ICMR JRF Life Science Exam July 2017
Model Question Paper (6)
(Practice Questions with Answer Key)
1. The exact function of leg hemoglobin in the root nodule induced by Rhizobium in legume plants is:
a. Transport of oxygen
b. Transport of Nitrogenase to the nodule
c. Transport of nitrates from the nodule
d. Protection of Nitrogenase enzyme
2. The genome of CaMV (Cauliflower Mosaic Virus) is:
a. Single stranded RNA
b. Single stranded DNA
c. Double stranded DNA
d. Double stranded RNA
3. The Wallace line separates:
a. Australia from Asia
b. Japan from Philippines
c. India from Madagascar
d. Europe from Africa
4. Parthenium is a ______.
a. K selected species
b. r selected species
5. During the germination of seeds, glucose are synthesized from lipids through the pathway:
a. De novo syntheses
b. Malate aspartate shuttle
c. Glyoxylate cycle
d. Hexose monophosphate shunt
6. The main role of opines in the crown gall disease:
a. Transfer of Ti plasmid to the plant nucleus
b. Facilitate the penetration of Agrobacterium
c. Induce the expression of vir gene
d. Acts as the source of Nitrogen and energy for Agrobacterium
7. An important plant hormone involved in the germination process of seeds:
d. Abscisic acid
8. What will be the ploidy of plants generated by anther culture of Datura?
d. Haploid and Diploid
e. Haploid, Diploid and Polyploid
9. The term ‘tonoplast’ denote:
a. The membrane of vacuole
b. The membrane of endosome
c. The membrane of mitochondria
d. The inner membrane of mitochondria
10. The theory of Island biogeography was developed by:
a. Wilson and MacArthur
d. de Vries
11. The progeny of Breeder’s seed is called:
a. Commercial seed
b. Foundation seed
c. Registered seed
d. Certified seed
12. Carbohydrates in plants are translocated in the form of:
13. The synthesis of cell wall polysaccharides occurs in:
d. Plasma Membrane
14. A live plant cell without nucleus:
a. Sieve tube
b. Companion Cell
c. Guard cell
d. Both (a) and (b)
e. Both (b) and (c)
15. The source of oxygen in photosynthesis is:
Answer Key and Explanations
1. Ans. (d). Protection of Nitrogenase enzyme
Leghemoglobin is a red coloured hemoprotein found in the root nodules of leguminous plants. This protein is produced only when the Rhizobium infects and induces gall formation in leguminous plants. Similar to hemoglobin, the leghemoglobin can binds to oxygen with high affinity. The affinity of leghemoglobin towards oxygen is about 10 times more than that of hemoglobin. The nitrogen fixing process in the symbiotic nitrogen fixation process between leguminous plants and Rhizobium is facilitated by the enzyme nitrogenase. The nitrogenase enzyme is extremely sensitive to high oxygen concentration. The leghemoglobin buffer the oxygen concentration in the cytoplasm of the infected cells to ensure the optimum activity of nitrogenase enzyme.
2. Ans. (c). Double stranded DNA
Cauliflower Mosaic Virus or CaM is a Pararetrovirus that infects plants. Pararetrovirus replicate through the reverse transcriptase enzyme just like a retrovirus but the viral particle contain the genetic material DNA instead of RNA. The promoter of 35S RNA in CaM virus is a very strong constitutive promoter. This promoter, named as CaM 35S promoter, is extensively used in plant transformation experiments for the production of transgenic plants.
3. Ans. (a). Australia from Asia
Wallace line is a faunal boundary that separates the eco-zones of Asia and Australia. This line was drawn by Alfred Russel Wallace in 1859 to demark the fauna of Asia and Wallacia. Wallacea is an imaginary transitional zone between Asia and Australia.
4. Ans. (b). r-Selected species
Parthenium is a noxious weed and it is an r-selected species. An r-selected species is characterized by relatively small body size, high reproductive capacity and short life span with a relatively short juvenile period.
5. Ans. (c). Glyoxylate cycle
Glyoxylate cycle is an alternate pathway of TCA cycle where the Acetyl Co-A is converted to succinate for the synthesis of carbohydrates. The glyoxylate cycle is found only in plants, fungi and bacteria. Glyoxylate cycle enable them to utilize simple carbon sources such as lipids.
6. Ans. (d). Acts as the source of Nitrogen and Energy for Agrobacterium
Opine synthesis in crown gall is facilitated by the enzyme produce from the T-DNA of the Ti plasmid.
7. Ans. (b). Gibberellins
8. Ans. (d). Haploid and Diploid
Anther wall is diploid and they will give diploid individuals whereas the young pollen grains are haploid and thus they will give rise to haploid individuals.
9. Ans. (a). The membrane of vacuole
The membrane of plant vacuole is called tonoplast.
10. Ans. (a). Wilson and MacArthur
Theory of Island Biogeography explains the species richness of an oceanic island.
11. Ans. (b). Foundation seed
Breeder’s seed: The progeny of a successful plant hybridization experiment, done by an authorized plant breeder in an authorized agricultural institution. A golden yellow colour certificate is used to denote the breeder’s seed. Breeder’s seed forms the source of Foundation seed.
Foundation seed: The progeny of Breeder’s seed produced by a recognized seed producing agency. It forms the source of certified seed. A white colour certificate is used to denote the foundation seed.
Certified seed: The progeny of foundation seed, produced by a registered seed grower as per minimum seed certification standards. Certified seeds are used by the farmers. A blue colour certificate is used to denote the certified seed.
12. Ans. (d). Sucrose
13. Ans. (c). Cytoplasm
14. Ans. (a). Sieve Tube
Sieve tube is the component of phloem. The carbohydrate is translocated through sieve tubes of phloem in plants.
15. Ans. (c). H2O
Hydrolysis of water during photosynthesis release Oxygen, protons and elections as per the equation given below: