Portion of Chromosome Copied with Limited dTTP

[whamola411]

1. dTTP is used in DNA synthesis. dTTP concentrations are mM, while a particular chromosome has only two copies. Estimate what fraction of the complete diploid set of chromosomes will be copied if at the start of DNA synthesis all new production of dTTP is blocked and the initial concentration of dTTp is 1 mM.
Several estimates need to be made. Explain where the estimates come from.



2. I don't have any relevant equations. This problem has no correlation to what we are learning in class, other than we are just starting to learn about DNA.



3. I started by finding out how big an average chromosome is and got 150*10^6 bp of 3*10^8 bases. Then I found the molar weight of dTTP to be 482.168 g/mol. I also found online that an average nucleotide weighs about 330 g/mol. Then I divided the total number of nucleotides by the MW for one nucleotide: 3*10^8/330 = 9.09*10^5 g/mol of nucleotides in one chromosome pair.

From here I don't know where to go because of the mM. The fact that there is a liter in the units throws me off completely.

 

[Ygggdrasil]

First, you need to estimate the size of the cell in order to figure out how many moles of dTTP are in the cell.

 

[whamola411]

Well, a typical cell is around 1 micrometer, or .001 mm. So, if we need volume, I would assume a cell to be roughly square and the volume to be .001*.001*.001 = 1*10^-9 mm^3