Homework 7

Homework -7 Due oct 30 th 10 points s Answer the following questions and upload a file with answers. 1. In the experiment you are doing with yeast in lab 7 and 8, the O.D of a WT yeast cell culture is 1.24 . You made a dilutions series of this culture using 1:100 dilution from 10 -1 to 10 -5 dilutions. a. How much culture would you take to make a 1:100 dilution in the 10 -1 tube, if the final volume is 200 ul. (1 point) b. You added 5 ul of each of the concentration to the YPD plate and incubated it at 30C for two days. To your surprise, you only see colonies in 10 -1 and 10 -2 dilutions and not for the remaining dilutions. List two reasons to not see colonies in on the plate from this culture. (2 points) 2. If you were given a liquid cell culture with a concentration of 6 x 10^8 cell/mL, and asked to transfer 200µL of this culture to 100mL of fresh media, how many cells would get transferred? Please, show your calculation. (2 points) 3. List two DNA repair mechanisms in yeast that were discussed during the lecture in relationship to the US sensitive mutant we used in the lab. (2 points) 4. Which part of UV radiation from the sun is unable to reach earth’s surface and why? (1 point) 5. What is the advantage of using haploid yeast cell culture over a diploid human cell culture in understanding the effect of UV radiation? (2 point) L , V , LeVa 1001V , =(1) (200) Ef : Int culture Since 10-3 and 10-4 and 10-s - are the dilutions with the lower concentrations , they contain a lower amount of colonies which makes it a 1 x 100 cell/mL (F) 1 . 2 x 108 cells greater chance for the colcies that are there to die and not be seen . photoreactivation excision repair Another reason is since there is a low concentration the yeast colonies UV-C radiation , it has the shortest wavelengths could've just not formed at all since the t is almost completely absorbed by the ozone layer to environmental protect Us . conditions for them to turive were less than A haploid yeast culture can help you easily ideal I visualize the effects of UV radiation because of their simplicitly , how easy it is to culture them , and how easily their genes can be manipulated . It will be easy to determine the genes affected by Ort which ones repair the damage -