Optionals IAS Mains Botany: Questions 413 - 420 of 422

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Question 413

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Appeared in Year: 2018

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Essay▾

Write a brief note on role of Rubisco in carbon metabolism.

Explanation

Rubisco

  • Rubisco also known as Ribulose-1,5-bisphosphate carboxylase/oxygenase enzyme.
  • It the enzyme involve in first step of carbon fixation.

In Light Reaction

  • Rubisco activity provides the acceptor molecules (PGA) necessary to hydrolyse ATP and oxidize NADPH to continue electron transport.
  • It catalyses the entry of carbon dioxide into photosynthetic me

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Question 414

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Appeared in Year: 2018

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Explain the progressive sterilization of potentially sporogenous tissue found in Bryophyte. Add a note on the role of elaters.

Explanation

Evolution

  • Evolution of sporophyte by progressive sterilization of sporophyte is also known as theory of progressive evolution.
  • The sporophytes of complex forms have evolved due to progressive sterilization of the potential fertile tissue of the simpler forms.
  • In primitive form the sporophyte is simple and most of the tissue of the sporophyte is fertil

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Question 415

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Appeared in Year: 2018

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Illustrate the structure of ATP synthase and discuss the mechanism of ATP synthesis in higher plants.

Explanation

Structure of ATP Synthesis in Higher Plants

  • ATP synthase embedded in the thylakoid membrane.
  • Moreover, it functions as a rotor.
  • In the chloroplast, protons in the Stroma decrease in number, while in the lumen there is accumulation of protons.
Structure of ATP synthase

Structure of ATP Synthase

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  • This creates a proton gradient across the thylakoid membrane as well a

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Question 416

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Appeared in Year: 2018

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Discuss the mechanism of nitrogen fixation associated with legumes and elaborate the factors controlling the process.

Explanation

Mechanism of Nitrogen Fixation

  • In Legumes, nitrogen fixation starts with the formation of a nodule.
  • The rhizobia bacteria in the soil enter inside the root and multiply within its cortex cells.
  • The plant supplies all the necessary nutrients and energy for the bacteria.
  • Before 2 - 3 week, small nodules are visible depending upon legume species and germi

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Question 417

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Appeared in Year: 2018

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Comment on why Albugo candida and Phytophthora infestans are not considered as fungi.

Explanation

Albugo and Phytophthora

  • Oomycota group of organisms cause many serious plant diseases.
  • Albugo candida and Phytophora infestans belong to this oomycota.
  • The phycomycetes is an informal group which included Oomycota, slime moulds, and chytrids, zygomycetes and arbuscular mycorrhizae. They are called lower fungi.
  • The fungi which consist higher fungi are a

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Question 418

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Appeared in Year: 2018

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Describe the diversity of photosynthetic pigments found in the major classes of Algae.

Explanation

Algae

Pigments

  • Algae have some colours due to presence of some pigment combination.
  • And there are some specific pigments in each class.

Chlorophyll

  • There are five time of chlorophyll a, b, c, d and e.
  • Chlorophyll a present in all groups of algae.
  • Chlorophyll b is present in only in Chlorophyaceae and Euglenophyceae.
  • Chlorophyll c present in mainly marine a

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Question 419

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Appeared in Year: 2018

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Explain the ecological characteristics of different types of forests found in India. Describe briefly about the dominance of vegetation types of tropical and alpine forests.

Explanation

Tropical and Alpine Forests

  • Indian subcontinent lie between 80 and 370 N, and 680 and 970 E has its own peculiar physiographic, climatic and biotic features.
  • There are two most common types of plant formation in India—Forest and grassland.
Photoghraphical Zones

Photoghraphical Zones

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Forest

Tropical Wet Evergreen Forests

  • These forests are found in Western Ghats

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Question 420

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Appeared in Year: 2018

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Describe the evolutionary significance of various stellar structures found in Pteridophytes. Give one suitable example in each case.

Explanation

Stele

It can be define as the central core of the stem and root of a vascular plant, consisting of the vascular tissue and associated supporting tissue.

Type of Stele in Pteridophytes

  • Protostele
  • Siphonostele
  • Dictyostele
  • Eustele

Protostele

In this type of stele central core of xylem completely surrounded by phloem. This is the most primitive and simplest of

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