The S-phase of cell cycle is characterized by:
duplication of chromosome
shotening of chromosome
duplication of DNA
duplicatin of centriole
Chiasmata are most appropriately observed in meiosis during :
diakinesis
diplotene
metaphase II
pachytene
Which of the following maintain the constant number of chromosomes generation after generation?
Meiosis
Endomitosis
Mitosis
Amitosis
A.
Meiosis
Meiosis is also known as reduction division. It maintains the constant number of chromosomes generation after generation. It occurs in reproductive cells only and somatic body increases in size through mitotic division.
Match the sub-stage of prophase I of meiosis in Column I and the events in Column II and choose the right option.
Column I | Column II |
A. Leptotene | 1. Terminalization of chiasma |
B. Zygotene | 2. Crossing over and recombination |
C. Pachytene | 3. Synapsis |
D. Diakinesis | 4. Visibility of chromosomes |
A - 1; B - 2; C - 3; D - 4
A - 1; B - 3; C - 2; D - 4
A - 4; B - 3; C - 2; D - 1
A - 4; B - 1; C - 2; D - 3
A - 4; B - 1; C - 2; D - 3
Which one of the following is the significance of mitosis?
Restricted to haploid cells
Cell repair
Increases the genetic variability
Recombination of chromosomes
Recombination of chromosomes
In a typical eukaryotic cell cycle, Gap 1, Synthesis and Gap 2 are the three phases included in the
Prophase
Metaphase
Anaphase
Interphase
Interphase