DNA replication in bacteria occurs
(1) during S-phase
(2) within nucleolus
(3) prior to fission
(4) just before transcription
During cell growth, DNA synthesis takes place in
(1) S-phase
(2) -phase
(3) -phase
(4) M-phase
A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that his cell is not like other cells at telophase stage. There is no formation of cell plate and thus the cell is containing more number of chromosomes as compared to other dividing cells. This would result in
(1) polyploidy
(2) somaclonal variation
(3) polyteny
(4) aneuploidy
Spindle fibres attach on to
1. Kinetochore of the chromosome
2. centromere of the chromosome
3. Kinetosome of the chromosome
4. telomere of the chormosome
In meiosis crossing over is initiated at
1. leptotene
2. Zygotene
3. diplotene
4. pachytene
During cell growth, DNA synthesis takes place in:
1. S phase
2. G1 phase
3. G2 phase
4. M phase
1. | Pachytene | 2. | Diplotene |
3. | Diakinesis | 4. | Zygotene |
Which of the following options gives the correct sequence of events during mitosis?
1. | Condensation, nuclear membrane disassembly, arrangement at the equator, centromere division, segregation, telophase |
2. | Condensation, crossing over, nuclear membrane disassembly, segregation, telophase |
3. | Condensation, centromere division, segregation, arrangement at the equator, telophase |
4. | Condensation, nuclear membrane disassembly, crossing over, segregation, telophase |
1. G1/S
2. G2 /M
3. M
4. Both G2/M and M
Column I | Column II | ||
(a) | pachytene | (1) | pairing of homologous chromosomes |
(b) | metaphase I | (2) | terminalisation of chiasmata |
(c) | diakinesis | (3) | crossing-over takes place |
(d) | zygotene | (4) | chromosomes align at equatorial plate |