NCERT Solutions for Class 11 Biology Chapter 3

Plant Kingdom Class 11

Chapter 3 Plant Kingdom Exercise Solutions

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Exercise : Solutions of Questions on Page Number : 44

Q1 :  

What is the basis of classification of algae?


Answer :

Algae are classified into three main classes - Chlorophyceae, Phaeophyceae, and Rhodophyceae. These divisions are based on the following factors:

(a) Major photosynthetic pigments present

(b) Form of stored food

(c) Cell wall composition

(d) Number of flagella and position of insertion

Class I - Chlorophyceae

Common name - Green algae

Major pigments - Chlorophylls a and b

Stored food - Starch

Cell wall composition - Cellulose

Flagella number and position - 2-8; equal and apical

Class II - Phaeophyceae

Common name- Brown algae

Major pigments - Chlorophylls a and c, and fucoxanthin

Stored food - Mannitol and laminarin

Cell wall composition - Cellulose and algin

Flagella number and position - 2; unequal and lateral

Class III­ - Rhodophyceae

Common name - Red algae

Major pigments - Chlorophylls a and b, and phycoerythrin

Stored food -­ Floridean starch

Cell wall - Cellulose, pectin, and polysulphate esters

Flagella number - Absent

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Q2 :  

When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm?


Answer :

Liverwort- In liverworts, the main plant-body is haploid (gametophytic). It bears the male and female sex organs which produce gametes. These gametes fuse to form a zygote. The zygote develops on the gametophytic plant-body to form a sporophyte. The sporophyte is differentiated into the foot, seta, and capsule. Many haploid spores are produced as a result of the reduction division taking place inside the capsule.

Moss- In mosses, the primary protonema (developed in the first stage) develops into the secondary protonema. Both these stages are haploid or gametophytic. The secondary protonema bears the sex organs which produce gametes. These gametes fuse to form a zygote. The zygote develops into a sporophyte. Many spores are formed as a result of the reduction division taking place in the capsule of this sporophyte.

Fern- In ferns, the main plant-body is sporophytic. Its leaves are known as sporophylls and these bear the sporangia. Reduction division takes place in these sporangia, thereby producing many spores.

Gymnosperm- In gymnosperms, the main plant-body is sporophytic. They bear two types of leaves - microsporophylls and megasporophylls. Reduction division takes place in the microsporangia present on the microsporophylls (producing pollen grains) and on the megasporangia present on the megasporophylls (producing megaspores).

Angiosperm- In angiosperms, the main plant-body is sporophytic and bears flowers. The male sex organ in the flower is the stamen, while the female sex organ is the pistil. Reduction division takes place in the anthers of the stamen (producing haploid pollen grains) and in the ovary of the pistil (producing eggs).

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Q3 :  

Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them.


Answer :

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Q4 :  

Mention the ploidy of the following: protonemal cell of a moss; primary endosperm nucleus in dicot, leaf cell of a moss; prothallus cell of a fern; gemma cell in Marchantia; meristem cell of monocot, ovum of a liverwort, and zygote of a fern.


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Q5 :  

Write a note on economic importance of algae and gymnosperms.


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Q6 :  

Both gymnosperms and angiosperms bear seeds, then why are they classified separately?


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Q7 :  

What is heterospory? Briefly comment on its significance. Give two examples.


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Q8 :  

Explain briefly the following terms with suitable examples:-

(i) protonema

(ii) antheridium

(iii) archegonium

(iv) diplontic

(v) sporophyll

(vi) isogamy


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Q9 :  

Differentiate between the following:-

(i)red algae and brown algae

(ii) liverworts and moss

(iii) homosporous and heterosporous pteridophyte

(iv) syngamy and triple fusion


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Q10 :  

How would you distinguish monocots from dicots?


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Q11 :  

Match the followings (column I with column II)

Column I

Column II

(a)

Chlamydomonas

(i)

Moss

(b)

Cycas

(ii)

Pteridophyte

(c)

Selaginella

(iii)

Algae

(d)

Sphagnum

(iv)

Gymnosperm


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Q12 :  

Describe the important characteristics of gymnosperms.


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<< Previous Chapter 2 : Biological Classification Next Chapter 4 : Animal Kingdom >>

Biology : CBSE NCERT Exercise Solutions for Class 11th for Plant Kingdom will be available online in PDF book form soon. The solutions are absolutely Free. Soon you will be able to download the solutions.

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