http://www.ebsi.co.kr/ebs/lms/lmsx/retrieveSbjtDtl.ebs?sbjtId=S20180001026 /mnt/1T-5e7/mycodehtml/Biology/CSByun/Bio1_2020/006_Chromosome_and_genetic_materials_002/main.html ================================================================================ Karyotype: appearance-characteristic of chromosome, such as, number of chromosome, shape of chromosome, size of chromosome ================================================================================ Biological entity Number of chromosome in the one cell ================================================================================ Different spicies have different karyotype (number of chromosome, shape of chromosome, size of chromosome) More precisely, same spicies and same sex have same karyotype (number of chromosome, shape of chromosome, size of chromosome) ================================================================================ Nuclear phases Nuclear phases of somatic cell: 2n Nuclear phases of germ cell: n ================================================================================ Cell division - mitosis: 2n $$$\rightarrow$$$ 2n - meiosis: 2n $$$\rightarrow$$$ n ================================================================================ Nuclear phases (see if there are couples, if they are couples): 2n 8 number of chromosome therefore, 2n=8, "before DNA replication" If this is 8 quantity of DNA ================================================================================ 2n=8, "after DNA replication" this is 8*2 quantity of DNA ================================================================================ - There is no couple, so nuclear phases is n - n=4 - germ cell after meiosis - relative DNA quantity is $$$\dfrac{8}{2}$$$ ================================================================================ Ratio of DNA relative quantity 8:16:4 = 2:4:1 ================================================================================ Male chromosome 1 to 22: autosome Female chromosome 1 to 22: autosome Karyotype of "Male chromosome 1 to 22" = Karyotype of "Female chromosome 1 to 22" ================================================================================ There are couple, so, nuclear phases is 2n There are 46 number of chromosome, so, you can write, 2n=46 More precisely, you can write 2n=44+XY ================================================================================ - Nuclear phases of sperm cell: n - Possible cases of sperm cell n=22+X n=22+Y ================================================================================ - Nuclear phases of ovum cell: n - Possible casse of ovum cell n=22+X ================================================================================