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Uploaded byBeulahJayarani
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CELL DIVISION - PART - 1.pptx

Cell division is the process by which a parent cell divides into two or more daughter cells. There are three main types of cell division: mitosis, meiosis, and amitosis. Mitosis is a process of nuclear division that results in two daughter cells with identical chromosomes to the parent cell. Meiosis involves two cell divisions and produces four daughter cells each with half the number of chromosomes of the original parent cell. Amitosis is direct cell division without chromosomes separating. The main functions of cell division are reproduction, growth and repair, and gamete formation. The cell cycle is the series of events in a cell leading to division, consisting of interphase and the mitotic phase involving prophase, metaphase, anaph

Science◦
CELL DIVISION - PART -1 DR. C. BEULAH JAYARANI M.Sc., M.A, M.Ed, M.Phil (Edn), M.Phil (ZOO), NET, Ph.D ASST. PROFESSOR,
CELLDIVISION A Parent cells divides into two daughter cells is called CELL DIVISION or CELL REPRODUCTION.
Whatiscelldivisionmeans? Cell division is the process in which a parent cell divides, giving rise to two or more daughter cells.  It is an essential biological process in many organisms. It is the means used by multicellular organisms in order to grow, replenish (repair), and
Whyisacelldivision? Cells divide for many reasons. For example, when you skin your knee, cells divide to replace old, dead, or damaged cells. Cells also divide so living things can grow. ... Organisms grow because cells are dividing to produce more and more cells.
TYPESOFCELLDIVISION The three types of cell division that occur in animal cells are : 1. MITOSIS - Indirect Division 2. MEIOSIS - Reduction Division 3. AMITOSIS - Direct Division
WhatareTHEfunctionsofcelldivision? Cellular division has three main functions: (1) the reproduction of an entire unicellular organism, (2) the growth and repair of in multicellular animals, and (3) the formation of gametes and sperm) for sexual in multicellular animals.
Whatisdirectcelldivision? Amitosis is the direct cell division. It is the simplest type of cell division in which there is no spindle formation or condensation of fibers. Nucleus is directly divided into two, e.g., bacteria
WHATISCELLCYCLE?  A cell cycle is a series of events that takes place in a cell as it grows and divides.  A cell spends most of its time in what is called interphase, and during this time it grows, replicates its chromosomes, and prepares for cell division.
WhatISCELLCYCLE? The G1 stage stands for "GAP 1". The S stage stands for "Synthesis". This is the stage when DNA replication occurs. The G2 stage stands for "GAP 2". The M stage stands for "mitosis", and is when nuclear (chromosomes separate) and cytoplasmic (cytokinesis) division occur.
INTER PHASE Resting Phase Interval Prepares for the next division - G1 phase (cell growth), followed by S phase (DNA synthesis), followed by G2 phase (cell growth).
MITOSIS Fleming in 1879 Equational Division
PROCESSOFMITOSIS  Consists of two events, they are 1. Karyokinesis 2. Cytokinesis The process by which the nucleus of the parent cell divides into two daughter nuclei is known as karyokinesis. The process by which the cytoplasm of the parent cell, divides into two daughter cells is known as cytokinesis
PROCESSOFMITOSIS  Karyokinesis consist of four phases, they are Karyokinesis PROPHASE METAPHASE ANAPHASE TELOPHASE
PROPHASE Short and thick Centrosome splits Spindle fibres Nuclear membrane and Nucleolus
METAPHASE Equatorial plane Attached with spindle fibre by centromere The centromere of each chromosomes divides into two, each associated with a chromatid.
ANAPHASE Separate and migrate Contraction of spindle fibres
TELOPHASE Becomes Chromatin threads Spindle fibres disappear Nuclear membrane and Nucleolus reappear.
DO YOU KNOW???? Cells of the eye lens , nerve cells of cerebral cortex and most muscle cells last a life time but once dead are not replaced.
Nerve cells do not undergo cell division due to the absence of centrioles ,but they are developed from glial cells. DO YOU KNOW????
REFERENCE “SCIENCE READER” Tamil Nadu text book NCERT Books Google Images