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Eukaryotic Cell Division. Occurs by Mitosis Q: What type of cell does mitosis occur in? A: Somatic cells or body cells (2n). The Cell Cycle. Cell cycle = period from the beginning of one cell division to the beginning of the next. Why is cell division important?. The Cell Cycle.
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Eukaryotic Cell Division Occurs by Mitosis Q: What type of cell does mitosis occur in? A: Somatic cells or body cells (2n)
The Cell Cycle Cell cycle = period from the beginning of one cell division to the beginning of the next. Why is cell division important?
The Cell Cycle Three important functions of cell division for organisms: • Growth – grow from single cell to multi-cellular organism • Maintenance – replacement of worn out cells (e.g. Blood cells) • Repair – cell division regenerates damaged tissues
Cells divide for an organism to survive Result of cell division = two new cells (daughter cells) that are identical to the original cell (parent cell) Why are the daughter cells identical? • They contain an exact copy of the parent cell’s hereditary material • DNA (deoxyribonucleic acid) • DNA store the instructions that determine the details of the organism’s life (characteristics, functions, life span)
Cells divide for an organism to survive DNA – is store in the nucleus of eukaryotic cells - it forms thread-like coils called chromatin, which we usually can’t see - when a cell divides, the chromatin condenses and forms chromosomes, which we can see
Why is cell Replication in Eukaryotes more complicated? • complicated because: • DNA is divide among several linear chromosomes • DNA is contained within a nucleus • cell has several membrane bound organelles Source: http://commons.wikimedia.org/wiki/File:Kasvisolu.png
Three Stages of the Cell Cycle • Stage 1 – Interphase • Growth and preparation of cell for division • DNA replication occurs in this stage • Consists of G1, S, G2 phases • Stage 2 – Mitosis • Division of the nucleus • Consists of 4 phases • Stage 3 – Cytokinesis • Division of the cytoplasm and organelles Growth Stage Division Stage
Spindle fibres from opposite poles attach to the centromere of each chromosome
Cleavage furrow • Division of cytoplasm (cell pinches in two) • creates a cleavage furrow