Cell Division Mitosis

Mitosis Produces 2 cells – called daughter cells – from one parent cell Daughter cells are identical to each another and to the original parent cell Most body cells reproduce this way Similar to binary fission Asexual reproduction of organisms without a nucleus

Mitosis Occurs because: Multi-cellular organisms grow in size and complexity by making more cells Old and damaged cells are continuously replaced by the division of cells Single-celled organisms such as bacteria divide to make new, independent organisms Binary fission – asexual reproduction

Mitosis The nucleus of the cell divides in two The nucleus contains the genetic material – chromosomes – of the organism Chromosomes are made of DNA

Mitosis The Cell Cycle The nucleus divides in several phases: Interphase Prophase Metaphase Anaphase Telophase

Mitosis Interphase Technically not part of mitosis A resting phase DNA (Chromosomes) copies itself exactly (replicates) Organelles double in number, to prepare for division

http://www.biologycorner.com/bio1/cellcycle.html

http://www.iknow.net/CDROMs/cell_cdrom/cell3.html

Mitosis Prophase Nuclear membrane disappears Spindle fibers (or aster fibers) form at the ends of the cell Chromosomes coil up and become short and fat - become visible Takes about an hour

http://www.biologycorner.com/bio1/cellcycle.html

http://www.iknow.net/CDROMs/cell_cdrom/cell3.html

Mitosis Metaphase Chromosomes in pairs line up along the equator – middle of cell Spindle fibers attach to the center of the chromosome pairs Centromere – the connecting point of the two chromosomes Takes about 15 minutes

http://www.biologycorner.com/bio1/cellcycle.html

http://www.iknow.net/CDROMs/cell_cdrom/cell3.html

Mitosis Anaphase Chromosomes divide Chromatids (half of a chromosome pair) separate and are pulled to opposite ends of the cell by the spindle fibers Takes about 10 minutes

http://www.biologycorner.com/bio1/cellcycle.html

http://www.iknow.net/CDROMs/cell_cdrom/cell3.html

Mitosis Telophase Nuclear membrane forms around each group of chromosomes Chromosomes unwind and become long and thin again Cytokinesis begins

http://www.biologycorner.com/bio1/cellcycle.html

http://www.iknow.net/CDROMs/cell_cdrom/cell3.html

Mitosis Cytokinesis Cytoplasm divides One cell becomes two individual cells Different in plants and animals Animals: Cell membrane pinches in Plants: Cell wall forms down the center http://www.dundee.ac.uk

http://www.biologycorner.com/bio1/cellcycle.html

http://www.iknow.net/CDROMs/cell_cdrom/cell3.html

Animation http://www.johnkyrk.com/mitosis.html

Animation http://www.cellsalive.com/mitosis.htm