Passing on the Code
The genetic code contained in our chromosomes is of no real use unless it can be used to make new cells. The code is passed on to the new cells using either of two processes, mitosis or meiosis. Mitosis Mitosis is the process used during growth to make new cells within a plant or animal.
It is also used during asexual reproduction, in which an individual can clone itself to produce identical offspring. Humans don't make clones of themselves naturally like plants can. For example: strawberry plants send out runners.
However our body often has to make new cells to replace damaged ones or as we grow. So human cells also go through mitosis in the same way as animal and plant cells but is for growth and repair. The offspring cells have the same number of chromosomes as the parent cells, therefore they are diploid.
The process of mitosis is shown below: The DNA starts off as long strands in a soup-like mush in the nucleus. The chromosomes become clear as the DNA twists up. Each double arm (chromatid) is a copy of each other.
Chromosomes line up along the centre line and begin to be pulled apart by fibres. Membranes form about the separated chromosomes. These become nuclei of daughter cells.
The chromosomes unwind back into loose threads within the daughter cells. The single-armed chromosomes within the daughter cells replicate themselves to create the double arms (chromatids) again. See if you can sort the sentences below into the correct order.
Drag the numbers from the top bar to the sentences below: /**/ Bacterial cells also use mitosis to divide and multiply. That's why it all happens so quickly and your immune system has to struggle to cope. Memorising mitosis In the notes above, we have explained mitosis - but what if you could magically memorise all this for your exams easily?
Well, watch this - it's one of a load of brand new GCSE memorisation videos called mojo. If you like what you see, click the button below it to see even more mojo examples Show me more mojo