The drug colchicines, used to obtain polyploidy cells, acts on the cytoskeletal structures of
the plant cells called
1. | microtubules |
2. | actin filaments |
3. | intermediate filaments |
4. | all of the above. |
Astral rays arise from
1. | centriole | 2. | cytoplasm |
3. | chromatid | 4. | centromere. |
Number of mitotic division required in a cell of root tip for formation of 128 cells is
1. 12
2. 3
3. 7
4. 6
Barr body is found in the cytoplasm during
1. | interphase in cell of female mammal. |
2. | interphase in cell of male mammal. |
3. | prophase in cell of female mammal. |
4. | prophase in cell of male mammal. |
When synapsis is complete all along the chromosome, the cell is said to have entered a stage called
1. | Zygotene | 2. | pachytene |
3. | diplotene | 4. | diakinesis. |
Many cells function properly and divide mitotically even though they do not have
(1) Plasma membrane
(2) Cytoskeleton
(3) Mitochondria
(4) Plastids
Which of the following is not a characteristic of meiosis?
1. | It involves two stages of DNA replication one before meiosis-I and another before meiosis-II |
2. | It involves recombination and crossing over |
3. | Sister chromatids separate during anaphase- II |
4. | Nuclear membrane disappears during prophase. |
Microtubule depolymerizing drug such as colchicine is expected to
1. | inhibit spindle formation during mitosis |
2. | inhibit cytokinesis |
3. | allow mitosis beyond metaphase |
4. | induce formation of multiple contractile |
Which of the following statements is incorrect about G0 phase.
1. | Mitosis occurs after G0 phase. |
2. | Biocatalysts can be used to exit G0 phase. |
3. | Cell volume keeps on increasing during this phase. |
4. | Cell metabolism occurs continuously in G0 phase. |
Beads on string like structures of A are seen in B, which further condense to form chromosomes in C stage of cell division.
A | B | C | |
1. | Chromonema | Chromatin | Metaphase |
2. | Chromatin | Chromatid | Metaphase |
3. | Chromonema | Chromosome | Anaphase |
4. | Chromonema | Chromatid | Anaphase |