Question

Why is polyploid important during meiosis (metaphase 1)?

Answer 1

The end result of meiosis is four cells, each with half the normal genome (alternatively this could be written as four haploid cells). Hence there is a need for replication of the original germ cell chromosomes ie at this stage the cell goes from diploid to polyploid (2n to 4n and at the end of meiosis 4 cells, each with n)

Answer 2

@ebaxter01 What does "n" mean in "2n" and "4n"?

Answer 3

@ebaxter01 so do you mean that polyploid is important during the meiosis because it helps the replication of the original germ cell chromosomes?
sorry but I am still confused..:( I just started biology and I am lost..:(

Answer 4

Good question: it's the number of chromosomes so in humans it's 23 pairs - this is where you get 46 chromosomes in a normal cell. An egg would have 23 chromosomes whereas a cell which had just divided might have 92 chromosomes (4n).

Answer 5

I only just got your other question: what I meant was that without this initial replication, there wouldn't be enough sets of chromosomes to go into 4 different cells. Is this ok for you now - I can get back to you otherwise

Answer 6

@ebaxter01 ah...I would really appreciate it if you could explain this a little bit more easier..;)

Answer 7

Sorry I'm using some tricky terms: polyploid means having more chromosomes than normal, so instead of 23 pairs (46) there are more - in a cell that has replicated it's chromosomes that would be 92 in total. Germ cells are the ones which make eggs or sperm (these are known as gametes) and so they have to replicate their chromosomes (that is they have to make another set). The cells will then divide and divide again to make 4 cells.

Each of these cells (gametes) will have half of a full set of chromosomes. This is so they can combine with another set when the egg is fertilized and have a full set again, but with half the chromosomes from one parent and the other half from the other parent.

Answer 8

@ebaxter01 omg!! I understood that part now!! thank you!!!!
um ok so now that I understood the first part, where does the polyploid come in?

Answer 9

@ebaxter01 I don't get the importance of polyploid.. but I understood the part:
without a replication of the original germ cell chromosomes, the cell won't go from diploid to polyploid.

Answer 10

Polyploid describes the cell with twice the normal complement of chromosomes, so now the germ cell can divide twice to give four cells, each with half a set of chromosomes. If the cell were not polyploid then there would not be enough DNA for four cells. I hope this clears it up?