B6 culturing microorganisms practical

Question 1

suggest why agar plates must not be airtight when incubating

Question 2

suggest why the discs should be spread evenly around the plate and not positioned next to each other

Question 3

three discs had a circular clear zone of 17, 19 and 20 mm in diameter. calculate the average area of clear zone for the antiseptic

Answer 3

average diameter = 46/3 = 18.67
area of circle = pi x r(squared)
r=18.67/2=9.3
area of clear zone = pi x 9.3(squared) = 274mm(squared)