Question

1. What experiments did Fred Griffith do and how does later work demonstrate DNA as the genetic material?

2. What is the function of “Mobile DNA elements”, how might it contributed to the evolution of higher organisms?

3. Study the structural organization of the chromosome, chromatin and nucleosome and understand key concepts.

Answer 1

1) While working with Streptococcus pneumoniae (the bacterium that causes pneumonia) in 1928, Frederick Griffith watched an inexplicable change in this bacterium. When you develop this bacterium on a culture plate, some produce gleaming states (meant as 'S') and some produce unpleasant settlements (meant as 'R').

The S strain microorganisms have a polysaccharide coat which offers ascend to smooth, gleaming states. The R strain does not have this coat and thus, it gives harsh provinces. Additionally, the S strain is harmful and causes pneumonia; while the R strain is non-destructive. He played out the accompanying analysis with these strains and saw distinctive perceptions.

S strain → Inject into mice → Mice create pneumonia and bite the dust.

R strain → Inject into mice → Mice live.

Warmth murdered S strain → Inject into mice → Mice live. (Griffith found that warming executes the microscopic organisms).

Warmth murdered S strain + R strain → Inject into mice → Mice kick the bucket.

hereditary material

Frederick Griffith's analysis

Perceptions – Not just did the mice infused with the warmth murdered S strain + R strain kick the bucket, yet Griffith likewise recouped live S strain microbes from these dead mice.

Conclusions – He reasoned this was on the grounds that the R strain had some way or another been 'changed' by the warmth slaughtered S strain. This he contended was because of the exchange of a 'changing guideline' from the S strain to the R strain, which made the R strain harmful. Albeit critical, his perceptions did not recognize the biochemical idea of the changing guideline.

Please post other questions separately