Part B-Dec 2011

CSIR-UGC National Eligibility Test (NET) for Junior Research Fellowship and Lecturer-ship

Part B


1.A specialist species has a

1. wider niche and high efficiency of niche utilization 2. narrower niche and high efficiency of niche utilization 3.wider niche and low efficiency of niche utilization 4.narrower niche and low efficiency of niche utilization

Ans.   2

Expln:- A generalist species is able to thrive in a wide variety of environmental conditions and can make use of a variety of different resources (for example, a heterotroph with a varied diet ). A specialist species can only thrive in a narrow range of environmental conditions or has a limited diet. Some species are highly specialized (the most extreme case being monophagy). Omnivores are usually generalists. Herbivores are often specialists, but those that eat a variety of plants may be considered….

2.Batrachochytrium dendrobatidis, a fungus has been implicated in the decline of populations of

1. fish 2. frogs 3.pelicans 4.bats

Ans.   2

Expln:- Batrachochytrium dendrobatidis (or Bd for short) is a chytrid fungus that causes the disease chytridiomycosis. In the decade after it was first discovered in amphibians in 1998, the disease devastated amphibian populations around the world, in a global ….

3.Which of the following is NOT a physiological characteristic of early successional plants ?

1. High respiration rate 2. Inhibition by far-red light 3.High transpiration rate 4.Low photosynthetic rate

Ans.   4

Expln:- Physiological characteristics of early and late successional plants


ATTRIBUTE                                               EARLY SUCCESSIONAL          LATE SUCCESSIONAL
PLANTS                                                                   PLANTS

Speed dispersed in time                                    Well dispersed                         Poorly dispersed
Seed germination enhanced by light                         Yes                                                No
Fluctuating temperatures                                            Yes                                                No
High NO3                                                                        Yes                                                No
Inhibited by far-red light                                              Yes                                                No
High CO2 concentration                                               Yes                                               No ?
Light saturation intensity                                             High                                             Low
Light compensation point                                            High                                             Low
Efficiency at low light                                                    Low                                              High
Photosynthetic rates                                                     High                                            Low
Respiration rates                                                           High                                            Low
Transpiration rates                                                       High                                             Low
Stomatal & mesophyll resistances                             Low                                             High
Resistance to water transport                                     Low                                             High
Recovery from resource limitation                             Fast                                             Slow
Resource acquisition rates                                           Fast                                            Slow ?

4.Which of the following features is not shown by glyphosate, a broad spectrum herbicide ?

1. Little residual soil activity 2. Ready translocation in phloem 3.Inhibition of a chloroplast enzyme catalyzing the synthesis of aromatic amino acids 4.Inhibition of early steps in the biosynthesis of branched chain amino acids

Ans.   4

Expln:- Glyphosate acts as a competitive inhibitor of the enzyme Enolpyruvylshikimate phosphate synthase (EPSPS). This is a key enzyme in shikimic ….

5.Which of the following processes interferes in sequence-based phylogeny ?

1. Horizontal gene transfer 2. Adaptive mutations 3.DNA repair 4.Reverse transcription

Ans.   1

6.  Which of the following maternal effect gene products regulate production of anterior structures in Drosophila embryo ?

1. Bicoid and Nanos 2. Bicoid and Hunchback 3.Bicoid and Caudal 4.Nanos and caudal

Ans.   2

7.  Which of the following acts as a branch point for the biosynthesis of sesquiterpenes and triterpenes ?

1. Farnesyl pyrophosphate 2. Geranyl pyrophosphate 3.Isopentyl pyrophosphate 4.Hydroxymethylglutaryl – CoA

Ans.   1

8.Which of the floral whorls is affected in agamous (ag) mutants ?

1. Sepals and petals 2. Petals and stamens 3.Stamens and carpels 4.Sepals and carpels

Ans.   3

9. Which of the following set of cell organelles are involved in the biosynthesis of jasmonic acid through octadecanoid signalling pathway ?

1. Chloroplast and peroxisomes           2. Chloroplast and mitochondria

3.Mitochondria and peroxisomes        4.Golgi bodies and mitochondria

Ans.   1

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