MIC 103L Exam 2 Page 56. Your Semi-Lucid Lab Partner asks you, "How many Yeast Cells are there in a Yeast Colony growing on a YGC Plate?" You use a Hemocytometer that has two Counting Chambers, each of which is divided (like “Hollywood Squares”) into 9 Large Squares (1.0 mm x 1.0 mm). The Centermost Large Square is subdivided into 25 Medium Squares (0.2 mm x 0.2 mm; 5 Squares across and 5 Squares down). Each Medium Square is in turn subdivided into 16 Small Squares (you ignore these guys). A Special, Thicker-than-Normal Cover Slip creates a Vertical Distance of 0.1 mm between the Top of the Counting Chamber and the Bottom of the Cover Slip. You sterilize your Loop and scoop-up all of a small, isolated Yeast Colony to make a Yeast Suspension in exactly 5.0 ml of Sterile Saline. You use this Suspension to load your Hemocytometer. The Center-most Square -- which fills your Field of View under the Yellow 10X Lens -- is marked-off into 25 Medium Squares (0.2 mm x 0.2 mm).You count the Number of Yeast Cells in 4 of these 25 Medium Squares (the Medium Squares in each Corner). Your Counts are: 47, 36, 45 and 32. Approximately how many Yeast Cells were there in this entire small, isolated Yeast Colony that you scooped-up to make your Yeast Suspension?
_______________________________________ B. 3.2 x 107Yeast Cells_______________________________________ C. 4.0 x 107Yeast Cells_______________________________________ D. 5.0 x 107Yeast Cells