First Question- Early 1900s What molecule carries genetic information?
Griffith Experiment: Background Info In 1928, Frederick Griffith was researching to try to explain how bacteria makes people get sick, studying pneumonia particularly. He isolated two strains of bacteria in mice. – S strain: smooth colonies, disease causing – R strain: rough colonies, harmless
Explanation Bacterial transformation The ability to cause disease was inherited by the offspring through genes.
Avery’s Further Studies In 1944, Oswald Avery determined that DNA was the transforming factor in bacteria by destroying proteins, lipids, carbohydrates, and some other molecules and transformation still occurred. The experiment was repeated where DNA was destroyed and transformation did not occur.
The Hershey-Chase Experiment Grew viruses containing radioactive 32 P and 35 S to use as markers. The protein coat of the virus contains almost no P and DNA contains no S. Therefore, the experiment could reveal whether the protein coat or DNA entered the bacteria cell.
DNA Replication Summary DNA must be replicated during late interphase to ensure that each cell has its own copy of DNA after division. During replication, the DNA molecule splits into two strands. Two new complementary strands are made using the original DNA strands as templates.