Question

${10}^9$ bacteria were spread on an agar plate containing penicillin. After incubation overnight at 37 ${}^0$C, $10$ bacterial colonies were observed on the plate. That the colonies are likely to be resistant to penicillin can be tested by

• A. Measuring their growth rate
• B. Observing the colour of the colonies
• C. Checking their ability to grow on another plate containing penicillin
• D. Checking their ability to cause disease

Answer 1

The correct option is C Checking their ability to grow on another plate containing penicillin

10 bacterial colonies observed on the plate. These colonies are resistant to penicillin hence they survived. These colonies can be tested for resistance by checking their ability to grow on another plate containing penicillin. Thus the correct answer is option C.