Crossing over
1. Occurs in dyad stage of meiosis.
2. Causes recombination between genes of homologous chromosomes.
3. Occurs after chiasmata formation in leptotene.
4. Occurs in diplotene, the longest phase of meiosis.
1. | Pachytene | 2. | Diplotene |
3. | Diakinesis | 4. | Zygotene |
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 |
A somatic cell that has just completed the S-phase of its cell cycle, as compared to a gamete of the same species has:
1. | twice the number of chromosomes and twice the amount of DNA |
2. | the same number of chromosomes but twice the amount of DNA |
3. | twice the number of chromosomes and four times the amount of DNA |
4. | four times the number of chromosomes and twice the amount of DNA |
The microtubules from the opposite poles of the spindle attach to the pair of homologous chromosomes in
1. Metaphase - I
2. Prophase - I
3. Metaphase
4. Metaphase - II
Given below is the representation of a certain event at a particular stage of a type of cell division. Which is this stage?
1. Prophase-I during meiosis
2. Prophase-II during meiosis
3. Prophase of mitosis
4. Both prophase and metaphase of mitosis
Which stages of cell division do the following figures A and B represent respectively?
1. | Metaphase- Telophase | 2. | Telophase- Metaphase |
3. | Late anaphase- Prophase | 4. | Prophase- Anaphase |
The material, which arrests cell division, is obtained from:
1. Crocus
2. Colchicum
3. Dalbergia
4. Chrysanthemum
Phage genome site on bacterial chromosome resulted in which structure?
1. Nucleic acid
2. heterocyst
3. Prophase
4. None of these