Question

You find a way to attach either a red or green fluorescent dye to nucleotides. Double-stranded DNA molecules with both strands labeled red fluoresce red, those with both strands labeled green fluoresce green, and those with one strand labeled red and the other green fluoresce yellow. You grow human cells in the presence of "red" nucleotides until both DNA strands of all chromosomes fluoresce red. You then allow one round of DNA replication in the presence of "green" nucleotides Continuing your experiment with "red" and "green" labeled chromosomes, you allow cells with DNA labeled "red" in both DNA strands to undergo two rounds of DNA replication in the presence of "green" nucleotides. What pattern of fluorescence would you expect to see in the sister chromatids of each chromosome?

Answer 1

After two rounds of replication with initial red DNA and subsequent green nucleotides, chromosomes would exhibit a pattern of half green and half yellow sister chromatids.

Step-by-step explanation:

When human cells that have DNA labeled in red undergo two rounds of DNA replication in the presence of green nucleotides, the pattern of fluorescence you would expect is varied. After one round of replication, each chromosome would consist of one red strand and one green strand, resulting in these chromosomes fluorescing yellow. Completing a second round of replication, you would expect each chromosome to have one strand from the previous yellow pair (red) and a new green strand from the second replication round. This would result in sister chromatids with one being red-green (yellow) and the other being green-green (green). So, the fluorescence pattern would be half green and half yellow sister chromatids within each chromosome.

Answer 2

Both chromatids yellow

Step-by-step explanation:

A chromatid is one duplicate of a recently replicated chromosome which is as yet joined to the first duplicate by a solitary centromere. Its principle capacity is found in the little league it stays existent, in mitosis and meiosis, as it serves to keep the best possible DNA tally where it should be.