Optionals IAS Mains Botany: Questions 264 - 272 of 511

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Question 264

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Appeared in Year: 2016 (IFS)

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Essay▾

Explain the mode of virus infection in T-even phage and Lambda phage.

Explanation

Mode of Virus Infection in T- Even Phage

  • The T- even phage search and bind to receptors.
  • At specific protein structure found on the surface.
  • Every phage has different receptor.
  • There are some receptor like cell wall protein, flagella, pilli, lipopolysaccharides and teichoic acid to bind.
  • Phage tail structure and tail fibres help the it to bind it with t…

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Question 265

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Appeared in Year: 2016 (IFS)

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Essay▾

Distinguish between the Medullary and Cortical vascular bundles.

Explanation

Medullary Vascular Bundle

  • Medullary vascular bundle is situated in the peripheral part of the pith of the stem and in some cases extended to the leaf trace.
  • They are generally small in size.
  • Medullary bundles do not supply to the lateral organs.
  • They traverse throughout the length of the stem without any branching.
  • Large number of medullary bundle is pr…

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Question 266

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Appeared in Year: 2016 (IFS)

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Essay▾

Describe the range of thallus structures in Lichens. Lichens are rare or absent in cities. What conclusion can be drawn from this?

Explanation

Range Thallus Structures in Lichens

Crustose Lichen

  • This type of encrusting lichens with an inconspicuous, thin and flat thallus, firm in texture.
  • The thallus is very closely adhered to the substratum and provides a crust like appearance.
  • They are wholly or partially embedded in the substratum.
  • In the latter case only fruiting bodies are visible above t…

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Question 267

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Appeared in Year: 2016 (IFS)

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Essay▾

Draw well-labelled diagram of the Male flower of Euphorbia.

Explanation

Male Flower of Euphorbia

  • In euphobiace the inflorance is cyanthium type. Cyanthium is surrounded by the four or five connate bracts and between these bracts large and often coloured glands are present.
  • In middle the single female flower is present and in axil of each bract a number of male flower are arranged in scorpioid cyme.
Male Flower of Euphorbia

Question 268

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Appeared in Year: 2016 (IFS)

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Essay▾

Comment on the characteristics of Archaea, Bacteria and Eukarya.

Explanation

Characteristics of Archaea

  • Cell wall- Archaea lack peptidoglycan in its cell wall. it is a distinguishable feature between bacteria and archaea.
  • Fatty acid-Archaea has ether bonds connecting fatty acids to molecules of glycerol.
  • RNA polymerase complexity-Archaea has multiple RNA polymerase that also contains multiple polypeptides (some have 8 polypept…

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Question 269

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Appeared in Year: 2016 (IFS)

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Essay▾

Distinguish between the Cladode and Phyllode.

Explanation

Cladode

  • It is a modification of stem in which a branch of single internode is flatted and becomes leaf like.
  • The leaves reduced to scales in the axil of which develops a group of linear, acute, narrow and circular structure.
  • They are green and photosynthetic.
  • It is a xerophytic adaptation.

    Example of cladode-Asparagus.

Image Show of the Cladode

Phyllode

  • Ph…

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Question 270

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Appeared in Year: 2016 (IFS)

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Essay▾

Differentiate between the Hypanthium and Hypanthodium.

Explanation

Hypanthium

  • In this type of in Florence the peduncle modified in a narrow cup likes structure.
  • At the base of cup the female flower develops whereas at mouth side the male flower develops.
  • All three types of flower are present in this in Florence.

    Example: Peepal and banyan.

Hypanthodium

  • In this type of in Florence the receptacle is flask shaped.
  • Receptacl…

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Question 271

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Appeared in Year: 2016 (IFS)

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Essay▾

Give the name of the causal organism, symptoms and measures to control a plant disease caused by a bacterium.

Explanation

Plant Disease Caused by a Bacterium

Citrus canker

Causal Organism

Xanthomonas Citri

  • It is gram negative, Monotrichous, capsulated bacillus which is strictly aerobic in nature.
  • It shows a yellow, copiously mucoid growth on 2 % sucrose peptone agar but on beef agar colonies are circular and straw yellow to amber yellow.

Symptoms

  • Affects all above ground par…

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Question 272

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Appeared in Year: 2016 (IFS)

Write in Short

Short Answer▾

Draw well-labelled diagrams of the winged pollen of Pinus.