Plant Kingdom Class 11 Important Questions and Answers

Plant Kingdom Class 11 Important Questions and Answers are given in this article for preparation purposes. The questions include the concepts of Angiosperms, gymnosperms, and various other plants.

Plant kingdom is a universe of different varieties of plants. They include algae, bryophyte, pteridophyte, gymnosperm and angiosperm on the basis of different characteristics. Algae are photosynthetic, simple, and thalloid aquatic organisms such as Porphyra, Volvox and Ulothrix etc. Bryophytes (Liverworts and Mosses) are more differentiated than algae as they have root, stem, and root-like structures. Pteridophytes (Selaginella, Equisetum, etc.) have well-differentiated vascular tissues.

Gymnosperms include Pinus and Cycas and their ovules are not enclosed by the ovary wall whereas Angiosperm (sunflower, beans, etc.) seeds are enclosed by the ovary wall and possess double fertilization. Different plant groups show different life cycle patterns including haplontic, diplontic or intermediate.

Plant Kingdom

Read More: Fertilization in Plants

Plant Kingdom Class 11 Important Questions and Answers

Very Short Answer Questions (1 Mark Questions)

Ques. Which red algae is used as a vegetable?

Ans. Porphyra, red algae, are used as vegetables.

Ques. How pteridophytes are different from liverworts?

Ans. Liverworts (Marchantia) are bryophytes that have gametophytes as the main plant body. However, pteridophytes (Pinus) have sporophytes as the main plant body.

Ques. Name the plants which produce seeds but no flowers or seeds?

Ans. Pteridophytes produce spores but no flowers or seeds.

Ques. What are two classes of bryophytes?

Ans. Mosses and Liverworts are two classes of bryophytes.

Ques. Why Bryophytes are known as amphibians of the plant kingdom?

Ans. Bryophytes are known as amphibians of the plant kingdom as they live on land but require water for the transfer of male gamete into the female sex organ for fertilization.

Read More: Difference between Bryophytes and Pteridophytes

Ques. Give one example of unicellular algae.

Ans. Chlamydomonas is a unicellular alga.

Ques. Liverworts are bryophytes. Give reason.

Ans. Bryophytes that appear like liver are called liverworts. For example- Marchantia.

Ques. Define heterosporous pteridophyte.

Ans. Homosporous pteridophytes produce two different types of spores, macro (large) and micro (small). For example-Selaginella, Salvinia etc.

Read More: Spore Formation

Ques. Define homosporous pteridophyte.

Ans. Homosporous pteridophytes produce similar types of spores. For example-Dryopteris etc.

Short Answer Questions (2 Marks Questions)

Ques. Define cryptogams?

Ans. The plants that reproduce by spores without flowers or seeds are called cryptogams. They include- Thallophyta (algae), Bryophyta (liverworts and mosses) and Pteridophyta (Pinus and Cycas).

Ques. Discuss the significance of capsules in mosses.

Ans. The sporophyte in mosses consists of a foot, seta and capsule. Example-Funaria, Polytrichum and Sphagnum. The capsule consists of spores that are formed after meiosis. When it ripens, its dehiscence releases spores take place and spores that are taken away by winds. The spores develop favourable conditions into protonema.

Ques. What is triple fusion?

Ans. Triple fusion is the characteristic feature of angiosperms. It involves the fusion of the secondary nucleus (diploid/2n) with one male gamete (n). Both diploid and haploid nucleus combines, and this is known as triple fusion. This forms a primary endosperm nucleus which further develops into endosperm. This endosperm provides nutrition to the developing zygote.

Read More: Double Fertilization in Angiosperms

Ques. How gymnosperms differ from bryophytes and pteridophytes in terms of gametophytes?

Ans. In bryophytes and pteridophytes, the gametophytes have free-living existence whereas in gymnosperms they do not have an independent free-life existence.

Ques. Why Bryophytes are known as pioneers of ecological succession?

Ans.- Bryophytes play an important role in plant succession. They grow on bare rocks and secrete organic acids. These acids degrade the rocks gradually and convert rock into soil by the process of weathering. Then other plants start growing in the soil and increase their number. Thus, they are pioneers in primary plant succession.

Kingdom Plantae

Long Answer Questions (3 Marks Question)

Ques. Differentiate dioecious and monoecious plants.

Ans. The differences between monoecious and dioecious plants are as follows:

Read More: Sexual Reproduction in Flowering Plants

Ques. What are the commercial uses of algae?

Ans.- The commercial uses of algae are as follows-

1. Algae such as Gelidium and Gracilaria are used to grow microbes.
2. They are used in the preparations of ice-creams and jellies.
3. Chlorella is rich in proteins and is used as a food supplement by space travellers.
4. Many species of Laminaria and Sargassum marine algae are used as food.

Ques. Describe different types of gametes in algae.

Ans. In algae, sexual reproduction takes place by the fusion of two gametes. These gametes may vary in their size. If gametes are similar in size (as in Spirogyra), such reproduction is called isogamous. If two gametes are dissimilar in size, as in species of Eudorina is termed anisogamous. If there is one large and one smaller gamete fusion, then it is termed oogamous, e.g., Volvox, Fucus.

Ques. Write three differences between Chlorophyceae, Phaeophyceae and Rhodophyceae.

Ans. The differences are as follows:

Ques. How gymnosperm can tolerate extreme environments?

Ans. Gymnosperms or conifers are adapted to tolerate extreme temperatures like snow, high temperature. Following are the reasons-

1. Thick cuticle- The cuticle forms a thick protective layer in the whole plant and reduces water loss in extremely high temperatures.
2. Sunken stomata- The surface area of stomata reduces which minimizes the water loss.
3. Needle-like leaves- Their needle-like leaves have very less surface area as compared to broadleaf. Thus, minimum the surface area minimum will be the loss of water. Also, snow slips away from the needle-like leaves and protects the plant from cold.

Ques. Describe gametophyte in bryophyte and pteridophyte.

Ans. Gametophyte in bryophyte has a protonemal and leafy stage. The first stage is the protonema stage, which develops directly from a spore and the second stage is the leafy stage, which develops from the secondary protonema as a lateral bud. Female gametophytes are not free-living in gymnosperms. Marchantia is a liverwort and consists of Antheridiophores and archegoniophores. In pteridophytes, the development of the zygotes in female gametophytes is a precursor to the seed habit and is thus considered an important step in evolution.

Ques. Differentiate between Pinus and Cycas?

Ans. The differences are as follows:

Read More: Difference Between Fungi and Lichens

Very Long Answer Questions (5 Marks Questions)

Ques. List five characteristic features of Bryophytes.

Ans. The characteristic features of Bryophytes are as follows:

• They are thallus-like, prostate or erect.
• They have a root-like structure called rhizoids.
• They possess root-like, stem and leaf-like structures.
• The main plant body is a haploid.
• They have dominant gametophyte

Ques. What is the economic importance of bryophytes?

Ans. The economic importance of bryophytes is as follows:

1. Mosses provide food for herbivores, birds and other animals.
2. Sphagnum provides peat that is used as a fuel.
3. They help in the ecological succession of plants.
4. Marchantia has been used for the treatment of pulmonary tuberculosis etc.

Read More: Difference between Bryophytes and Pteridophytes

Ques. Describe the structure of the embryo sac.

Ans. The embryo sac is the female gametophyte of a seed plant. The pistil consists of an ovary which consists of multiple ovules. Within ovules, female gametophytes or embryo sac is present. Each embryo sac comprises a three-celled egg apparatus – one egg cell and two synergids, three antipodal cells and two polar nuclei.

Ques. Describe the process of double fertilization in angiosperms.

Ans. The pollen grains fall on stigma by pollination. As soon as they fall on the stigma, the stigma releases sticky substances which result in the germination of pollen tubes. It grows through the stigma and style and reaches the ovule. The pollen tube enters the embryo sac where two male gametes are discharged. Out of two, one male gamete fuse with the egg cell to form a zygote (syngamy). The other male gamete fuses with the diploid secondary nucleus to produce the triploid primary endosperm nucleus (PEN). As it involves two fusions, it is known as double fertilisation. The zygote then develops into an embryo and the PEN develops into endosperm which provides nourishment to the developing embryo. After fertilization, the synergids and antipodals get degenerate.

Ques. Write advantages of fern?

Ans. The advantages of ferns are as follows-

• Medicinal use- They are used as astringents to stop bleeding during the birth of a child.
• Ornamental- They are used for decoration.
• Furniture- Their wood is resistant to termites and thus is good for making high-quality furniture.

Read More: Apogamy & Apospory

Ques. Differentiate between gymnosperm and Angiosperm.

Ans. The differences between gymnosperms and angiosperms are as follows

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