The Student Room Group

Could someone please explain Meiosis in a simple way but at AS level...

My textbook is just a piece of... It doesn't explain anything. :/

It shows a diagram with two paternal homologues and two maternal homologues in Interphase. I know that DNA has been replicated so I know there should be two chromosomes but why is there a maternal and paternal? Am I right in thinking that paternal is sperm and maternal is an ovum? If so, why are they there? :|

Also I'm getting confused between chromosomes, DNA and chromatids.
I know DNA is coiled up in a chromosome, but why does it form that X shape? Is each 'line' of the X meant to each have 23 chromosomes or something?

Ugh, I hate Biology.
Check biologymad.com - what board are you on?
Reply 2
Original post by LeaX

It shows a diagram with two paternal homologues and two maternal homologues in Interphase. I know that DNA has been replicated so I know there should be two chromosomes but why is there a maternal and paternal? Am I right in thinking that paternal is sperm and maternal is an ovum? If so, why are they there? :|


Paternal = Father
Maternal = Mother

You know that you have 23 of your fathers chromosomes and 23 of your mothers chromosomes... Therefore each pair of homologous chromosomes you have from both parents line up next to each other and then one of each pair goes in to the gamete cell... meaning the gametes will contain half the number of chromosomes.

What do you mean by?
Original post by LeaX
Is each 'line' of the X meant to each have 23 chromosomes or something?



Original post by LeaX
Ugh, I hate Biology.


I hate it too... Bye. :mad:
Original post by LeaX
My textbook is just a piece of... It doesn't explain anything. :/

It shows a diagram with two paternal homologues and two maternal homologues in Interphase. I know that DNA has been replicated so I know there should be two chromosomes but why is there a maternal and paternal? Am I right in thinking that paternal is sperm and maternal is an ovum? If so, why are they there? :|

Also I'm getting confused between chromosomes, DNA and chromatids.
I know DNA is coiled up in a chromosome, but why does it form that X shape? Is each 'line' of the X meant to each have 23 chromosomes or something?

Ugh, I hate Biology.


Each X is a chromosome, and you have 23 for a haploid(half set) cell, and 46 in a diploid(full set) cell.

Each chromosome is made up of genes which code for the production of proteins and enzymes (which in essence are proteins), by coding for the sequence of amino acids.

When a paternal and maternal haploid nuclei fuse, they create a cell with a diploid number (a full set of chromosomes)

Meiosis has already taken place beforehand in creating the gametes (sex cells).

Quick Reply