{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

The Search to Identify the Genetic Material

The Search to Identify the Genetic Material - S strain...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
The Search to Identify the Genetic Material Discovery of Nucleic Acids - Friedrich Miescher, 1869 Miescher isolated the nuclei of white blood cells obtained from pus cells. His experiments revealed that nuclei contained a chemical that contained nitrogen and phosphorus but no sulfur. He called the chemical nuclein because it came from nuclei. It later became known as nucleic acid. Proteins Produce Genetic Traits - Archibald Garrod, 1909 Garrod noticed that people with certain genetic abnormalities (inborn errors of metabolism) lacked certain enzymes. This observation linked proteins (enzymes) to genetic traits. Genetic Material can Transform Bacteria - Frederick Griffith, 1931 When Streptococcus pneumoniae (pneumococcus) bacteria are grown on a culture plate, some produce smooth shiny colonies (S) while others produce rough colonies (R). This is because the
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: S strain bacteria have a mucous (polysaccharide) coat, while R strain does not. Mice infected with the S strain die from pneumonia infection but mice infected with the R strain do not develop pneumonia. Griffith was able to kill bacteria by heating them. He observed that heat-killed S strain bacteria injected into mice did not kill them. When he injected a mixture of heat-killed S and live R bacteria, the mice died. Moreover, he recovered living S bacteria from the carcasses. He concluded that some substance needed to produce the mucous coat was passed from the dead bacteria (S strain) to the live ones (R strain); they became transformed . This must be due to a change in the genotype associated with the transfer of the genetic material....
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online