Stormragexox
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Hey guys for the question below the answer is D hence in its technically stating that the chromosomes in the cell are doubling at one point which i don't quite understand. How do the chromosomes initially double in the first place?

https://www.ocr.org.uk/Images/471872...-processes.pdf
Q5
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BobbJo
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(Original post by Stormragexox)
Hey guys for the question below the answer is D hence in its technically stating that the chromosomes in the cell are doubling at one point which i don't quite understand. How do the chromosomes initially double in the first place?

https://www.ocr.org.uk/Images/471872...-processes.pdf
Q5
There is DNA replication
https://en.wikipedia.org/wiki/Meiosis
4 is mitosis

1 is meiosis
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Stormragexox
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(Original post by BobbJo)
There is DNA replication
https://en.wikipedia.org/wiki/Meiosis
4 is mitosis

1 is meiosis
Thank you replying, so DNA replication is the reason for the the initial number of chromosomes to double from 2n to 4n
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BobbJo
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(Original post by Stormragexox)
Thank you replying, so DNA replication is the reason for the the initial number of chromosomes to double from 2n to 4n
yes it occurs during interphase
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Stormragexox
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(Original post by BobbJo)
yes it occurs during interphase
This is what i understand so far. Intitially after the whole process generally for both mitosis and meiosis there are only chromatids in the cell, the chromatids are now called chromosomes therefore the amount of chromosomes in the cell now is 2n. These cells then undergo interphase and another chromosome(previously a chromatid) is made via dna repication. Now there are 4n chromosomes. As there are now two chromatids attached to the centromere it is renamed as chromosomes. Hence now the cell has 2n chromosomes.Is my understanding correct?
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BobbJo
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(Original post by Stormragexox)
This is what i understand so far. Intitially after the whole process generally for both mitosis and meiosis there are only chromatids in the cell, the chromatids are now called chromosomes therefore the amount of chromosomes in the cell now is 2n. These cells then undergo interphase and another chromosome(previously a chromatid) is made via dna repication. Now there are 4n chromosomes. As there are now two chromatids attached to the centromere it is renamed as chromosomes. Hence now the cell has 2n chromosomes.Is my understanding correct?
Yes
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Stormragexox
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(Original post by BobbJo)
Yes
Where would the same process happen in meiosis is it after the zygote is formed or after the whole of meiosis( the final haploid cell)?
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BobbJo
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(Original post by Stormragexox)
Where would the same process happen in meiosis is it after the zygote is formed or after the whole of meiosis( the final haploid cell)?
Zygote is fertilised egg cell.

What process are you talking about
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Hammad(214508)
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zygote is mitosis... meiosis is only for gametes(sex cells) sperms and eggs
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Stormragexox
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(Original post by BobbJo)
Zygote is fertilised egg cell.

What process are you talking about
(Original post by Hammad(214508))
zygote is mitosis... meiosis is only for gametes(sex cells) sperms and eggs
Oh sorry I got myself mixed up there
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Stormragexox
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(Original post by BobbJo)
Zygote is fertilised egg cell.

What process are you talking about
So after meiosis occurs the haploid cells now have 23 chromatids (n) at the end of the process, now called chromosomes. The 23 chromatids then undergoes interphase and the same process as I said before then 46 chromosomes are present so won't the number of chromosomes be 2n instead of 4n for meiosis?
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BobbJo
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(Original post by Stormragexox)
So after meiosis occurs the haploid cells now have 23 chromatids (n) at the end of the process, now called chromosomes. The 23 chromatids then undergoes interphase and the same process as I said before then 46 chromosomes are present so won't the number of chromosomes be 2n instead of 4n for meiosis?
The link I gave earlier will clarify your doubts if you read it carefully

t is a cell which undergoes interphase, not chromatids.
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Stormragexox
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(Original post by BobbJo)
The link I gave earlier will clarify your doubts if you read it carefully

t is a cell which undergoes interphase, not chromatids.
I read through it again and I think I understand it much better now thank you XD
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