#GENETICS MITOSIS The term mitosis was coined by Flemmi | Agriculture Exams Library
#GENETICS
MITOSIS The term mitosis was coined by Flemming in 1882.
Mitosis refers to the spindle using nuclear division which produces two identical daughter nuclei from the parent nucleus.
Mitosis results in formation of two daughter cells from a single mother cell.
Since mitosis occurs in somatic cells, and it leads to growth of vegetative parts.
It is also known as somatic cell division or equational division.
Segregation and recombination do not take place during mítosis.
Cell cycle The period in which one cycle of cell division is completed is called cell cycle.
It is divided in to Interphase, Mitosis and Cytokinesis.
A. Interphase: It is the longest stage of cell cycle. Generally known as DNA synthesis phase. Further divided into three sub stages.
a.G1 It is pre-DNA replication phase. Protein & RNA synthesis takes place during this phase.
b. S-phase: The chromosome and DNA replications take place during this phase.
c. G2: Post-DNA replication phase. Protein and RNA synthesis occur during this phase.
B. Mitotic phase: 1. Prophase: Chromosomes look like thin thread and uncoiled in the early prophase and become short and condensed during late prophase.
The nuclear membrane and nucleolus disappear at the end of prophase.
Prophase is the longest phase of mitosis.
2. Metaphase: Nucleolus disappear.The spindle tubes are formed and chromosomes are oriented in the centre at equatorial plate. Shortest and thickest state of chromosomes. Chromosomes are clearly visible at metaphase.
3. Anaphase Chromatids separate at the centromere and move towards opposite sides or pole. Chromosomes are most condensed at anaphase. It is the smallest stage of mitosis.
4. Telophase: Chromosomes teaches opposite sides. Nucleolus reappears during this phase.
C. Cytokinesis: The division of nucleus is known as karyokinesis. It is followed by division of cytoplasm, which is known as cytokinesis. Division of cytoplasm results in formation of two daughters cells.
