Cell Cycle and Cell Division Test - 55

Formation of four unidentical daughter cells from a parent cell is called Meiosis. The four daughter cells formed in meiosis are unidentical to the parent cells because of the occurrence of crossing over and independent assortment. During meiosis, chromosomes in a pair are segregate or separate from one another, move into a gamete. Simultaneously, a character or trait separate from its pair and move into a gamete. So, each gamete receive one allele in a pair.

So, the correct option is ‘one’.

• To produce 200 pea seeds 200 pollen grains and 200 eggs are required.
• To produce 200 pollen grains 50 meiotic divisions are required. 
• Whereas, to produce 200 eggs from mother cells 200 meiotic division are required.
• Therefore, a total of 250 meiotic divisions are required to produce 200 seeds of the pea.
  
• The correct answer is $$250/500$$
  

Spindle fibers are the cellular structures which are mainly used during cell division. It forms a protein structure which helps in cell division. They are also known as mitotic spindle. It is made up of 97% tubulin protein and 3% RNA. Alpha and beta tubulin forms the polymeric tubulin. The spindle fibres attach to kinetochore of the chromosomes and divide the cell.

The irreversible permanent increase in size, volume, or weight of the cell is called cell growth. During cell growth, the synthesis of carbohydrates, proteins, fats, lipids, nucleic acids, etc takes place. These changes occur during the interphase and postmitotic phase of the cell cycle.

So, the correct option is option D. 

Correct Option: D

Meiosis is a reductional division. The diploid parent gametes are reduced to the haploid offsprings. It involves the exchange of genes between homologous chromosomes. The homologous chromosomes pairs by crossover are known as synapsis and exchange the chromosomal segment which causes genetic recombination.These variations in the offsprings make organisms more adaptable to the environment and these have a definite role in evolution.

Cell division is a prominent process which involves two major steps karyokinesis and cytokinesis. Karyokinesis involves division of parent nucleus to form the nucleus of the offsprings. Cytokinesis involves the division of the cytoplasm. During mitosis or meiosis, the prophase, metaphase, and anaphase mainly involve karyokinesis. In telophase stage when the chromosomes reach at the two opposite poles, the cell membrane invaginates and forms a furrow like  appearance in the animal cells. The furrow deepens and meets to form a barrier which separates the two daughter cells.