8
MCQ (Single Correct Answer)
Which of the events listed below is not observed during mitosis?
A
Chromatin condensation
B
Movement of centrioles to opposite poles
C
Appearance of chromosomes with two chromosome joined together at the centromere
D
Crossing over
9
MCQ (Single Correct Answer)
Identify the wrong statement about meiosis
A
Pairing of homologous chromosomes
B
Four haploid cells are formed
C
At the end of meiosis the number of chromosomes are reduced to half
D
Two cycle of DNA replication occurs
10
MCQ (Single Correct Answer)
Select the correct statement about $G_1$ phase
A
cell is metabolically inactive
B
DNA in the cell does not replicate
C
it is not a phase of synthesis of macromolecules
D
cell stops growing
11
Between a prokaryote and a eukaryote, which cell has a shorter cell division time?
Explanation
Prokaryotic cell has shorter cell cycle than the eukaryotic cell.
12
Which of the phases of cell cycle is of longest duration?
Explanation
Interphase is of the longest duration. It has following events and is divided in the following phases
(a) $G_1$ phase (Gap 1) Corresponds to the interval between mitosis and initiation of DNA replication. Cell is metabolically active and continuously grows but does not replicate its DNA.
(b) S-phase (Synthesis phase) Marks the period during which DNA synthesis or replication takes place.
(i) Amount of DNA per cell doubles.
(ii) No increase in chromosome number.
(c) $\mathrm{G}_2$ Phase (Gap 2) Proteins are synthesised for the preparation of cell division, while cell growth continues.