Tuesday, October 27, 2020

2020 March | HSE +2 Exam | Botany - Answers

PART A: BOTANY

ANSWERS 

1. (a) Producers

2. (c) ampR

3. (d) Jaya

4. It is a morphologically and genetically similar individuals/ cells.

5. Natality.

6. Climatic changes, El Nino Effect, Melting of polar ice etc.

7. Hydrarch succession: It is the succession in water body that leads to change from hydric to mesic condition.

Xerarch succession: It is the succession in dry areas that leads to change from xeric to mesic condition.

8. 1. Sanitary landfills, 
    2. Recycle, 
    3. Incineration etc.

9.  

A

B

(a)    Rhizome

(iii) Ginger

(b)    Bulbil

(i) Agave

(c)    Offset

(ii) Water hyacinth

(d)    Leaf buds

(v) Bryophyllum


10. A= Exponential growth / J- shaped growth curve.
      B= Logistic growth / S- shaped growth curve.

11. When an insect ingests the toxin, it becomes active due to alkaline pH of the gut which solubilise the crystals. Toxin binds to surface of epithelial cells creating pores. It causes death of the insect.

12. (a) Pyramid of number:


(b) Pyramid of biomass:


13. True fruit is developed from ovary.
      False fruit is developed from any parts other than ovary (e.g. from thalamus).

14. Biofortification is the breeding crops with high levels of vitamins, minerals, proteins etc. to improve public health.

    Objectives:
  • To improve Protein content and quality.
  • To improve Oil content and quality.
  • To improve Vitamin content.
15. Treating the cells with specific concentration of a divalent cation such as calcium.
      Incubating the cells with recombinant DNA on ice. 
      Place them briefly at 420C (heat shock). 
      Again, place them back on ice.

16. ⦁ Polymerase Chain Reaction (PCR).
      ⦁ Enzyme Linked Immuno-Sorbent Assay (ELISA). 
      ⦁ Autoradiography etc. 

17. 
  1. Autogamy: Transfer of pollen grains from the anther to the stigma of the same flower.
  2. Geitonogamy: Transfer of pollen grains from the anther to the stigma of another flower of the same plant.
  3. Xenogamy: Transfer of pollen grains from the anther to the stigma of a different plant.
18. 
  1. Good ozone is the ozone found in the stratosphere which prevents harmful UV rays.
  2. When CFCs reach stratosphere, UV rays act on them releasing Cl atoms. In presence of Cl (catalyst), ozone degrades to O2. This causes ozone depletion
19. (a) A= Polymerase Chain Reaction (PCR)
           B= Gel electrophoresis. 
      (b) PCR is used for the amplification of gene of interest.
            Gel electrophoresis is used to separate DNA fragments of different sizes.

20.

Competition

Parasitism

Mutualism

·   Abingdon tortoise and goat

·   Belanus and Chathamalus bemacles

·  Cuscuta and host tree

·  Lice on humans

·      Fig tree and wasp

·      Algae and fungi in Lichens


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