DNA replication in bacteria occurs

(1) during S-phase

(2) within nucleolus

(3) prior to fission 

(4) just before transcription 

Which of the following options gives the correct sequence of events during mitosis?

Anaphase Promoting Complex (APC) is protein degradation machinery necessary for proper mitosis of animal cells. If APC is defective in a human cell, which of the following is expected to occur?

1. Chromosomes will be fragmented

2. Chromosomes will not segregate

3. Recombination of chromosome arms will occur

4. Chromosomes will not condense

During cell growth, DNA synthesis takes place in

(1) S-phase                       

(2) ${\mathrm{G}}_1$-phase

(3) ${\mathrm{G}}_2$-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