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.

blood enters the heart through two large veins, the inferior and superior vena cava, emptying oxygen-poor blood from the body into the right atrium of the heart. as the ventricle contracts, blood leaves the heart through the pulmonic valve, into the pulmonary artery and to the lungs where it is oxygenated.