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Asked by anon-220358 on 12 Jun 2019.
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Rebecca Moon answered on 12 Jun 2019:
Its a form of chromosomal replication to give two identical nuclei with the same number of chromosomes as the original nuclei. As opposed to meiosis which gives half the number of chromosomes. But I could not tell you what the phases of mitosis and meiosis are called now – I definitely knew it once, but it is not really something I work with now so it’s been packaged into some distant memory!
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Rachel Hardy answered on 12 Jun 2019:
Mitosis is when a cell divides to form two identical copies of its original self. Before this can happen, the DNA found within our cell nuclei must replicate (i.e. form another copy). This process ensures that each new cell receives a complete molecule of DNA. Mitosis happens more in certain cells of the body than others. For example, skin cells constantly needs to divide to replace dry and dead cells that are lost from the surface each day. This is a contrast to cells in organs such as the liver, which rarely undergo mitosis. In fact, liver cells do not need to be replaced unless they are exposed to stress. A good example is when humans drink too much alcohol. This damages liver cells, meaning that they must undergo mitosis to make new healthy cells. Check out these links if you would like to read more on the specifics of each stage of mitosis: https://www.thoughtco.com/stages-of-mitosis-373534
https://sciencing.com/5-stages-mitosis-13121.html -
Deepak Chandrasekharan answered on 13 Jun 2019:
Mitosis is a way in which cells divide and one cell gives two identical cells. In humans this is the way organs replace cells that we lose e.g. from the skin or in our gut.
Another form of cell division is meiosis and this how we make sperm cells and female egg cells. They only have half the number of chromosomes (how molecule of DNA are packed together and stored). Because of two processes called recombination and independent assortment – the DNA in each sperm/egg cell is unique and so when a sperm and egg combine you get a unique complete set of DNA and a unique new person!
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Nina Rzechorzek answered on 13 Jun 2019:
The descriptions below cover this well. All I would add is that the key cells in our brains – the neurons – are ‘post-mitotic’, i.e. once mature, they will not replicate themselves so the neurons that you have at your age have to last a lifetime – that’s why it’s important to look after them! Pretty cool if you think about it – my Grandad’s brain cells have been around for 96 years, and the brain cells of a mature Greenland shark may have been around for more than 300 hundred years which is amazing! This situation is unlike that of the cells in some other organs such as skin and liver which can effectively ‘regenerate’.
Now something that we are really interested in – if all cells contain their own ‘biological clock’, what happens to it when a cell divides? Are the two ‘clocks’ in time with each other?…. -
David Wilson answered on 13 Jun 2019:
yes, and it still never fails to blow my mind when i catch sight of it happening when i’m using a microscope!
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Matthew Bareford answered on 13 Jun 2019:
Yes, and it’s still one of the most memorable things to observe down a microscope (in my opinion)
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Shobhana Nagraj answered on 13 Jun 2019:
I think everyone has already answered this well! I love @Nina’s comment – didn’t know that about neurones being post-mitotic! Will take better care of mine now I do know more!
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Kate Timms answered on 17 Jun 2019:
Yep! And everyone else has told you exactly what it is. Did you know that the word comes from the Greek word from thread? Probably because during mitosis, the DNA looks for a short time like a tangle of thread!
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