Q. No.In S–phase, DNA is replicated in a medium containing radioactive thymidine. Radioactivity will be observed in:
| 1. | Euchromatin | 2. | Heterochromatin |
| 3. | Both | 4. | Nucleolus |
Amount of cellular DNA increases during:
| 1. | Cytokinesis | 2. | Fertilisation |
| 3. | Mutation | 4. | Respiration |
Spindle fiber unites with which structure of chromosomes:
1. Chromocenter
2. Chromomere
3. Kinetochore
4. Centriole
At which stage of the cell cycle does DNA replication occur:
1. G1 - phase
2. S - phase
3. G2 - phase
4. M - phase
The best material for the study of mitosis in the laboratory:
| 1. | Anther | 2. | Root tip |
| 3. | Leaf tip | 4. | Ovary |
If a diploid cell is treated with colchicine then it becomes:
1. Triploid
2. Tetraploid
3. Diploid
4. Monoploid
The cells of the quiescent centre are characterised by:
| 1. | Having dense cytoplasm and prominent nuclei |
| 2. | Having light cytoplasm and small nuclei |
| 3. | Dividing regularly to add to the corpus |
| 4. | Dividing regularly to add to tunica |
Which one of the following precedes the reformation of the nuclear envelope during the M phase of the cell cycle:
| 1. | Decondensation from chromosomes and reassembly of the nuclear lamina |
| 2. | Formation of the contractile ring and formation of the phragmoplast |
| 3. | Formation of the contractile ring and transcription from chromosomes |
| 4. | Transcription from chromosomes and reassembly of the nuclear lamina |
Crossing over that results in genetic recombination in higher organisms occurs between:
| 1. | Non-sister chromatids of a bivalent |
| 2. | Two daughter nuclei |
| 3. | Two different bivalents |
| 4. | Sister chromatids of a bivalent |
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