KERALA PSC / BIOLOGY / CELL DIVISION / NOTES / OBJECTIVE QUESTIONS / STUDY MATERIALS / GENERAL KNOWLEDGE / KERALA PSC PRELIMINARY

 

KERALA PSC / BIOLOGY / CELL DIVISION / NOTES / OBJECTIVE QUESTIONS / STUDY MATERIALS / GENERAL KNOWLEDGE / KERALA PSC PRELIMINARY

KERALA PSC / BIOLOGY / CELL DIVISION / NOTES / OBJECTIVE QUESTIONS / STUDY MATERIALS / GENERAL KNOWLEDGE / KERALA PSC PRELIMINARY

·      Cell division is the process by which a parent cell divides into two or more daughter cells.

·      Rudolf Virchow was the first to suggest that new cells are formed from the division of the pre-existing cells.

·      Depending on the manner in which the nucleus divides, four different kinds of cell divisions are recognized. These are (1) Direct nuclear division or Amitosis (2) Indirect nuclear division or Mitosis (3) Reduction division or Meiosis and (4) Free nuclear division. Here only two main kinds of cell division are described – mitosis and meiosis

·      Mitosis (Karyokinesis) means the division of nucleus and

·      Melosis (Cytokinesis) means the cytoplasmic division.

·      Mitosis was first observed by strasburger (1870) in plant cells, Boveri and Flemming (1879) in animals. The term mitosis was coined by Flemming (1882)

·      The term meiosis was coined by J.B Farmer (1905) with JF Moore

·      Mitosis occur in body cells, results in formation of two daughter cells with equal number of chromosomes.

·      Meiosis occurs in reproductive cells. It causes a reduction in number of chromosomes in the cell.

KERALA PSC / BIOLOGY / CELL DIVISION / NOTES / OBJECTIVE QUESTIONS / STUDY MATERIALS / GENERAL KNOWLEDGE / KERALA PSC PRELIMINARY