Cell Division (meiosis and budding), Diversity and cellular organisation

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  • Created by: Louisa
  • Created on: 16-05-13 16:56

Different organisms go through the cell cycle in differnent ways and times for example,
Animal cells are capable of mitosis and cytokinesis. this means they repair damage to most organisms by producing new cells to replace the damaged ones. Cytokinesis occurs from the outside in creating a clevage furrow.
Plant cells can only divide in this way at the meristematic region located at the root and tip. Cytokinesis occurs with the formation of a new cell across the equatorial plane
Cells of yeast undergo cytokinesis by producing a small 'bud' what nips off.

Budding
Spindle apparatus is not central but close to one edge
The cell wall and membrane develop a buldge into which one set of chromosomes is pulled while the other set remains in the main cell
During telophase the bud completes its formation and pinches off completely
The bud leaves the mother cell with most of the organelles so that it may bud again quickly
However, the bud will take much longer to grow to a size where it can begin to bud

Meiosis
Meiosis resembles mitosis in that chromosomes condense and become linked to spinkle as pairs of homolgous chromosomes but centromeres do not split at the start of anaphase.
One of each type of chromosome goes to each daughter.
So resulting gametes will not be genetically identical to eachother or to a parent cell.
So when two gametes from a different parents fuse, they create offspring with combinations of parental characteristics and have two sets of chromosomes again but half from each parent they are therefore Haploid

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