NCERT Class 11 Biology Plant Kingdom

Read and download NCERT Class 11 Biology Plant Kingdom in NCERT book for Class 11 Biology. You can download latest NCERT eBooks chapter wise in PDF format free from Studiestoday.com. This Biology textbook for Class 11 is designed by NCERT and is very useful for students. Please also refer to the NCERT solutions for Class 11 Biology to understand the answers of the exercise questions given at the end of this chapter

NCERT Book for Class 11 Biology Chapter 3 Plant Kingdom

Class 11 Biology students should refer to the following NCERT Book Chapter 3 Plant Kingdom in Class 11. This NCERT Book for Class 11 Biology will be very useful for exams and help you to score good marks

Chapter 3 Plant Kingdom NCERT Book Class 11

PLANT KINGDOM

3.1 ALGAE

Algae are chlorophyll-bearing, simple, thalloid, autotrophic and largely aquatic (both fresh water and marine) organisms. They occur in a variety of other habitats: moist stones, soils and wood. Some of them also occur in association with fungi (lichen) and animals (e.g., on sloth bear). The form and size of algae is highly variable (Figure 3.1). The size ranges from the microscopic unicellular forms like Chlamydomonas, to colonial forms like Volvox and to the filamentous forms like Ulothrix and Spirogyra. A few of the marine forms such as kelps, form massive plant bodies.

The algae reproduce by vegetative, asexual and sexual methods. Vegetative reproduction is by fragmentation. Each fragment develops into a thallus. Asexual reproduction is by the production of different types of spores, the most common being the zoospores. They are flagellated (motile) and on germination gives rise to new plants. Sexual reproduction takes place through fusion of two gametes. These gametes can be flagellated and similar in size (as in Chlamydomonas) or non-flagellated (non-motile) but similar in size (as in Spirogyra). Such reproduction is called isogamous. Fusion of two gametes dissimilar in size, as in some species of Chlamydomonas is termed as anisogamous. Fusion between one large, non-motile (static) female gamete and a smaller, motile male gamete is termed oogamous, e.g., Volvox, Fucus. Algae are useful to man in a variety of ways. At least a half of the total carbon dioxide fixation on earth is carried out by algae through photosynthesis. Being photosynthetic they increase the level of dissolved oxygen in their immediate environment. They are of paramount importance as primary producers of energy-rich compounds which form the basis of the food cycles of all aquatic animals. Many species of Porphyra, Laminaria and Sargassum are among the 70 species of marine algae used as food. Certain marine brown and red algae produce large amounts of hydrocolloids (water holding substances), e.g., algin (brown algae) and carrageen (red algae) are used commercially. Agar, one of the commercial products obtained from Gelidium and Gracilaria are used to grow microbes and in preparations of ice-creams and jellies. Chlorella and Spirullina are unicellular algae, rich in proteins and are used as food supplements even by space travellers. The algae are divided into three main classes: Chlorophyceae, Phaeophyceae and Rhodophyceae.

3.1.1 Chlorophyceae

The members of chlorophyceae are commonly called green algae. The plant body may be unicellular, colonial or filamentous. They are usually grass green due to the dominance of pigments chlorophyll a and b. The pigments are localised in definite chloroplasts. The chloroplasts may be discoid, plate-like, reticulate, cup-shaped, spiral or ribbon-shaped in different species. Most of the members have one or more storage bodies called pyrenoids located in the chloroplasts. Pyrenoids contain protein besides starch. Some algae may store food in the form of oil droplets. Green algae usually have a rigid cell wall made of an inner layer of cellulose and an outer layer of pectose.

Vegetative reproduction usually takes place by fragmentation or by formation of different types of spores. Asexual reproduction is by flagellated zoospores produced in zoosporangia. The sexual reproduction shows considerable variation in the type and formation of sex cells and it may be isogamous, anisogamous or oogamous. Some commonly found green algae are: Chlamydomonas, Volvox, Ulothrix, Spirogyra and Chara (Figure 3.1a).

EXERCISES

1. What is the basis of classification of algae?

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

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

4. 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 ferm; gemma cell in Marchantia; meristem cell of monocot, ovum of a liverwort, and zygote of a fern.

5. Write a note on economic importance of algae and gymnosperms.

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

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

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

(i) protonema

(ii) antheridium

(iii) archegonium

(iv) diplontic

(v) sporophyll

(vi) isogamy

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

10. How would you distinguish monocots from dicots?

11. 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

12. Describe the important characteristics of gymnosperms.


Please refer to attached file for NCERT Class 11 Biology -  Plant Kingdom

Chapter 17 Breathing and Exchange of Gases
NCERT Class 11 Biology Breathing and Exchange of Gases

NCERT Book Class 11 Biology Chapter 3 Plant Kingdom

The above NCERT Books for Class 11 Biology Chapter 3 Plant Kingdom have been published by NCERT for latest academic session. The textbook by NCERT for Chapter 3 Plant Kingdom Biology Class 11 is being used by various schools and almost all education boards in India. Teachers have always recommended students to refer to Chapter 3 Plant Kingdom NCERT etextbooks as the exams for Class 11 Biology are always asked as per the syllabus defined in these ebooks. These Class 11 Chapter 3 Plant Kingdom book for Biology also includes collection of question. Along with Biology Class 11 NCERT Book in Pdf for Chapter 3 Plant Kingdom we have provided all NCERT Books in English Medium for Class 11 which will be really helpful for students who have opted for english language as a medium. Class 11 students will need their books in English so we have provided them here for all subjects in Class 11.

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