Biology Class 11 NCERT Solutions: Chapter 3 Plant Kingdom Part 3

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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
Q_9_i_Table of Red Algae and Brown Algae

Red algae

Brown algae

1

Red algae are grouped under the

class Rhodophyceae.

1

Brown algae are grouped under

the class Phaeophyceae.

2

They contain Floridean starch as

stored food.

2

They contain Mannitol or laminarin as stored food.

3

They contain the photosynthetic pigments chlorophylls a and d, and phycoerythrin.

3

They 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 absent

5.

Two flagella are present

6.

Image showing the Red algae

Image Showing the Red Algae

Image showing the Red algae

Image showing the Brown algae

Image Showing the Brown Algae

Image showing the Brown algae

(ii) Liverworts and Moss

Q_9_ii_Table of Liverworts and Moss
Q_9_ii_Table of Liverworts and Moss

Liverworts

Moss

1

They have unicellular rhizoids.

1

They have multicellular rhizoids.

2

Scales are present very often

2

Scales are absent

3

They are generally thalloid, with

dichotomous branching.

3

They are foliage, with lateral branching.

4.

Gemma cups are present

4.

Gemma cups are absent

5.

Sporophyte has very little photosynthetic tissue

5.

Sporophyte has abundant

photosynthetic tissue

6.

Image showing the Liverwort

Image Showing the Liverwort

Image showing the Liverwort

6.

Image showing the Moss

Image Showing the Moss

Image showing the Moss

(iii) Homosporous and heterosporous pteridophyte

Q_9_iii_Table of Homosporous and Heterosporous Pteridophyte
Q_9_iii_Table of Homosporous and Heterosporous Pteridophyte

Homosporous Pteridophytes

Heterosporous Pteridophyte

1

They bear spores that are of the same type.

1

They bear two kinds of spores -

microspores and megaspores.

2

They produce bisexual gametophytes.

2

They produce unisexual gametophytes.

Image of the life cycle of homosporous

Image of the Life Cycle of Homosporous

Image of the life cycle of homosporous

Image of the life cycle of heterosporous

Image of the Life Cycle of Heterosporous

Image of the life cycle of heterosporous

Homosporous and heterosporous pteridophyte

Homosporous and Heterosporous Pteridophyte

Homosporous and heterosporous pteridophyte

(iv) Syngamy and Triple fusion

Q_9_iv_Syngamy and Triple Fusion
Q_9_iv_Syngamy and Triple Fusion

Syngamy

Triple fusion

1

It is the process of fusion of the male gamete with the egg in an angiosperm.

1

It is the process of fusion of the male gamete with the diploid secondary nucleus in an angiosperm.

2

A diploid zygote is formed as a result of Syngamy.

2

A 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
Q_10_Table of Morphological and Anatomical Characteristics

Characteristic

Monocot

Dicot

Morphology

Roots

Fibrous Roots

Tap roots

Venation

Generally parallel venation

Generally reticulate venation

Flowers

Trimerous flowers

Pentamerous flowers

Cotyledons in seeds

One

Two

Anatomy

No. of vascular bundles in stem

Numerous

Generally 2-6

Cambium

Absent

Present

Leaves

Isobilateral

Image shows the Monocots

Image Shows the Monocots

Image shows the Monocots

Dorsiventral

Image shows the Dicots

Image Shows the Dicots

Image shows the Dicots

Difference between Monocots and dicots

Difference between Monocots and Dicots

Difference between Monocots and dicots