Watch [in Urdu] on: https://youtu.be/RUoL3BlPsEQ Human Cell Division -Mitosis -Meiosis

1. RADIOBIOLOGY
Human Cell Division
Rahman Ud Din
Senior Lecturer Radiology
Northwest Institute of Health Sciences

2. LEARNING OUTCOMES
 Cell Proliferation
 Cell Cycle
 Mitosis
 Prophase
 Metaphase
 Anaphase
 Telophase
 Meiosis
 Tissues and Organs

3. CELL PROLIFERATION
 An act of a cell to reproduce and multiply in number
 Human body consists of;
 Somatic cells
 Genetic cells (oogonium and spermatogonium)
 All body cells are somatic cells
 Somatic cells proliferate by mitosis
 Genetic cells undergo meiosis
 Several rad (many grays) are needed for cell damage

4. CELL CYCLE
 Geneticist see cell cycle as mitosis and interphase
 Somatic cells division by stages (mitosis);
 Prophase
 Metaphase
 Anaphase
 Telophase
 The portion of a cell cycle b/w mitotic events is called
interphase
 Interphase is cell growth b/w division
 In cell cycle; M, G1, S, G2 phases happens
 Phases are characterised by structure of
chromosomes

5. CELL CYCLE …….
 G1 is the pre-DNA synthesis phase
 This is the gap in cell growth between M and S
 S is the synthesis phase (DNA replicated in two identical
DNA daughter)
 In S, chromosomes transferred from two chromatids
(centromere in centre) to four chromatids
 Results in two pairs of homologous chromatids with
same DNA contents and structure
 G2 phase is a post-DNA synthesis gap of a cell growth

6. MITOSIS
 Chromosomes are not visible
 DNA slowly takes the shape of chromosomes
 Prophase
 Nucleus swells, DNA prominent, structural form
 Metaphase
 Chromosomes appears, lined up equator of nucleus
 Anaphase
 Splitting of chromosomes at centromere, chromatids connected by fibers
 Spindles fibers, chromosomes are half and moved towards the spindle
 Telophase
 Chromosomes into DNA, two nuclei (membrane covering), cytoplasm division

7. MEIOSIS
 Genetic material changes by division process called meiosis
 Genetic cells-somatic cells (23 pairs or 46 chromosomes)
 If genetic cells marriage to another genetic cells (must be 23)
 The union of genetic cells must result in 46
 It starts with 46 chromosomes
 Appears same at G2 phase and have completed
 Progress into two daughter cells by mitosis
 Contains 46 chromosomes of two chromatids each
 All of sub phases are same

8. MEIOSIS
 Each daughter cells progresses to second division
 All material including chromosomes are divided
 Second division not accompanied by S-phase
 No replication of DNA occurs
 No chromosomes are duplicated
 The granddaughter cells contains only 23 chromosomes
 Parent cell undergone two division
 Some chromosomal material are exchanged by crossing over
 Change in genetic constitution and changes in traits

9. TISSUES AND ORGANS
 Collection of cells similar structure and function called tissues
 Tissues are bound together to form organs
 Different organs perform same function forms organ system
 Tissues and organs of body includes stem cells and mature cells
 They are susceptible to radiation based on degree of radiosensitivity
 Assignment: Response to radiation in relation to cell type!?

10. THANK YOU