Drosophila melanogaster, the fruit fly, has a 2n chromosome number of 8. assuming that a somatic g2 nucleus contains about 8.0 picograms of dna, how many picograms of nuclear dna would you expect in:

a) mitotic metaphase
b) a primary oocyte (metaphase)
c) a secondary oocyte (metaphae)
d) a first polar body (metaphase)

a) Mitotic metaphase

8 picograms

b) a primary oocyte (metaphase)

8 pecograms

c) a secondary oocyte (metaphae)

4 pecograms

d) a first polar body (metaphase)

4 pecograms

Explanation:

a) In mitotic phase the chromosome numbers remains same as 8 because in this phase duplicated chromosomes align in center and separate to other poles. Therefore the amount of DNA will be 8 pecograms.

b) after the mitotic meta phase the cells divide into daughter cell with equal proportion of DNA which means each cell have 8 chromosomes. therefore they both contain 8 pecograms of DNA. The new daughter cells called as primary oocytes.

c) These primary oocytes (8 chromosomes) divides into two secondary oocyte each contain 4 chromosomes which means each cell have 4 pecograms of DNA.

d) Duplication of chromosomes occur in secondary oocyte and cell divides into polar body (4 chromosomes) and ovum (4 chromosomes). Therefore first polar body have 4 pecograms of DNA in it.

See the attachment for clarification.