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Inside the Nucleus
Nuclei are found in cells. Inside nuclei there are chromosomes and in these chromosomes
there are genes and inside these genes there is DNA.
All cells start off with nuclei but some lose their
nuclei when they become specialized, an
example of this is in red blood cells.
In human nuclei there are 23 pairs of
chromosomes (46 chromosomes). 23 of
these chromosomes come from the egg cell
and the other 23 come from the sperm cell.
Make exact copies of itself.
Provide instructions so that the cell can
make the right proteins at the right time.
When a cell divides it has exactly the same
number of chromosomes and organelles so before a cell divides it must copy these parts.
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The diagram to the left
explains the process of
Meiosis produces gametes
which have 23
chromosomes. Sperm cells
are the male gamete and egg
cells are the female gamete.
When a sperm cell fertilizes
an egg cell it creates a zygote
which has the correct
number of chromosomes (46
chromosomes (23 pairs of
chromosomes)). Meiosis only
happens in sex organs but
starts with normal body cells.…read more