10 Questions: Chapter 1. (1 point) In the key transformation experiment performe
ID: 189914 • Letter: 1
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10 Questions: Chapter 1. (1 point) In the key transformation experiment performed by Griffith, mice were injected with living IIR bacteria mixed with heat-killed IIIS bacteria. a. What happened to the mice? What type of bacteria were recovered from the mice? What is the molecular explanation of this result? b. What result would you expect if living IIIR bacteria had been mixed with heat-killed IIS bacteria? Explain why, for Griffith to interpret his results as evidence of transformation, it was necessary for him to mix living IIR bacteria with dead IS bacteria and not with dead IIS bacteria.Explanation / Answer
a. The mouse died. Both live II-R and live III-S strains of pneumococcus were recoverd from the blood of these dead mice. As per Griffith, the the type-II R strain was converted into the lethal type II-S by a 'transforming principle' present in the dead IIIS. This transforming principle was the DNA. which had survived during the heating process and was taken up by the II-R.
b. The living IIIR bacteria would have taken up the DNA of the virulent heat killed IIS and all the mice would have died.
c. To rule out the effect of mutation Griffith had to use to IIR and IIIS. because conversion from IIR to IIS could also coccur due to mutation but IIR to IIIS was only possible by the presence of some transforming agent like DNA ,
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