2. Bacteriophages Flashcards
What are the characteristics of the genetic material?
The genetic material contains information in a stable form regarding cell structure, function, development and reproduction.
Accurate replication is important, so the progeny of the cells have the same genetic information as the parental cell.
Genetic material is capable of changing through mutations. This is essential for genetic variation, adaptation and evolution.
What is the Griffith’s transformation experiment (1928)?
The first experimental approach was to analyse the physical nature of the hereditary material. This required the use of 2 strains of the bacteria streptococcus pneumoniae which is responsible for pneumonia.
The two strains were:
- > S strain which has a polysaccharide coat and appears smooth in nature. The virulence of this strain is highly infectious.
- > R strain which appears rough and is known to be avirulent and therefore harmless.
Describe the two S-strains Griffiths worked with.
The two s-strains he worked with were the IIS and the IIIS strains. They both differ in chemical composition regarding the polysaccharide coat. But also, the s-strains can generate R-strains in vitro.
