Question

One copy of the human nuclear genome (i.e., the amount in a gamete’s nucleus) weighs approximately 3.5 picograms. Calculate the mass of nuclear DNA (in picograms) found in a human nucleus:

   a) during G1 ?

   b) during G2?

   c) after mitotic telophase and cytokinesis?

   d) after meiosis I?

e) after telophase and cytokinesis of meiosis II during oogenesis?

Answer 1

a) . during G1 - Cell grow in size only , so no change in nuclear genome it weight around 3.5 picograms .

b). during G2 - DNA replication take place in S phase and then G2 phase come so nuclear genome will weight around 7 picograms .

c). after mitotic telophase and cytokinesis - In mitosis , cell remain in diploid condition , then nuclear genome of each cell will weight around 7 picograms .

d). after meiosis 1 - 2 haploid cells are made after meiosis 1 so nuclear genome of each cell will weight around 3.5 picograms .

e). after telophase and cytokinesis of meiosis 2 during oogenesis - In meiosis 2 , after telophase and cytokinesis cell remain haploid because meiosis 2 is basically ' mitosis of haploid cells ' . Then nuclear genome of each cell will weight 3.5 picogram .