Optionals IAS Mains Botany: Questions 409 - 416 of 511

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Question 409

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Appeared in Year: 2018 (IFS)

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Essay▾

How do you justify Asteraceae as a phylogenetically advanced family in dicotyledons?

Explanation

Asteraceae

  • Family is named after its flower shape that is star shape.
  • It contains 950 genera and 22,000 species.
  • It is 10 % of total angiosperm population.
Advanced Characters

Advanced Characters

  • The family Asteraceae also known as Compositae.
  • It is regarded as the most advanced and highly evolved.
  • They are considered to occupy the highest position in the …

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Question 410

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Appeared in Year: 2018 (IFS)

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Write a brief note on Hotspots in India Characteristics and conservations

Explanation

Biodiversity Hotspots

  • Biodiversity hotspots are regions with high species richness and a high degree of endemism.
  • India due to its unique geographical position, distinct physiographic and climate zones, and gradients has a very rich and diverse flora fauna with high [percentage of endemism.
  • Hotspots covers less than 2 percent of the world land but con…

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Question 411

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Appeared in Year: 2018 (IFS)

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What is haploid cell culture? How is this technique useful in agriculture?

Explanation

Haploid Cells

  • Haploid cells may be obtained either by in vitro Androgenesis or by in vitro gynogenesis.
  • In-vitro Androgenesis is the culture of anther, pollen or microspores.
  • In-vitro gynogenesis is the culture of unfertilized egg cells, cells of embryo sac, ovary etc.

Anther Culture

  • It is a technique by which the deploying anther is exercised specially…

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Question 412

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Appeared in Year: 2018 (IFS)

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Describe different methods of selection and hybridization in plant breeding. Give a note on heterosis breeding.

Explanation

Plant Breeding

Methods of Selection

  • Selection is a process to choose male and female mate for desirable offspring՚s.
    • Single trait
    • Multiple trait

Tandem Selection

  • In this type of selection, one trait is in focus at the time until a satisfactory level of performance is achieved.
  • Selection cause change in result to correlated traits.

Independent Culling Level…

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Question 413

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Appeared in Year: 2018 (IFS)

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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 (IFS)

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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 (IFS)

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

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Question 416

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Appeared in Year: 2018 (IFS)

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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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