simple cell cycle question

[ddsshin]

hello.
I have few questions regarding to cell cycle of human.
I know human chromosome is 2n (diploid) meaning we have one exact same copy of every 23 chromosome... right??? except sex cells 👎 . and n= 23 which means there are 23 chromsomes x 2 = 46. so basically there are 23 that are exactly same... so my question is... if there are 46 and 23 are exactly same... what do you mean when they say one is from mother and the other is from father?? if 23 is from mother and 23 is from father... it can't be copy because the genes are not same!!!!

or is it true that 2n = 23 x 2 and each 23 has both mother and father's gene in here???
I thought they were 2 separate homologous pair? ???
Do maternal and paternal chromosome integrate during fertilization or just stay separate?? I am not sure...
How about independent assortment? not sure..

ANd...during the interphase, there is duplication which give rise to 96 chromosome, and during the mitosis.. it separates into half so... 46 back again right? and it goes back to interphase. What I am not sure is that we are told to have 46 chromosomes, but most of the time we have 96 chromosomes because the interphase is like 90% of cell cycle...
need clarificatoin/

Also, I don't understand why after the mitosis, we have a half chromosome that is considered as diploid, and after the meiosis 2, we still have half chromosome (chromatid) that is not considered as diploid but haploid.
Also,

Last of all, I don't know why there are homologous pair in the meiosis 1 which is 2x 23 = 46..

and there is only one chromosome in mitosis in diploid state. n=26.
it is so confusing to track just looking at the chromosomes and chromatids...

Can some one clearfy this very well?????

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[joonkimdds]

hello.
I have few questions regarding to cell cycle of human.
I know human chromosome is 2n (diploid) meaning we have one exact same copy of every 23 chromosome... right??? except sex cells 👎 . and n= 23 which means there are 23 chromsomes x 2 = 46. so basically there are 23 that are exactly same... so my question is... if there are 46 and 23 are exactly same... what do you mean when they say one is from mother and the other is from father?? if 23 is from mother and 23 is from father... it can't be copy because the genes are not same!!!!

or is it true that 2n = 23 x 2 and each 23 has both mother and father's gene in here???
I thought they were 2 separate homologous pair? ???
Do maternal and paternal chromosome integrate during fertilization or just stay separate?? I am not sure...
How about independent assortment? not sure..

ANd...during the interphase, there is duplication which give rise to 96 chromosome, and during the mitosis.. it separates into half so... 46 back again right? and it goes back to interphase. What I am not sure is that we are told to have 46 chromosomes, but most of the time we have 96 chromosomes because the interphase is like 90% of cell cycle...
need clarificatoin/

Also, I don't understand why after the mitosis, we have a half chromosome that is considered as diploid, and after the meiosis 2, we still have half chromosome (chromatid) that is not considered as diploid but haploid.
Also,

Last of all, I don't know why there are homologous pair in the meiosis 1 which is 2x 23 = 46..

and there is only one chromosome in mitosis in diploid state. n=26.
it is so confusing to track just looking at the chromosomes and chromatids...

Can some one clearfy this very well?????

23 pairs = 46 chromosomes in total = 23 from mother + 23 from father = known as homologous chromosomes.

 

[smile1234]

hello.
I have few questions regarding to cell cycle of human.
I know human chromosome is 2n (diploid) meaning we have one exact same copy of every 23 chromosome... right??? except sex cells 👎 . and n= 23 which means there are 23 chromsomes x 2 = 46. so basically there are 23 that are exactly same... so my question is... if there are 46 and 23 are exactly same... what do you mean when they say one is from mother and the other is from father?? if 23 is from mother and 23 is from father... it can't be copy because the genes are not same!!!!

Genes are not same but what is meant by being same is that the chromosomes are homologous, which means genes at any specific site on the two chromosomes determine the same trait though the alleles may differ.

or is it true that 2n = 23 x 2 and each 23 has both mother and father's gene in here???
I thought they were 2 separate homologous pair? ???
Do maternal and paternal chromosome integrate during fertilization or just stay separate??

They stay separate but stay in the same nucleus and form synapse with each other at the time of meiosis.

I am not sure...
How about independent assortment? not sure..

Independent assortment means at the time of meiosis each homologous pair separate. Now it doesnt happen that all maternal chromosomes will stay together and all paternal together. It occurs randomly. So one gamete will get each one of the homologous pair of chromosomes, but which one, paternal or maternal is not pre-decided.

ANd...during the interphase, there is duplication which give rise to 96 chromosome

not 96 chromosomes, there are total of 46*2 chromatids but chromosomes are 46 only.
, and during the mitosis.. it separates into half so... 46 back again right? and it goes back to interphase. What I am not sure is that we are told to have 46 chromosomes, but most of the time we have 96 chromosomes because the interphase is like 90% of cell cycle...
need clarificatoin/

There are 46 chromosomes only and never 96. During Interphase just the replication of chromosomes forms 2 sister chromatids which are attached at centromere.

Also, I don't understand why after the mitosis, we have a half chromosome that is considered as diploid, and after the meiosis 2, we still have half chromosome (chromatid) that is not considered as diploid but haploid.
Also,


In Mitosis only the two replicated DNA strands on each chromosome separate and no change in number of chromosomes occur while in meiosis1 the two homologous chromosomes separate which reduce the number of chromosomes to half and then the chromatids separate in second meiosis division.

Last of all, I don't know why there are homologous pair in the meiosis 1 which is 2x 23 = 46..

and there is only one chromosome in mitosis in diploid state. n=26.
it is so confusing to track just looking at the chromosomes and chromatids...

Can some one clearfy this very well?????

 

[bbwreckerz04]

The butterfly looking image you see during mitosis and meiosis one are dna that are already replicated during interphase. The 2n is only half the butterfly.