Mitosis
Title: Mitosis 8th January 2014 Learning question: What are the names of the stages of mitosis? Homework: Complete exam questions by Wednesday15th January Hook: What connects these pictures? (Can you write more than one word?!)
Lesson Aims (d) outline the processes taking place at the G1 and G2 points in the cycle; (e) describe the appearance of the components of the nucleus and cell during mitosis with reference to: nuclear envelope, centrioles, spindle fibres, centromere, chromatids and chromosomes;
Key words… Mitosis Prophase Metaphase Anaphase Telophase Microtubules Cytokinesis Chromatid Chromasome Centromere Centriole Diploid
Cell division All complex organisms originated from a single fertilised egg. Every cell in your body started here, through cell division the numbers are increased. Cells then specialise and change into their various roles
Mitosis Mitosis is the process by which new body cell are produced for: Growth Replacing damaged or old cells. This is a complex process requiring is to be split into different stages to understand it.
DNA ‘Blueprint of life’ Codes for all the proteins needed for life Describes that characteristics of every living thing Every cell with a nucleus contains ALL the instructions to make the organism http://www.pbs.org/wgbh/nova/photo51/me dia/journey.swf
Chromosomes Each DNA strand is split into chromosomes All sexually reproducing animals have pairs of chromosomes. One set of each pair comes from each parent Humans have 23 pairs Lions have 19 pairs African wild dogs have 39 pairs Mosquito have 3 pairs Some ferns have 500-600 pairs
This (imaginary, example) animal has just two pairs of chromosomes Red = Maternal Blue = Paternal 1p 1m 2p 2m Give out paper chromosomes and an A3 cell outline
1p + copy 1m + copy 2p + copy 2m +copy During Interphase, each chromosome replicates and produces an exact copy of itself: 1p + copy 1m + copy 2p + copy 2m +copy Using cut out chromosomes and paperclips, get students to produce tetrads as above
There are four stages to Mitosis Prophase Metaphase Anaphase Telophase Remember though that this is a continuous process P M A T
Interphase Standard condition of cell DNA replicates Cell enters reproductive cycle with 2 copies of each chromosome
Prophase DNA super coils and chromosomes become visible Nuclear membrane breaks down Centrioles migrate to poles
Metaphase Chromosomes line up centromeres on equator of cell Centrioles form spindles
Anaphase Spindles ‘grip’ centromeres and chromosomes migrate to poles
Telophase Nuclear membranes reform Chromosomes disperse Cytokinesis begins
Interphase Both daughter cells are exact copies of the parent cell
INTERPHASE MITOSIS
Stages of Mitosis http://www.cellsalive.com/mitosis.htm
In humans, each cell (except sex cells) has how many chromosomes After mitosis, how many daughter cells are produced? _______. After mitosis (in a human cell), each daughter cell has how many chromosomes? _____ How many phases are in MITOSIS? ___________ Which phase of the cell cycle is the longest? _________ During which phase does cytokinesis begin? __________ What cell parts migrate to the poles during prophase? __________________. What structure holds the two chromatids together? ____________________ During which phase does the nuclear membrane dissolve? __________________ What structure moves the chromosomes into position and then pulls them apart? ___________________ What is the overall purpose of mitosis? _________________________ Complete textbook Q1-3
Welcome back Which stage?
Lesson Aims (d) outline the processes taking place at the G1 and G2 points in the cycle; (e) describe the appearance of the components of the nucleus and cell during mitosis with reference to: nuclear envelope, centrioles, spindle fibres, centromere, chromatids and chromosomes;