in Selaginella a pteridophyte. In Selaginella, the smaller microspores are destined to produce male gametophytes and the larger megaspores to female gametophyte.
The male gametophyte produces male gametes, whereas the female gametophyte produces archegonia and also provides nourishment to the developing embryo.
The phenomenon of heterospory, thus lead to the reduction of gametophyte, in situ germination of spores, retention of megagametophyte in the megasporangia and finally to the seed development. Thus, the heterospory in Selaginella forms the base for seed habit development in gymnosperms.

Question. Comment on the life cycle and nature of a fern prothallus.
Ans. The life cycle of fern (Dryopteris) clearly shows the alternation of generation. The gametophytic stage (n) alternates with the sporophytic stage (2n) figure given shows its complete life cycle.

Plant Kingdom Class 11 Biology Exam Questions

Prothallus The prothallus of the fern is multicellular, free living, thalloid, haploid and autotrophic structure. It develops from the spores produced by sporophyte after reduction division.
These spore germinate with a germtube with an apical cell and forms a filament of 3-6 cells and one or two rhizoids at the base which later develops into gametophytic plant.

Plant Kingdom Class 11 Biology Exam Questions

Long Answer Type Questions:

Question. Gametophyte is a dominant phase in the life cycle of a bryophyte. Explain.
Ans. Gametophyte is a haploid multicellular adult stage in a bryophyte’s life cycle. It bears male reproductive structure (antheridia) and female reproductive structure called archegonia, and thus produce haploid gametes antherozoids (male gamete) and egg cell (female gamete) respectively.
In mosses, liverworts and hornworts the gametophyte is a dominant form and thus most familiar phase of life cycle of the bryophyte. The moss gametophyte originate from a haploid spore. Initial phase of growth forms protonema in moss.
The protonema further develops into a main plant body of bryophyte which is thallus like prostrate and erect, attached to substratum by unicellular or multicellular rhizoids. They may possess root like, leaf like or stem like structures.

Question. Explain why sexual reproduction in angiosperms is said to take place through double fertilisation and triple fusion. Also draw a labelled diagram of embryo sac to explain the phenomena.
Ans. An angiospermic plants sexually reproduces by the formation of male and female gametes. The male gamete is a pollen which contain two male nuclei and female gamete is egg cell produced in ovule (female gametophyte).
The pollen grains germinate on the stigma of a flower and the resulting pollen tube grow through the tissues of stigma and style and reach near the egg apparatus. The two male gametes are discharged within the embryo sac. One of the male gamete fuses with the egg cell to form a diploid zygote.
This fusion is known as fertilisation or syngamy. The second male gamete fuses with the diploid secondary nucleus and forms the triploid Primary Endosperm Nucleus (PEN). This fusion is known as triple fusion.
Because of the involvement of two fusion, this event in angiosperms is termed as double fertilisation. The zygote then develops into embryo and PEN develops into endosperm which provides nourishment to the developing embryo.

Plant Kingdom Class 11 Biology Exam Questions

Question. Draw labelled diagrams of
(a) Female and male thallus of a liverwort.
(b) Gametophyte and sporophyte of Funaria.
(c) Alternation of generation in angiosperm.

Plant Kingdom Class 11 Biology Exam Questions
Plant Kingdom Class 11 Biology Exam Questions

Question. With the help of a schematic diagram describe the haplo diptontic life cycle pattern of a plant group.
Ans. Haplo diplontic life cycle (is also referred as diplohaplontic, diplo biontic or dibiontic) shows multicellular diploid and haploid stages as dipicted in the following figure.

Plant Kingdom Class 11 Biology Exam Questions


Life Cycle of a Pteridophyte The life cycle of a pteridophyte consists of two morphologically distinct phases
(i) The gametophytic phase
(ii) The sporophytic phase
These two phases come one after another in the life cycle of a pteridophyte. This phenomenon is called alternation of generation. The gametophyte is haploid with single set of chromosomes. It produces male sex organs antheridia and female sex organs archegonia.
(i) The antheridia may be embedded or projecting type. Each antheridium has single layered sterile jacket enclosing a mass of androcytes.
(ii) The androcytes are flask-shaped, sessile or shortly stalked and differentiated into globular venter and tubular neck.
(iii) The archegonium contains large egg, which is non-motile.
(iv) The antherozoids after liberation from antheridium, reaches up to the archegonium fuses with the egg and forms a diploid structure known as zygotes.
(v) The diploid zygote is the first cell of sporophytic generation. It is retained inside the archegonium and forms the embryo.
(vi) The embryo grows and develop to form sporophyte which is differentiated into roots, stem and leaves.
(vii) At maturity the plant bears sporangia, which encloses spore mother cells.
(viii) Each spore mother cell gives rise to four haploid spores which are usually arranged in tetrads.
(ix) The sporophytic generation ends with the production of spores.
(x) Each spore is the first cell of gametophytic generation. It germinates to produce gametophyte and completes its life cycle.

Question. Lichen is usually cited as an example of ‘symbiosis’ in plants where an algal and a fungal species live together for their mutual benefit. Which of the following will happen if algal and fungal partners are separated from each other?
(a) Both will survive and grow normally and independent from each other.
(b) Both will die
(c) Algal component will survive while the fungal component will die.
(d) Fungal component will survive while algal partner will die.
Based on your answer how do you justify this association as symbiosis?
Ans. (b) Is correct, lichen is a symbiotic association between an alga and a fungi, which live together for their mutual benefit. If both are separated from each other then they will die. The fungus holds water, provides protection and ideal housing to the alga.
The alga in turn supplies carbohydrate food for the fungus. If the alga is capable of fixing nitrogen (e.g., Nostoc), it supplies fixed nitrogen to the fungus.The kind of mutual interdependence helps lichens to grow on dry, barren rocks, where the other plants fail to exist. Morever, the algae or the fungi alone cannot grow in such places. Thus, both the partners cannot survive without each other.