CSIR Life Science Sample Questions (Part 9 of 10)
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- In an animal experiment Electrical stimulation of an area in the brain A increased a function F which was prevented by systemic injection of adrenergic antagonistic, prazosin.Injection of carbachol (cholinergic agonist) into A also increased function F which was, however not prevented by systemic injection of adrenergic antagonistic, prazosin. The results are likely to be due to the stimulation of
- Nonadrenergic and cholinoceptive neurons
- Cholinergic and non-adrenoceptive neurons
- adrenergic terminals in ‘A’
- both neurons and fibres passing through ‘A’
- With respect to the extra embryonic structures formed in the mammals, the possible functional attributes have been designated
- Allantoin stores urinary waste and helps mediate gas exchange. It is derived from splanchnopleure at the caudal end of the primitive streak.
- Amnion is a water sac and protects the embryo and its surrounding amniotic fluid. This epithelium is derived from somatopleure.
- Chorion is essential for gas exchange in amniote embryos. It is generated from the splanchnopleure.
- Yolk sac is the last embryonic membrane to form and is derived from somatopleure.
- Which of the above statements are correct?
- 1 2
- 1 3
- 2 3
- 1 4
- The quantum yield of photosynthetic carbon fixation in a C3 plant and C4 plant is studied as a function of leaf temperature. Following are some statements based on this study.
- At lower temperature the quantum yield of C3 plant is lower than C4 plant.
- In C4 plant quantum yield does not show a temperature dependence.
- Since the photorespiration is low in C4 plants because of CO2 concentrating mechanism, quantum yield is not affected.
- At higher temperature the quantum yield of C3 plant is lower than C4 plant.
- Which one of the following combination of above statements is correct?
- 1 2 4
- 2 3 4
- 1 2 3
- 1 3 4
- The frequencies of two alleles p and q for a gene locus in a population at Hardy-Weinberg equilibrium are 0.3 and 0.7, respectively. After a few generations of inbreeding, the heterozygote frequency was found to be 0.28. The inbreeding coefficient in this case is
- 0.42
- 0.28
- 0.33
- 0.67
- Following are some statements for synthesis of jasmonic acid in plants
- 12-oxo-phytodienoic acid is produced in chloroplast and transported to peroxisome.
- Action of lipoxygenase, allene oxide synthase and allene oxide cyclase takes place in peroxisome.
- 12-oxo-phytodicnoic acid is first reduced and then converted to jasmonic acid by β-oxidation.
- Final production of jasmonic acid takes place in chloroplast. Action of allene oxide synthase and allene oxide cyclase takes place in chloroplast.
- Which one of the following combination of above statements is correct?
- 1 2 3
- 2 4
- 3 4
- 1 3
- Which of the following behavioural changes are expected in a rat when its nucleus accumbens is experimentally ablated?
- Aggressive behaviour increases
- Exploratory behvaiour decreases
- Nest-building activity increases
- Level of parental care drops
- From among the five animals listed below, match the two attributes-amniotic egg and endothermy, with the correct animal (s) :
- fish
- frog
- crocodile
- pigeon and 5 zebra
- Which of the following choice is best suitable?
- Amniotic egg: b, c, d; Endothermy: d, e
- Amniotic egg: c, d, e; Endothermy: d, e
- Amniotic egg: a, b, c, d; Endothermy: c, d, e
- Amniotic egg: b, c, d; Endothermy: c, d, e
- Which of the following is NOT true for a critically endangered species?
- Reduction of population breeding ability due to increased relatedness through the action of incompatibility mechanisms in plants or behavioral difficulties in animals.
- The individuals of the species which have declined to low numbers are still a genetically open system.
- Loss of some alleles from the species causing loss of genetic diversity with consequent inability of respond rapidly to selection.
- Expression of deleterious alleles and increased homozygosity increases mortality of young, and inbreeding depression leads to reduced offspring fitness.