CELL DIVISION - PART - 1.pptx

It explain the Mitotic cell division in detail with the images

1. CELL DIVISION - PART -1 DR. C. BEULAH JAYARANI M.Sc., M.A, M.E d , M.Phil ( Edn ), M.Phil (ZOO), NET, Ph.D ASST. PROFESSOR, LOYOLA COLLEGE OF EDUCATION, CHENNAI - 34 6/13/2021 Dr. C. Beulah Jayarani 1

2. CELL DIVISION A Parent cells divides into two daughter cells is called CELL DIVISION or CELL REPRODUCTION . 6/13/2021 Dr. C. Beulah Jayarani 2

3. What is cell division means? 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 reproduce 6/13/2021 Dr. C. Beulah Jayarani 3

4. Why is a cell division? 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 . 6/13/2021 Dr. C. Beulah Jayarani 4

5. TYPES OF CELL DIVISION The three types of cell division that occur in animal cells are : MITOSIS - Indirect Division MEIOSIS - Reduction Division AMITOSIS - Direct Division 6/13/2021 Dr. C. Beulah Jayarani 5

6. What are THE functions of cell division? Cellular division  has three main  functions : (1) the reproduction of an entire unicellular organism, (2) the growth and repair of tissues in multicellular animals, and (3) the formation of gametes (eggs and sperm) for sexual reproduction in multicellular animals. 6/13/2021 Dr. C. Beulah Jayarani 6

7. What is direct cell division? 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 6/13/2021 Dr. C. Beulah Jayarani 7

8. WHAT IS CELL CYCLE? 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. 6/13/2021 Dr. C. Beulah Jayarani 8

9. What IS CELL CYCLE? 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. 6/13/2021 Dr. C. Beulah Jayarani 9

10. 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). 6/13/2021 Dr. C. Beulah Jayarani 10

11. MITOSIS Fleming in 1879 Equational Division 6/13/2021 Dr. C. Beulah Jayarani 11

12. PROCESS OF MITOSIS Consists of two events, they are Karyokinesis 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 6/13/2021 Dr. C. Beulah Jayarani 12

13. PROCESS OF MITOSIS Karyokinesis consist of four phases, they are Karyokinesis PROPHASE METAPHASE ANAPHASE TELOPHASE 6/13/2021 Dr. C. Beulah Jayarani 13

14. PROPHASE Short and thick Centrosome splits Spindle fibres Nuclear membrane and Nucleolus 6/13/2021 Dr. C. Beulah Jayarani 14

15. METAPHASE Equatorial plane Attached with spindle fibre by centromere The centromere of each chromosomes divides into two, each associated with a chromatid. 6/13/2021 Dr. C. Beulah Jayarani 15

16. ANAPHASE Separate and migrate Contraction of spindle fibres 6/13/2021 Dr. C. Beulah Jayarani 16

17. TELOPHASE Becomes Chromatin threads Spindle fibres disappear Nuclear membrane and Nucleolus reappear. 6/13/2021 Dr. C. Beulah Jayarani 17

18. 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. 6/13/2021 Dr. C. Beulah Jayarani 18

19. Nerve cells do not undergo cell division due to the absence of centrioles ,but they are developed from glial cells. DO YOU KNOW ???? 6/13/2021 Dr. C. Beulah Jayarani 19

20. REFERENCE “SCIENCE READER” Tamil Nadu text book NCERT Books Google Images 6/13/2021 Dr. C. Beulah Jayarani 20