Biology Class 11 NCERT Solutions: Chapter 3 Plant Kingdom Part 3 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Q: 8. Explain briefly the following terms with suitable examples:-

(i) Protonema

(ii) Antheridium

(iii) Archegonium

(iv) Diplontic

(v) Sporophyll

(vi) Isogamy

Answer:

(i) Protonema –

It is the first stage in the life cycle of a moss, developing directly from the spore. It consists of creeping, green, branched, and often filamentous structures.

(ii) Antheridium - It is the male sex organ present in bryophytes and pteridophytes and is surrounded by a jacket of sterile cells. It encloses the sperm mother cells, which give rise to the male gametes.

(iii) Archegonium - It is the female sex organ present in bryophytes, pteridophytes, and gymnosperms. In bryophytes and pteridophytes, it generally has a swollen venter and a tubular neck, and contains the female gamete called the egg.

(iv) Diplontic - It is the term used for the life cycles of seed-bearing plants (gymnosperms and angiosperms) . In these plants, the diploid sporophyte is dominant, photosynthetic, and independent. The gametophyte is represented by a single-celled (or a few-celled) structure.

(v) Sporophyll - In pteridophytes, the sporophytic plant body bears sporangia. These sporangia are subtended by leaf-like appendages known as sporophylls. In gymnosperms, microsporophylls and megasporophylls are found. These bear microspores and megaspores respectively.

(vi) Isogamy - It is a type of sexual reproduction involving the fusion of morphologically-similar gametes. This means that the gametes are of the same size, but perform different functions. This type of reproduction is commonly observed in Spirogyra.

Q: 9. Differentiate between the following:-

(i) Red algae and brown algae

(ii) liverworts and moss

(iii) Homosporous and heterosporous pteridophyte

(iv) Syngamy and triple fusion

Answer:

(i) Red algae and Brown algae

Q_9_i_Table of Red Algae and Brown Algae
Red algaeBrown algae
1Red algae are grouped under the

class Rhodophyceae.

1Brown algae are grouped under

the class Phaeophyceae.

2They contain Floridean starch as

stored food.

2They contain Mannitol or laminarin as stored food.
3They contain the photosynthetic pigments chlorophylls a and d, and phycoerythrin.3They contain the photosynthetic pigments chlorophylls a and c, and fucoxanthin.
4.Their cell walls are composed of cellulose, pectin, and phycocolloids.4.Their cell walls are composed of

cellulose and algin.

5.Flagella are absent5.Two flagella are present
6.
Image Showing the Red Algae
Image Showing the Brown Algae

(ii) Liverworts and Moss

Q_9_ii_Table of Liverworts and Moss
LiverwortsMoss
1They have unicellular rhizoids.1They have multicellular rhizoids.
2Scales are present very often2Scales are absent
3They are generally thalloid, with

dichotomous branching.

3They are foliage, with lateral branching.
4.Gemma cups are present4.Gemma cups are absent
5.Sporophyte has very little photosynthetic tissue5.Sporophyte has abundant

photosynthetic tissue

6.
Image Showing the Liverwort
6.
Image Showing the Moss

(iii) Homosporous and heterosporous pteridophyte

Q_9_iii_Table of Homosporous and Heterosporous Pteridophyte
Homosporous PteridophytesHeterosporous Pteridophyte
1They bear spores that are of the same type.1They bear two kinds of spores -

microspores and megaspores.

2They produce bisexual gametophytes.2They produce unisexual gametophytes.
The Life Cycle of Homosporous
The Life Cycle of Heterosporous
Homosporous and Heterosporous Pteridophyte

(iv) Syngamy and Triple fusion

Q_9_iv_Syngamy and Triple Fusion
SyngamyTriple fusion
1It is the process of fusion of the male gamete with the egg in an angiosperm.1It is the process of fusion of the male gamete with the diploid secondary nucleus in an angiosperm.
2A diploid zygote is formed as a result of Syngamy.2A triploid primary endosperm is formed as a result of triple fusion.

Q: 10. How would you distinguish monocots from dicots?

Answer:

Monocots and dicots can be differentiated through their morphological and anatomical characteristics.

Q_10_Table of Morphological and Anatomical Characteristics
CharacteristicMonocotDicot
Morphology
RootsFibrous RootsTap roots
VenationGenerally parallel venationGenerally reticulate venation
FlowersTrimerous flowersPentamerous flowers
Cotyledons in seedsOneTwo
Anatomy
No. of vascular bundles in stemNumerousGenerally 2 - 6
CambiumAbsentPresent
LeavesIsobilateral
Image Shows the Monocots
Dorsiventral
Image Shows the Dicots
Difference between Monocots and Dicots

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