MITOSIS AND MEIOSIS
MITOSIS
By: Puan Rosita Mohd Yusof Bandar Bukit Mahkota
Mitosis is a form of cell division. Involves mitosis and cytokinesis. Mitosis is the division of nucleus Cytokinesis is the division of cytoplasma. Daughter cells are identical to parent cells.
Mitosis adalah pembahagian sel. Ia melibatkan mitosis dan sitokinesis. Mitosis ialah pembahagian nukleus. Sitokinesis ialah pembahagian sitoplasma. Sel anak adalah serupa/sama dengan sel induk.
SIGNIFICANCE OF MITOSIS Increase the number of cells during growth and development. Elongation of shoot and roots Replacing dead or worn out cells Injured organs can be repaired eg liver. Regenerate the lost parts of their body eg lizards Asexual reproduction eg binary fission
KEPENTINGAN MITOSIS Menambah bilangan sel semasa pertumbuhan dan perkembangan. Pemanjangan akar dan pucuk. Menggantikan sel yang rosak atau mati. membaiki organ yang cedera eg hati. pertumbuhan semula bahagian badan yang hilang seperti cicak/tapak sulaiman. Pembiakan aseks eg belahan dedua.
CHROMOSOMES AND CHROMOSOME NUMBERS. Chromosomes carry genetic information which determine the characteristics of the organisms. DNA stores genetic information. Human contains 23 pairs of chromosomes. Homologous chromosomes are similar in shapes and sizes and carry the same type of genes. Paired chromosomes are known as diploid chromosomes
KROMOSOM DAN BILANGAN KROMOSOM. Kromosom membawa maklumat genetik yang menentukan ciri-ciri sesuatu organisma. DNA menyimpan maklumat genetik. Manusia mempunyai 23 pasang kromosom. Kromosom homolog adalah sama dari segi bentuk dan saiz dan membawa gen-gen yang sama. Kromosom yang berpasangan disebut kromosom diploid.
PROPHASE METAPHASE ANAPHASE TELOPHASE CYTOKINESIS
CHROMOSOMES ARE NOT CLEARLY VISIBLE (CHROMATIN) • DECIDES WHETHER TO CONTINUE DIVIDE • NEW ORGANELLES ARE FORMED •
REPLICATION & DUPLICATION OF DNA CONTAIN A PAIR OF CHROMATIDS JOINED BY CENTROMERE
RAPID CELL GROWTH PROTEIN SYNTHESIS FOR MITOSIS
UNCONTROLLED MITOSIS
Leukemia – mutation in the stem cells of the bone marrow.
Tumours – uncontrolled mitosis which results in the formation of a mass of abnormal cells.
Cancer - malignant tumour and can spread to other body parts.
CLONING A process of producing new individuals from a single parent cell.
Mature carrot plant
Transfer to soil
carrot are cut into small pieces (explants)
Explants are put in culture medium
TISSUE CULTURE TECHNIQUES
Transfer to another medium for shoot and root growth
Explants become callus mass of undifferentiated cells
ADVANTAGE
CAN PRODUCE PLANTS WITH DESIRABLE CHARACTERISICS OVERCOME INFERTILITY PROBLEMS MATURATION TIME IS SHORTER
DISADVANTAGE
DISEASES CAN EASILY SPREAD NO GENETIC VARIATION RISK OF EXTINCTION IS HIGH HAVE SHORTER LIFE SPAN.
MEIOSIS
By: Puan Rosita Mohd Yusof Bandar Bukit Mahkota
Chromosome Structure and Replication A chromatid is a single DNA molecule. Double-stranded chromosomes have two chromatids; normally, each one is identical to the other. The point where the two chromatids are attached is called the centromere.
CELLS THAT UNDERGO MEIOSIS: Anther - pollens Ovule – female gametes Testis – sperms Ovary - ovum The gametes are haploid in number. Meiosis is also known as reduction division. Meiosis can be divided into: 1.MEIOSIS 1: PROPHASE 1, METAPHASE 1, ANAPHASE 1 AND TELOPHASE 1. 2.MEIOSIS 2: PROPHASE 2, METAPHASE 2, ANAPHASE 2 AND TELOPHASE 2. Interphase occurs before meiosis 1 Cytokinesis occurs at the end of meiosis 1 and 2
http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free
Meiosis 1
Meiosis 2
Similarities: 1.Both are nuclear divisions 2.Spindle formation and the breaking down of nuclear membrane and nucleoli during prophase 1 and 2 3.Nuclear membrane and nucleoli are reformed during telophase 1 and 2.
MEIOSIS 1
Prior to meiosis 1
DIFFERENCES
MEIOSIS 2
INTERPHASE
No interphase prior to meiosis2
Occurs
REPLICATION/DUPLICATION
Does not occur
Occurs
CROSSING OVER
Does not occur
Chromosomes arrange at equator in pairs Is halved Does not occur At the end of meiosis 1 Two
METAPHASE CHROMOSOME NUMBER CENTROMERE SPLITS WHEN CELL IS HAPLOID NUMBER OF CELL FORMED AT THE END
Chromosomes arrange at equator singly Is maintained Occurs Throughout meiosis 2 Four
Meiosis
Mitosis
Similarities: 1.Both are nuclear divisions 2.Both involve interphase, prophase, metaphase and telophase. 3.Replication of DNA occurs during interphase in both divisions. 4.Duplication of chromosomes occurs only once in both divisions
MEIOSIS
Germ cells Produce gametes
DIFFERENCES
PROCESS OCCURS IN PURPOSE
MITOSIS
Somatic cells Growth / asexual reproduction
Occur
CROSSING OVER AND INDEPENDENT ASSORTMENT OF CHROMOSOME
Do not occur
Twice
NUMBER OF TIMES CYTOKINESIS OCCURS
Once
Four
NUMBER OF DAUGHTER CELLS FORMED
Two
Haploid
CHROMOSOMES NUMBER OF DAUGHTER CELLS FORMED
Diploid
Daughter cells differ genetically
GENETIC CONSTITUTION OF DAUGHTER CELLS
Parent/daughter same genetic
Errors in spindle threads connection can cause some diseases: 1.Down’s syndrome – trisomy 21 (3 chromosome 21) 2.Turner’s syndrome – female with XO chromosomes 3.Klinefelters’s syndrome – male with XXY chromosomes Colchicine can hinder spindle formation Mutation can cause changes in genetic information. It can be caused by UV rays, radioactive substance .(beta and gamma rays) and carcinogenic substances(sodium nitrite and afflatoxin)
TURNER’S SYNDROME
KLINEFELTER’ SYNDROME
KLINEFELTER’ SYNDROME
TQ