Optionals IAS Mains Botany: Questions 338 - 347 of 422

Access detailed explanations (illustrated with images and videos) to 422 questions. Access all new questions- tracking exam pattern and syllabus. View the complete topic-wise distribution of questions. Unlimited Access, Unlimited Time, on Unlimited Devices!

View Sample Explanation or View Features.

Rs. 900.00 -OR-

How to register? Already Subscribed?

Question 338

Edit

Appeared in Year: 2017

Describe in Detail

Essay▾

discuss Vavilov’s centres of diversity.

Explanation

Vavilov’s Centres of Diversity

  • These centres theory is given by Nikolai Ivanovich Vavilov’s, on the origin of cultivated plants.
  • His deductions were based on a variety of evidences, obtained from morphology, anatomy, cytology, genetics, plant geography and distribution.
  • The data was collected by the different part of the world about cultivated plants

… (399 more words) …

Question 339

Edit

Appeared in Year: 2017

Describe in Detail

Essay▾

Explain the bio-chemical and molecular basis of mutations.

Explanation

Molecular Basis of Mutation

There are four molecular basis of mutation.

Base Substitution

  • One base in the DNA molecule is replaced by another base.
  • Two type of base substitution
  • Transition- in transition purine replaced by purine whereas pyramidines replaced by pyramidines.
  • Transersion – in Transersion purine replaced by pyramidines and pyramidines repla

… (239 more words) …

Question 340

Edit

Appeared in Year: 2017

Describe in Detail

Essay▾

Explain the developmental stages in pinus male gametophyte.

Explanation

Developmental Stages in Pinus Male Gametophyte

  • The microspore divides asymmetrically into a small lenticular cell and a larger cell.
  • First prothallial cell does not divide further.
  • The apical cell is larger cell and it divides asymmetrically it form lenticular second prothallial cell and large antheridia cell.
  • The second prothallial cell does not divid

… (233 more words) …

Question 341

Edit

Appeared in Year: 2017

Describe in Detail

Essay▾

Intellectual property rights.

Explanation

Intellectual Property Rights

  • Intellectual property rights have been created to conserve and protect someone’s creation or discovery. so that he/she have right to enjoy their creations and discoveries.
  • They are formed to ensure protection of creations and discoveries against their unfair trade or other illegal practices.
  • The protection is granted by th

… (182 more words) …

Question 342

Edit

Appeared in Year: 2017

Describe in Detail

Essay▾

Describe sporophyte development in Bryophytes with suitable illustrations.

Explanation

Saprophyte Development in Bryophytes

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

… (747 more words) …

Question 343

Edit

Appeared in Year: 2017

Describe in Detail

Essay▾

Define Telome. Discuss Zimmermann’s Telome concept citing examples from major pteridophyte groups.

Explanation

Telome Theory

  • The present day plants with leaves and branches have evolved from the axial sporophyte of the most primitive land plants.
  • The earlier vascular plants had a simple dichotomously branched axis with leaves and roots. Some of them bore sporangia on their terminal branches while others are sterile.
  • It is believed that from these simple vascul

… (330 more words) …

Question 344

Edit

Appeared in Year: 2017

Describe in Detail

Essay▾

What is meant by Anomalous Secondary Growth? Give a descriptive account on comparison of normal and anomalous secondary growth in dicot with examples illustrations, wherever necessary.

Explanation

Anomalous Secondary Growth

  • Anomalous secondary growth is the result of derivation in the cambial activity from the single cylindrical cambium that is normal type in most of the dicotyledons.
  • Anomalous growth is not only seen in dicotyledons but also seen in monocotyledons.
  • In anomalous secondary growth the position of cambium, number of cambium and fu

… (443 more words) …

Question 345

Edit

Appeared in Year: 2017

Describe in Detail

Essay▾

Molecular basis of sex determination.

Explanation

Sex Determination

  • It is a biological system that determine the development of the sexual characters of an organism.
  • Most of the mechanisms of the determination of the sex are controlled in molecular level.
  • They classified into these categories
    • Sex chromosome mechanism or Heterogamesis
    • Genic balance mechanism
    • Male haploidy or haplodiploidy mechanism
    • Single

… (322 more words) …

Question 346

Edit

Appeared in Year: 2017

Describe in Detail

Essay▾

Chi square test.

Explanation

Chi Square Test

  • Chi- square is most popular method to determine the goodness of fit.
  • To solve any problem take four steps
    • State the hypothesis
    • Formulate the analysis plan
    • Analyze sample data
    • Result interpretation

State the Hypothesis

  • Every hypothesis test requires a Null hypothesis (H0) and the alternative hypothesis.
  • Both hypothesis state such a way that t

… (269 more words) …

Question 347

Edit

Appeared in Year: 2017

Describe in Detail

Essay▾

With suitable example, explain the tripartite sex determination.

Explanation

Sex Determination

  • It is a biological system that determines the development of the sexual characters of an organism.
  • In some angiosperm the tripartite sex determination is seen.

Tripartite Sex Determination

Involvement of three sex chromosome to determine the development of sexual characters of an organism. For example- XXX or XXY, etc.

For Example

  • In Ac

… (80 more words) …