Optionals IAS Mains Botany: Questions 60 - 66 of 511

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Question 60

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Appeared in Year: 2014 (IFS)

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Essay▾

Stages depicting the formation of vegetative and generative cells during male gametophyte development in angiosperms (Paper - 1, Section - B)

Explanation

Formation of Vegetative and Generative Cells During Male Gametophyte Development in Angiosperms

  • Development of male gametophyte starts in pollen grains.
  • Microspore undergoes mitotic divisions and forms two unequal cells; vegetative cell and generative cell.
  • The larger cell is called vegetative cell and the smaller cell is called generative cell or ger…

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Question 61

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Appeared in Year: 2014 (IFS)

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Comment on Plumbago type of embryo sac development. (Paper - 1, Section - B)

Explanation

Tetrasporic Embryosac

  • It is formed by all four megaspore nuclei because meiosis is not accompanied by Cytokinesis, so that four nuclei of megaspores are formed.
  • All four nuclei are collectively known as “Coenomegaspore” .
  • Generally all the four Nuclei of megaspores take part in the formation of the seven celled and eight nucleated embryosac.
  • Beside thi…

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Question 62

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Appeared in Year: 2014 (IFS)

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Why are gymnosperms called naked-seeded plants? (Paper - 1, Section - B)

Explanation

Gymnosperms as Naked-Seeded Plants

  • Gymnosperms do not produce fruit, their seeds are naked or exposed to the elements without a layer of fruit to protect them.
  • Gymnosperms are different from angiosperms on the basis of the naked-seed habit and enclosure of seeds within a fruit in the latter.
  • Gymnosperm pollen lands directly on the ovule, where in angi…

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Question 63

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Appeared in Year: 2014 (IFS)

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Draw scientifically accurate diagrams of the following and label the parts: L. S. of capsule of Funaria (Paper - 1, Section - B)

Explanation

Image Showing L. S. Of Capsule of Funaria

Funaria Capsule

  • A mature sporogonium or sporophyte of Funaria is borne at the end of the female branch.
  • It differentiated into foot, seta and capsule.
  • The capsule is highly organized structure.
  • The capsule is pear shaped and spore producing structure.
  • Capsule consists of apophysis, annulus, columella, outer and i…

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Question 64

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Appeared in Year: 2014 (IFS)

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Draw scientifically accurate diagrams of the following and label the parts: Floral formula and floral diagram of Ranunculaceae and Rosaceae (Paper - 1, Section - B)

Explanation

Ranunculaceae

Image Showing Floral Formula & Floral Diagram of Ranunculaceae

Rosaceae

Image Showing Floral Formula and Diagram of Rosaceae Family

Question 65

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Appeared in Year: 2014 (IFS)

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Draw scientifically accurate diagrams of the following and label the parts: Anatomy of Pinus needle (Paper - 1, Section - B)

Explanation

Image Showing Pine Needle Anatomy

Anatomy of Pinus Needle or Pinus Leaf

Epidermis

  • Single layered, thick walled and cutinized.
  • Stomata are distributed the entire surface of the leaf, so the leaf is described as amphistomatic.
  • The guard cells of the stomata are sunken below the level of epidermis.
  • Below the stomata there is an air-cavity.

Hypodermis

  • Hypoderm…

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Question 66

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Appeared in Year: 2014 (IFS)

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Differentiate between Megasporogenesis and megagametogenesis. (Paper - 1, Section - B)

Explanation

Megasporogenesis

  • The formation and development of megaspores is called Megasporogenesis.
  • The formation of megaspores occurs inside the ovules of seed plants. A diploid cell in the ovule is called megaspore mother cell which is undergoes to the meiosis and form four haploid megaspores.
  • In most plants, out of four only one megaspore develops into a mega…

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