Ch8.2 The Discovery of DNA as the Genetic Material

Griffith, Avery, and Hershey/Chase all performed important experiments that helped us discover that the genetic material that stores hereditary information is encoded in ______.

• Protein

• Lipids

• DNA

• Ribosomes

Hershey and Chase did their DNA studies on viruses that infect bacteria, called __________________

• Bacteriophages

• Influenza

• Staphylococcus

• r-strains

Hershey and Chase used the radioactive elements phosphorous and sulfur to study how bacteriophages infect bacteria. These elements were chosen because the element ______________ is

only found in DNA and the element _______________ is only found in protein.

• phosphorous; sulfur

• sulfur; phosphorous

The strain of staphylococcus bacteria that can cause pneumonia (pathogenic)

• r-strain

• s-strain

• both

• neither

The scientist(s) that first discovered bacterial transformation

• Watson and Crick

• Griffith

• Avery

• Hershey and Chase

What is the structural difference between r-strain and s-strain staphylococcus?

• the r-strain has a capsule and the s-strain does not.

• the s-strain has a capsule and the r-strain does not.

• the r-strain has DNA and the s-strain does not.

• the s-strain has DNA and the r-strain does not.

Griffith's transformation experiments proved that DNA was the genetic material without a doubt.

• True, he showed DNA was the genetic material

• False, he only proved that there was a transformative material, but could determine if it was protein or DNA

• False, his results were inconclusive and didn't get us any closer to discovering the genetic material

In Griffith's experiment, what was the result of injecting dead s-strain and live r-strain bacteria into a mouse?

• The mouse died and live s-strain was recovered from the blood

• The mouse lived

• The mouse died and live r-strain was recovered from the blood

In short, what is bacterial transformation?

• The process by which bacteria can pass genetic information to one another...even when dead

• The process of converting bacteria into viruses

• The process of converting viruses into bacteria

• The process by which bacteria turn pathogenic

In short, how did Avery's experiments differ from those of Griffith?

• Avery performed the same experiments but he selectively removed specific organic molecules each time to determine which of them was the transforming molecule.

• Avery used viruses instead of bacteria

• Avery performed very similar experiments but he infected a different organism rather than mice.

• Avery's experiments were inconclusive whereas Griffith's definitely showed that DNA was the genetic material.