For its action, nitrogenase requires:
1. Light
2. Mn2+
3. Super oxygen radicals
4. High input of energy
1. Light
2. Mn2+
3. Super oxygen radicals
4. High input of energy
Tobacco plants resistant to a nematode have been developed by the introduction of DNA that produced (in the host cells):
1. A particular hormone
2. An antifeedant
3. A toxic protein
4. Both sense and anti-sense RNA
Where do certain symbiotic microorganisms typically occur in the human body?
1. Oral lining and tongue surface
2. Vermiform appendix and rectum
3. Duodenum
4. Caecum
Identify the meiotic stage in which the homologous chromosomes separate while the sister chromatids remain associated at their centromeres.
1. Metaphase-II
2. Anaphase-I
3. Anaphase-II
4. Metaphase-I
Which one of the following cellular parts is correctly described?
| 1. | Centrioles - sites for active RNA synthesis |
| 2. | Ribosomes - those on chloroplasts are larger (80s) while those in the cytoplasm are smaller (70s) |
| 3. | Lysosomes - optimally active at a pH of about 8.5 |
| 4. | Thylakoids - flattened membranous sacs forming the grana of chloroplasts |
The supportive skeletal structures in the human external ears and the nose tip are examples of:
1. Areolar tissue
2. Bone
3. Cartilage
4. Ligament
Read the following five statements (I - V) and answer as asked next to them.
| I. | In Equisetum, the female gametophyte is retained on the parent sporophyte |
| II. | In Ginkgo, male gametophyte is not independent |
| III. | The sporophyte in Riccia is more developed than that in Polytrichum |
| IV. | Sexual reproduction in Volvox is isogamous |
| V. | The spores of slime molds lack cell walls |
How many of the above statements are correct?
| 1. Three | 2. Four |
| 3. One | 4. Two |
Identify the molecules (a) and (b) shown below and select the right option giving their source and use.
| (I) |  |
| (II) |  |
|
Molecule |
Source |
Use |
|
|
1. |
(II) Heroin |
Cannabis sativa |
Depressant and slows down body functions |
|
2. |
(II) Cannabinoid |
Atropa belladonna |
Produces hallucination |
|
3. |
(I) Morphine |
Papaver somniferum |
Sedative and painkiller |
|
4. |
(I) Cocaine |
Erythroxylum coca |
Accelerates the transport of dopamine |
The figure below shows three steps (A, B, C) of Polymerase Chain Reaction (PCR). Select the option giving correct identification together with what it represents.
| 1. | A - Denaturation at a temperature of about 50ºC |
| 2. | C - Extension in the presence of heat-stable DNA polymerase |
| 3. | A - Annealing with two sets of primers |
| 4. | B - Denaturation at a temperature of about 98ºC separating the two DNA strands |
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