Question

In 1928, Griffith injected living S (smooth) Streptococci into mice, and the mice died. When he injected living R (rough) Streptococci into mice, the mice lived. When he injected heat-killed smooth bacteria into mice, the mice lived. What was the result when he mixed heat-killed S bacteria with live R bacteria and injected this mixture into mice?
A. The mice lived.
B. The mice died, indicating that the heat-killed S bacteria came back to life.
C. The mice lived, and living S bacteria could be obtained from the blood of the living mice.
D. The mice died, indicating that DNA replicated semiconservatively.
E. The mice died, and living S cells could be isolated from the blood of the dead mice.

Answer 1

When Griffith injected the combination of Heat-killed S bacteria and Live R bacteria into the mice, it died. Its tissue sustained the S bacteria that could further kill other mice.

Answer: Option E

Explanation:

Griffith Experiment 1928

When Frederick Griffith's experiment of transformation in 1928 concluded the fact that DNA formula can be transferred through bacteria and the process is known as transformation.

Griffith used two strains of Streptococcus Pneumoniae: type III-S (smooth) and type II-R (rough) strain. He first injected the type III S bacteria into mice that caused its death.

Then he injected type II R strain that didn't affect its life. He then used a heat-killed S bacteria that also failed to kill the mice. Now, he used a combination of heat-killed S bacteria and type II R strain which proved to be deadly for the mice.

He was able to get both types of strains from the tissues of the dead mice which became the core of the transformation concept concluded that while using the combination of type II R and heat-killed S bacteria, DNA properties of type II R got converted into type III S bacteria that caused the death of the mice and remained distinguishable in the tissues i.e. it might further cause the death of other mice. This was termed as the Transformation Process.

Answer 2

Answer:

The results of the steps performed by Griffith were that the mice died, and the living S cells could be isolated from the blood of the dead mice.

Option: (E)

Explanation:

• The experiment that was carried out by Frederick Griffith is referred to as the 'Transformation Process' because he attempted to transform the DNA properties with the help of laboratory-developed bacteria with special traits.
• The experiment resulted in the death of the mice and it was also concluded that the attributes shown by the dead mice due to the injection of bacteria were fatal for other living mice.