This chapter contains many technical terms and specific examples that are vital for scoring well. These solutions provide the most accurate, NCERT-aligned descriptions of plant structures and life cycles.
NEET frequently asks questions about the life cycles of specific plants and the economic importance of algae. These solutions provide the exact points and terminology required to correctly answer these high-weightage questions.
Yes, they are fully updated for the current curriculum. They are useful because they focus on the comparative study of plant groups, making it easier for students to remember the distinguishing features and examples of each division.
Join ALLEN!
(Session 2026 - 27)
Choose class
Choose your goal
Preferred Mode
Choose State
NCERT Solutions Class 11 Biology Chapter 3 - Plant Kingdom
NCERT Solutions for Class 11 Biology Chapter 3 (Plant Kingdom) offer a deep dive into the diverse world of multicellular eukaryotic photoautotrophs. This chapter transitions from the general classification of life to a detailed study of the plant world, covering the evolutionary journey from simple Algae to the complex Angiosperms that dominate our landscape today.
NCERT Solutions for Class 11 Biology Chapter 3 by ALLEN are crafted by expert faculty to simplify the complex life cycles and reproductive strategies of plants. The solutions focus on key evolutionary milestones, such as the development of vascular tissues and the shift from gametophyte-dominant to sporophyte-dominant life cycles.
Mastering this chapter is vital for NEET aspirants, as it is a core part of the "Diversity in Living Organisms" unit. These solutions provide the conceptual clarity needed to distinguish between liverworts and mosses, understand the importance of heterospory in Pteridophytes, and visualize the unique double fertilization process in Angiosperms.
What is the basis of classification of algae?
Ans. Algae are classified mainly on the basis of:
Pigments present in their cells.
Stored food material.
Number of flagella and their position.
Cell wall composition.
Mode of reproduction.
On the basis of these features, algae are classified into three main classes: Chlorophyceae (green algae), Phaeophyceae (brown algae) and Rhodophyceae (red algae).
When and where does reduction division take place in the life cycle of a liverwort, a moss, a fern, a gymnosperm and an angiosperm?
Ans.Plant group :
When and where reduction division occurs.
Liverwort :
During spore formation in the capsule of sporophyte.
Moss :
During spore formation in the capsule of sporophyte,
Fern :
During spore formation in the sporangia.
Gymnosperm :
During formation of microspores and megaspores in microsporangia and megasporangia.
Angiosperm :
During formation of microspores and megaspores in anthers and ovules.
Thus, meiosis or reduction division generally occurs during spore formation in these plants.
Name three groups of plants that bear archegonia. Briefly describe the life cycle of any one of them.
Ans. Three groups of plants that bear archegonia are:
(1) Bryophytes
(2) Pteridophytes
(3) Gymnosperms
Life cycle of a fern
The dominant phase in a fern is the sporophytic phase. The sporophyte produces spores in sporangia, which are generally borne on sporophylls. Meiosis in spore mother cells produces haploid spores. The spores germinate to form a small, multicellular, free-living, photosynthetic prothallus, which represents the gametophytic phase.
The prothallus bears antheridia and archegonia. The male and female gametes fuse to form a diploid zygote. The zygote develops into an embryo and subsequently into a young sporophyte.
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.
Ans. • Protonemal cell of a moss - haploid.
Primary endosperm nucleus in dicot - triploid.
Leaf cell of a moss - haploid.
Prothallus cell of a fern - haploid.
Gemma cell in Marchantia - haploid.
Meristem cell of monocot - diploid.
Ovum of a liverwort - haploid.
Zygote of a fern - diploid.
Write a note on economic importance of algae and gymnosperms.
Ans.
A. Economic importance of algae :
Algae are used as food. Species of Porphyra,Laminaria and Sargassum are used as food.
Some marine algae are rich in iodine, potassium and other minerals.
Agar is obtained from Gelidium and Gracilaria and is used in culture media and food industries.
Algin is obtained from brown algae and is used commercially.
Carrageen is obtained from red algae and has commercial importance.
Algae contribute significantly to oxygen production and form the primary producers in aquatic ecosystems.
B. Economic importance of gymnosperms :
Gymnosperms are important sources of wood.
Wood from Pinus, Cedrus and other conifers is used for construction and furniture.
Resins and turpentine are obtained from conifers. Ephedrine, obtained from Ephedra, is used medicinally.
Cycas and Pinus are also grown as ornamental plants.
Both gymnosperms and angiosperms bear seeds, then why are they classified separately?
Ans. Gymnosperms and angiosperms both bear seeds but they are classified separately because gymnosperms are a group of plants in which the ovules are freely exposed on open megasporophylls, whereas in angiosperms the seeds or ovules are enclosed within ovary which later forms the fruit.
What is heterospory? Briefly comment on its significance. Give two examples.
Ans.Heterospory : The occurrence of two kinds of spores in the same plant is called as heterospory. Among them the smaller spore is called microspore and the larger spore is called megaspore. Heterospory first evolved in pteridophytes. Significance of heterospory.
(i) Heterospory is associated with the sexual differentiation of gametophyte a microspore develops into a male gametophyte whereas a megaspore develops into a female gametophyte.
(ii) In homosporous pteridophytes spores have to germinate on soil thus face more environmental problems. In heterosporous pteridophytes, spores germinate within the sporangium and the gametophytes are retained inside for variable periods of time. Hence, germinating gametophyte has better chances of survival. This lays the foundation of complete retention of gametophytes within sporophytes in angiosperms and gymnosperms.
(iii) Heterospory is the basis of development of seed habit in higher plants.
Explain briefly thefollowing terms with suitable examples.
(i) Protonema : Protonema is the green, branched and filamentous structure produced from a moss spore. It represents the first stage of the gametophytic phase.
Example: Funaria
(ii) Antheridium : Antheridium is the male sex organ that produces male gametes or antherozoids.
Example: Antheridia occur in mosses and ferns.
(iii) Archegonium : Archegonium is the female sex organ that produces the egg or ovum.
Example: It occurs in bryophytes, pteridophytes and gymnosperms.
(iv) Diplontic : In a diplontic life cycle, the diploid sporophyte is the dominant, independent phase, while the gametophytic phase is highly reduced.
Example: Gymnosperms and angiosperms.
(v) Sporophyll : A sporophyll is a leaf-like structure that bears sporangia.
Example: Fern sporophylls bear sporangia.
(vi) Isogamy : Isogamy is the fusion of morphologically similar gametes.
Example: Ulothrix and Spirogyra.
Differentiate between the following:
(i) Red algae and brown algae
(ii) Homosporous and heterosporous pteridophytes
(iii) Liverworts and moss
(iv) Syngamy and triple fusion.
Ans.
(i) The differences between red algae and brown algae are as follows :
Red algae
Brown algae
(i)
The major pigment of red algae are chlorophyll a, d and phycoerythrin.
The major pigment of brown algae are chlorophyll a, c and fucoxanthin.
(ii)
In red algae, floridean starch is the stored food material.
In brown algae, mannitol and laminarin are the stored food materials.
(iii)
In red algae cellulose is present in cell wall.
In brown algae cellulose and algin are present in cell wall.
(iv)
Flagella are absent.
The number of flagella is 2, they are unequal in size and lateral in position.
(v)
Thylakoids are unstaked.
Thylakoids occur in groups of three.
(ii) The differences between homosporous and heterosporous pteridophytes are as follows:
Homosporous pteridophytes
Heterosporous pteridophytes
(i)
In these pteridophytes only one kind of spore is produced.
In these pteridophytes two kinds of spores are produced.
(ii)
The spores are equal in size.
The smaller spores are called microspores and the larger spores are called megaspores.
(iii)
The spores are produced from the same sporangia.
The microspores are produced from the microsporangia and the megaspores are produced from the megasporangia.
(iv)
The spores develop one kind of gametophyte.
The microspore develops into male gametophyte whereas the megaspore develops into female gametophyte.
(v)
Spores germinate in soil and produce independent gametophyte.
Spores germinte within sporangia and produce dependent gametophyte.
(vi)
e.g., Lycopodium
e.g., Selaginella, Salvinia.
(iii) The differences between liverworts and mosses are as follows :
Liverworts
Mosses
(i)
The gametophytic plant body may be thallose (e.g., Riccia) or foliose.
Gametophytic plant body is differentiated into prostrate, branched filamentous, thalloid protonema and leafy erect gametophore.
(ii)
On the ventral surface of the thallus unicellular rhizoids and simple multicellular scales are present.
The rhizoids are multicellular, branched with oblique septa.
(iii)
Sex organs are present on dorsal surface of the thallus and develop from superficial cells.
The sex organs develop from the superficial cells at the apex of leafy gametophyte.
(iv)
Elaters are generally present but absent in Riccia.
Elaters are absent.
(v)
Stomata are absent in the wall of the capsule.
Stomata are present in sporophyte for gaseous exchange.
(vi)
Dehiscence of capsule is irregular.
Dehiscence is regular.
(iv) The differences between syngamy and triple fusion are as follows :
Syngamy
Triple fusion
(i)
It is the generative fertilisation.
It is vegetative fertilisation.
(ii)
Both male and female gametes are involved in syngamy.
It produces a triploid primary endosperm cell.
(iii)
Syngamy produces a diploid zygote.
It produces a triploid primary endosperm cell.
(iv)
Zygote forms the embryo.
Primary endosperm cell produces a food laden endosperm.
Match the following (Column I with Column II).
Column-I
Column-II
(a)
Chlamydomonas
(i)
Moss
(b)
Cycas
(ii)
Pteridophyte
(c)
Selagmella
(iii)
Algae
(d)
Sphagnum
(iv)
Gymnosperm
Ans.
Chlamydomonas
- Algae
Cycas
- Gymnosperm
Selayinella
- Pteridophyte
Sphagnum
- Moss
Describe the important characteristics of gymnosperms.
Ans. Important characteristics of gymnosperms are :
Gymnosperms are heterosporous, producing two kinds of spores-microspores and megaspores.
The plants are perennial and evergreen, woody trees or shrubs.
The roots are generally tap roots.
Leaves may be simple or compound. In Cycas, leaves are large and pinnate, whereas in Pinus they are needle-like.
Gymnosperms bear cones or strobili.
Male cones produce microspores and female cones bear megasporophylls with ovules.
The ovules are not enclosed by any ovary wall and are therefore naked.
The male and female gametophytes are highly reduced.
The male gametophyte produces pollen grains. Pollination is generally carried out by wind. Fertilisation takes place within the archegonium.
The seeds produced are naked, because they are not enclosed within fruits. Examples include Cycas, Pinus and Cedrus.
3.0Key Features of NCERT Solutions for Class 11 Biology Chapter 3
Comparative Pigment Analysis: The solutions provide clear tables comparing the three classes of Algae based on their major pigments (Chlorophyll a, b, c, d), stored food (Starch, Mannitol, Floridean starch), and cell wall composition.
Evolutionary Milestone Focus: Detailed explanations on why Bryophytes are called "amphibians" and how Pteridophytes marked the beginning of vascularization on Earth.
Gymnosperm vs. Angiosperm Distinction: Step-by-step breakdown of the differences in reproductive structures, such as the absence of vessels in xylem (mostly) and the nature of the endosperm.
Life Cycle Clarity: Expert guidance on understanding "Alternation of Generations," explaining how the haploid gametophyte and diploid sporophyte stages vary in dominance across plant groups.
Prepared by Expert Faculty: Prepared by ALLEN subject experts, these solutions ensure botanical accuracy and strict alignment with the latest NEET and NCERT patterns.
Economic Importance Highlights: Summary of the uses of plants, such as Agar from Gelidium, Algin from brown algae, and the role of Sphagnum in peat formation.