CBSE Class 11 Biology - Chapter-3 Important Questions

The plant kingdom is very vast with a number of classifications. A plant can be classified into Thallophyta, Bryophyta, Pteridophyta. They are differentiated on the basis of the structure, presence or absence of transport tissues, and the ability to bear seeds. The questions given below will provide a better understanding of the concepts.

Short Answer Type Questions

Q.1. Which group of algae has mannitol as the reserve food material?
A.1. The Phaeophyceae group or the brown algae has mannitol as the reserve food material.

Q.2. Name the plants with

  1. Haplontic life cycle
  2. Diplontic life cycle
  3. Haplo-diplontic life cycle

A.2.

  1. Haplontic life cycle- Volvox
  2. Diplontic life cycle- All seed-bearing plants
  3. Hapiodiplontic life cycle- Bryophytes

Q.3. Roots are used for the purpose of absorption. What is equivalent to roots in less developed lower plants?
A.3. In less developed lower plants root-like structures called rhizoids are present. For eg., in bryophytes and pteridophytes.

Q.4. The male and female sex organs in Bryophytes are called antheridium and archegonium.

Q.5. Match the following:

Column I Column II
Chlamydomonas Moss
Cycas Pteridophyte
Selaginella Algae
Sphagnum Gymnosperm

A.5. Chlamydomonas-Algae Cycas-Gymnosperm Selaginella-Pteridophyte Sphagnum-Moss

Q.6. Cyanobacteria are classified under which kingdom?
A.6. Cyanobacteria are classified under kingdom Monera.

Q.7. What do you mean by anisogamy?
A.7. It is a type of sexual reproduction that involves the fusion of two motile gametes that are dissimilar in size.

Q.8. How many cells an embryo sac is made of?
A.8. The embryo sac is made up of two synergids, one egg cell, three antipodal cells, and one secondary nucleus.

Q.9. What are the three groups of plants that bear archegonia?
A.9. Bryophytes, pteridophytes, and gymnosperms are the three groups of plants that bear archegonia.

Q.10. Why are both gymnosperms and angiosperm in spite of both bearing seeds?
A.10. This happens because in gymnosperms the seeds are not present inside the fruit, while in angiosperms they are enclosed inside the fruit.

Short Answer Type Questions

Q.1. Why are bryophytes considered amphibians of the plant kingdom?
A.1. Bryophytes are considered amphibians of the plant kingdom because they depend on water for the movement of male gametes called antherozoids to reach archegonium for fertilization.

Q.2. Compare the various reproductive parts of pteridophytes and gymnosperms with those of angiosperms.
A.2.

Reproductive parts of pteridophytes and gymnosperms Reproductive parts of angiosperms
Cone Flower
Megasporophyll Anther
Megasporangium Ovule
Microsporangium Stamen
Microsporophyll Pistil/Carpel

Q.3. Does heterospory have some evolutionary significance in the plant kingdom?
A.3. Pteridophytes are intermediate between bryophytes and gymnosperms. Primitive pteridophytes are homosporous while the later pteridophytes are heterosporous. Bryophytes are homosporous and gymnosperms are heterosporous.

Q.4. How far does Selaginella fall short of seed habit?
A.4. Selaginella gives rise to two kinds of spores, megaspores and microspores. These spores germinate and give rise to male and female gametophytes. But, due to lack of integument around the megasporangium, Selaginella falls short of seed habit.

Q.5. Discuss the phylogenetic relationship of Cycas with any other group of plants.
A.5. Cycas is an evergreen plant that looks like a palm. It exhibits a phylogenetic relationship with pteridophyte. The evolutionary characters include:

  • Shedding of seed when the embryo is immature.
  • Slow growth.
  • Monocyclic wood.
  • Little secondary growth.
  • Leaf-like megasporophylls.
  • Circinate ptysix.
  • Persistent leaf bases.
  • Arrangement of microsporangia is well-defined archegonia.

Q.6. Describe the life cycle and nature of a fern prothallus.
A.6. The life cycle of Prothallus: The life cycle of fern exhibits alternation of generations. The fern prothallus is multicellular, free-living, haploid, autotrophic, and thalloid structure. It is developed from the spores produced after reduction division by saprophyte. These spores germinate with a germ tube. It forms a filament of 3-6 cells and rhizoids at the base which develops into a gametophytic plant later.

Q.7. Differentiate between the male and female gametophytes of pteridophytes and gymnosperms.
A.7. Male Gametophytes:

Gymnosperms Pteridophyte
A distinct male gametophyte is always present. A distinct male gametophyte is absent.
Antheridium is not present. Antheridium is present.
Male gametes may or may not be flagellated. Male gametes are flagellated.
Male gametes reach the female gamete through pollen tube. Male gametes reach the female gamete by flowing in water.

Female Gametophytes:

Gymnosperms Pteridophyte
A distinct gametophyte is always present. A distinct gametophyte may or may not be present.
Female gametophyte does not leave the parent plant. It is independent of the parent plant.
Enclosed inside an ovule. Not enclosed inside the ovule.

Q.8. Mycorrhiza and coralloid roots are found in which plants? What do these terms mean?
A.8. Mycorrhiza is the symbiotic association between fungus and roots of vascular plants. The mycorrhizal association is present in conifers such as Pinus, Cedrus, etc. Coralloid roots are present in Cycas. Coralloid roots are present in clusters at the base of the stem and protrude over the ground. It is greenish in colour and dichotomously branched.

Q.9. The heterosporous pteridophytes exhibit certain characterstics which are precursors to the seed habits in gymnosperms. Explain.
A.9. Heterospory is the production of two types of spores; the megaspores and the microspores. The microspores produce male gametophyte which produces male gametes, while the megaspores produce female gametophyte which produces archegonia and provides nourishment to the embryo. Thus, heterospory leads to a reduction of the gametophyte. Thus, heterospory in pteridophytes forms the base of seed habits in gymnosperms.

Long Answer Type Questions

Q.1. How is gametophyte a dominant phase in the life cycle of bryophytes?
A.1. Gametophyte bears the male reproductive organ antheridia and female reproductive organ archegonia, thereby, producing male gametes (antherozoids) and female gametes (egg cell). A gametophyte is a dominant form and the most familiar phase of the life cycle of bryophyte. The antherozoid fuses with the egg to produce a zygote. Zygote forms a multicellular body known as the sporophyte.

Q.2. Describe the life cycle of a plant.
A.2. The life cycle of a plant starts as a seed. The seed germinates and grows like a plant. The plant produces flowers which produce seed in fruit on fertilization. The plant dies and leaves seeds behind which germinate to form a new plant.

Q.3. What do you mean by double fertilization and triple fusion?
A.3. In this process, one male gamete fertilizes the egg and forms a diploid zygote. The other male gametes fuse with the two polar nuclei forming a triploid zygote that develops into the endosperm. This is known as double fertilization. The three haploid nuclei fuse to form endosperm. It is known as triple fusion. For more information on Biology related articles keep visiting BYJU’S website. You can also download BYJU’S app for further reference.

Other related articles

Important Questions for class 12
Important Questions for class 11
Animal Kingdom
Morphology of Flowering Plants


Practise This Question

Macro molecule chitin is: