Meiosis

What is the starting cell in meiosis? Like it can't be a gamete because gametes have 23 chromosomes whereas the starting cell has 46 chromosomes. I mean before interphase.

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A diploid cell

Original post by Muserock

A diploid cell

What type of cell though? From my understanding, diploid means total number of chromosomes so a cell with its total number of chromosomes.

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Original post by foxstudy

What type of cell though? From my understanding, diploid means total number of chromosomes so a cell with its total number of chromosomes.

The gamete mother cell is diploid. What are you unclear about here?

Reply 6

foxstudy

Original post by Bio 7

The gamete mother cell is diploid. What are you unclear about here?

I don't understand how though because gametes that arise after meiosis cell division have 23 chromosomes ?

Reply 7

Bio 7

Original post by foxstudy

I don't understand how though because gametes that arise after meiosis cell division have 23 chromosomes ?

That's because they are pulled apart to make gametes.

The chromosomes replicate, they are pulled apart to make diploid cells still. Then the next set of cells made are haploid as no replication occurs.

Reply 8

foxstudy

Original post by Bio 7

oh wait is the cell that is dividing by meiosis a zygote ? when the gametes (ovum and sperm cell) join ?

Reply 9

Bio 7

Original post by foxstudy

oh wait is the cell that is dividing by meiosis a zygote ? when the gametes (ovum and sperm cell) join ?

A fertilised egg is a zygote. The cell to begin meiosis is a gamete mother cell.

Reply 10

foxstudy

Original post by Bio 7

A fertilised egg is a zygote. The cell to begin meiosis is a gamete mother cell.

but gametes have 23 chromosomes ? and the starting cell has 46 chromosomes. I feel so stupid because this is GCSE stuff.

Reply 11

Bio 7

Original post by foxstudy

but gametes have 23 chromosomes ? and the starting cell has 46 chromosomes. I feel so stupid because this is GCSE stuff.

The chromosomes replicate but don't separate at the centromere, so still joined in the classic shape. These line up on the metaphase plate and are pulled apart by spindle fibres to the poles. Each pole becomes a new cell. Each new cell is diploid because there are 23 chromosomes that are joined together, also counting as 46. This process repeats but this time the Chromatids are pulled apart to the poles to make 2 new haploid cells. 4 new cells in total from one gamete mother cell.

Reply 12

foxstudy

Original post by Bio 7

But in the starting cell, doesn't one chromosome come from the mother and the other comes from the father ?

Reply 13

Bio 7

Original post by foxstudy

But in the starting cell, doesn't one chromosome come from the mother and the other comes from the father ?

Are you aware of what a zygote is? Because it has nothing to do with meiosis.

Reply 14

foxstudy

Original post by Bio 7

Are you aware of what a zygote is? Because it has nothing to do with meiosis.

Zygote is a fertilized egg/ovum cell? Yea I just realised they divide by mitosis. So meiosis is the division of sex cells or gametes such as the sperm cell and ovum/egg cell ? what exactly is the diploid number of the starting cell?

Reply 15

foxstudy

Ahh that makes more sense. How does the starting gamete have 46 chromosomes then?

Reply 16

foxstudy

wait so the starting cell has 46 chromosomes, then the DNA replicates so it has 92 chromosomes during interphase, then it divides into two cells where each has 46 chromosomes, then the cell divide again into 4 cells with 23 chromosomes ?

Reply 17

Bio 7

Original post by foxstudy

Yes. But as the 96 are still joined at the centromere you can call it a single chromosome untilnit separates.

Reply 18

foxstudy

oh shoot I meant that this is GCSE stuff and I should already know it. I'm doing a levels now. How many chromosomes does the gametes mother cell have before replication?