In 'S' phase of the cell cycle:                                                                                                                      
1. amount of DNA doubles in each cell.
2. amount of DNA remains same in each cell.   
3. chromosome number is increased  
4. amount of DNA is reduced  to half in each cell.

Spindle fibres attach on to:                                                                                                                                
1. Kinetosome of the chromosome
2. Telomere of the chromosome
3. Kinetochore of the chromosome
4. Centromere of the chromosome

A cell at telophase stage is observed by a student in a plant brought from the field. He tells his teacher that this 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

During cell growth, DNA synthesis takes place in

A bacterium divides every 35 minutes. If a culture containing 10⁵ cells per mL is grown for 175 minutes, what will be the cell concentration per mL after 175 minutes ? 

1. 175 × 10⁵ cells
2. 85 × 10⁵ cells
3. 35 × 10⁵ cells
4. 32 × 10⁵ cells

Best material for the study of mitosis in laboratory is
1. anther
2. root tip
3. leaf tip
4. ovary

In the somatic cell cycle:

If you are provided with root-tips of onion in your class and are asked to count the chromosomes, which of the following stages can you most conveniently look into?

At what stage of the cell cycle are histone proteins synthesized in a eukaryotic cell?
1. During telophase
2. During S-phase
3. During G₂ stage of prophase
4. During entire prophase

Four healthy people in their 20s got involved in injuries resulting in damage and death of a few cells. Which of the following cells are least likely to be replaced by new cells ?
1. Osteocytes
2. Liver cells
3. Neurons
4. Malpighian layer of the skin