Question

When Griffith injected mice with living IIR (not disease-causing) and heat killed IIIS (disease-causing) bacteria, he found that the mice died of pneumonia. What kind of bacteria did he then isolate from the dead mice that suggested transformation had occurred?

Answer 1

The correct answer is: Living IIIS (disease causing) bacteria.

Step-by-step explanation:

• According to the question, Griffith injected two strains of bacteria in the mice, which are:

1. Living IIR strain which are incapable of causing any disease.
2. Heat killed IIIS strain that can cause a disease.

• Inside the injected mice,the heat killed IIIS (disease-causing) strain of the bacteria releases a factor that was not affected by heat.
• This factor was taken up by the living IIR (not disease causing) bacteria. This caused it to get transformed from the non-disease causing IIR strain to the disease causing IIIS strain.
• After the process of transformation, the disease causing IIIS strain causes pneumonia in the mice and hence kills it.
• This factor is now known to be the DNA or Deoxyribonucleic Acid.