seriously im getting so confused between meiosis 1,2 nd mitosis, please help!

Question

anonymous · Answer

Don't worry, it is quite confusing but I can run down the steps for you.

First lets remember the difference between Mitosis and Meiosis. In mitosis, the cell is literally cloning itself- this is useful in cell regeneration or healing, and growing. Meiosis on the other hand is a way for a cell to split itself into four daughter cells with non-identical DNA. 

For meiosis to happen, it first need to replicate all it's DNA which occurs in interphase. (Interphase is not a part of the Meiosis process, but is vital for Meiosis to occur) This now means all the chromosomes in the cell have duplicated themselves and now look like the X's you often see in diagrams. Both sides of this X have exactly the same DNA. Recall that each chromosome also has a homologous pair which is similar in structure. 

The main differences between Meiosis One and Two is that in Meiosis one, the homologous PAIRS line up on the metaphase plate, and the homolougous PAIRS are separated during anaphase. This results in TWO DAUGHTER cells 

I don't know if this will help you understand but this is how the chromosomes line up in Meiosis 1.

X i X
X i X

that turns into this; two daughter cells.

X                                X
X                                X

In meiosis two, this chromosome line up directly on the Metaphase plate and are separated as such..

X                                X
X                                X

turns into

I               I                                  I             I
I               I                                  I             I

Those represent the four daughter cells.

Recall: Meiosis one - Homologous Chromosome pairs line up and are separated
           Meiosis two - Attached sister Chromatids line up and are separated

anonymous · Answer

http://www.youtube.com/watch?v=D1_-mQS_FZ0

anonymous · Answer

In Mitosis, the DNA is not jumbled at all (There is not Crossing Over, or Independant Assortment) This is so the two daughter cells will be exactly the same as the parent was. In Meiosis, the DNA is jumbled (Some of it is mixed up and around) This allows for four daughter cells, that are haploid (Half the amount of DNA to be a lifefor. AKA, sperm or egg cells) Each sperm or eggs cell has unique set of DNA, not similar to one parent cell. This is why if a person has two children, they will not be identical (Unless they are identical twins of course! But thats another story)

anonymous · Answer

so meiosis is needed for reproduction and mitisis is needed for replication of cells?

aroub · Answer

yes!! :)

anonymous · Answer

thank you:-)