You are given cell stock A. After you load and count, the average number of cells in one counting square is 35. Now you can use this number to calculate the concentration of this cell stock. The concentration is

You have a cell count of 6.7 x 10° cells / ml in a total volume of 4.5ml. You have resuspended your cells in 5ml sterile PBS. You need to seed a six-well plate with the following numbers: a. 2 wells at 1 x 10“ cells / well (2ml / well) b. 2 wells at 4 x 10 cells / well (2ml / well) c. 2 wells at 2 x 10° cells / well (2ml / well) Determine the volume of the original culture you will need to seed each concentration.

You collected 1000 mL of river water from the stream running through campus. You prepared dilutionsof the water as follows:Tube A. 0.5 mL of river water + 99.5 mL of sterile waterTube B. 1 mL from Tube A + 9 mL of sterile waterTube C. 1 mL from Tube B + 9 mL of sterile waterTube D. 1 mL from Tube C + 9 mL of sterile waterYou then plated 0.1 mL of each dilution onto each of three MacConkey agar plates. (MacConkey agar is type of selective,differential medium. It inhibits the growth of Gram-positive microorganisms and non-enteric Gram-negative bacteria.Among the bacteria not inhibited by the medium, lactose-fermenting bacteria form pink colonies and bacteria that do notferment lactose form colorless colonies.) After incubation, the colonies were too numerous to count on the platesprepared from dilutions A, B, and C. For the plates prepared from dilution D you counted the following numbers ofcolonies:Plate 1: 155 pink colonies and 50 colorless coloniesPlate 2: 165 pink colonies and 55…

You collected 1000 mL of river water from the streamrunning through campus. You prepared dilutions of the water as follows:Tube A. 0.5 mL of river water + 99.5 mL of sterile waterTube B. 1 mL from Tube A + 9 mL of sterile waterTube C. 1 mL from Tube B + 9 mL of sterile waterTube D. 1 mL from Tube C + 9 mL of sterile waterYou then plated 0.1 mL of each dilution onto each of three MacConkey agarplates. (MacConkey agar is type of selective, differential medium. It inhibitsthe growth of Gram-positive microorganisms and non-enteric Gram-negative bacteria. Among the bacteria not inhibited by the medium,lactose-fermenting bacteria form pink colonies and bacteria that do notferment lactose form colorless colonies.) After incubation, the colonieswere too numerous to count on the plates prepared from dilutions A, B, andC. For the plates prepared from dilution D you counted the followingnumbers of colonies:Plate 1: 157 pink colonies and 62 colorless coloniesPlate 2: 167 pink colonies and 67…