Question

IMPROVED NEUBAUER RULING You are preparing to plate yeast that you have been growing overnight in your laboratory and you want to determine the cell concentration of the culture. After diluting a small amount of culture 1:10 and loading your hemocytometer, you observe the grid pictured above with your light microscope. 12. What is the cell concentration (cells/ml) of the initial culture pictured in the hemocytometer grid above? (Count the cells on the diagram above, represented by dots) Show your work. Include all units. 144 cells x 2.500 x 10 dilution foctor = 3.6x10" cells ml 13. Using the culture in #12 above, you want to make 10 plates for UV treatment so you will need 1 ml of final plating culture (100ul of final culture per plate). Estimating that only 10% of yeast cells will survive your UV protocol, calculate the amount of initial cell culture and additional liquid media required to obtain 250 living cells/plate after UV treatment. (Hint: think about this problem in reverse. if you need 250 cells/plate after UV, how many do you need per plate before UV?) Show your work include all units 3.6X1D cell my 00 1440 cuils d els ante, CP = Scoo . Cells ImL 200 00mi 1 0 places 144 mit 1000mi-1401m 1941 mi of what? of what yeast ? YESP

can anyone help me with the last question please i did not do it correctly and I am unsure how

Answer 1

Inge 1 According to the given information. (12) volume of each large square = imm x Imm X 0.1mm - O-Imm3 = 104. now we know that icm3 = ImL so 10-4cm² = 10-4ml now number of dots (cells) in Each large sauare as A=43 , B = 28, C= 38 and D=39 50 average number of cells or dots - (43 +28+38+39)4 = 37 that means 10-4 ml of sample contain 37 cells therefore , Iml of sample will contain = 37x104 cells are we have diluted out sample into 1:10 that we means dilution factor is lo

(page 2 Hence initial concentration of cells will be = 37x10*x10 = 37x105 cells Im! (16) This problem is saying that only 10%. Of yeast cell will survive upto treatment and we need 850 cells per plate so let us assume we fritially used x number of Cells per plate, out of which only 250 survive that means 10% of x = 250 or x = {250 XIOC)/10 = 2500 cells per plate we need as we are preparing to plates so total cell we need = 2500X10 = 25000 celis. s from problem 12 we know our primary Culture Cocentration is 37x105 cells/ml so, amount of primary culture we will have to Pipette out -95000/374,05 6.75 +10°3m1=6.754 ond addil forical media will dequired = 1000-6.75 -993. 2501