mitosis coursework

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Biology

Assessed practical

Coursework 1

Mitosis in garlic root cells

Mitosis is the division of one cell to form 2 daughter cells, mainly found useful for repairing tissue, replacing cells and is also used in asexual reproduction. Mitosis can also be named, nuclear division. Nuclear division is divided into four stages, Prophase, metaphase, anaphase, telophase. The first stage, Prophase, is where nuclear division begins. In early prophase, the centriole replicates itself and the chromosomes begin to coil up; they become shorter, thicker, stain more intensely and become much more visible. During late prophase, the centrioles move to opposite poles of the nucleus and the nuclear envelope ‘disappears’ (it breaks up into small vesicles not visible by a light microscope).  The nucleolus disappears to form parts of chromosomes.

 The second part of nuclear division is metaphase. In this stage the chromosomes line up along the equator of the spindle (in the centre of the 2 centrioles at opposite poles). Spindle fibres reach out from the centrioles and attack themselves to the chromosomes. The spindle fibres then split the chromosomes, and the cromasomes break at the centromere, both halves of each chromosome are pulled apart.

 The next phase, anaphase, is where the chromotids (two identical sister chromatids make up one chromosome) move to opposite poles. “The cromatids are pulled at the centromeres by the microtubules”  (6)

 In the last stage, telophase, the nucleolus reforms, and so does the nuclear envelope. All chromatids will have reached the poles and will now uncoil again to form chromatin. The remains of the spindle break down. Every chromatid contains one DNA molecule. The DNA will replicate itself during interphase (interphase is another part of the cell cycle, between telophase and the next prophase). Cytokinesis starts to take place, “This is division of the cytoplasm and cell into two by constriction from the edges of the cell”. (6)

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My Results

 Class results

Possible anomalies could be Dan’s telophase results, compared to the rest of the class, including my results, this number seems to be little too low. It is possible that this has occurred from misidentifying what phase the cell is going through, it can be rather difficult, sometimes, to tell whether the cell is in the late stage of slitting up, or is 2 cells. Although, the number of prophase cells seem to be quite normal.  It is possible that the slide was ...

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