DNA and Genetic Material Discoveries

The video explores the discovery and understanding of DNA as the genetic material. It begins with Frederick Miescher's isolation of DNA, followed by the debate over whether DNA or proteins were responsible for heredity. Griffith's experiment suggested a 'transforming factor,' later identified as DNA by Avery, McLeod, and McCarty. Hershey and Chase's experiment provided definitive proof that DNA is the genetic material. The video concludes with questions about DNA's function and replication.

Who first isolated DNA and in what year?

• Gregor Mendel in 1865

• James Watson in 1953

• Frederick Miescher in 1868

• Rosalind Franklin in 1951

What was the main question regarding chromosomes in the early 20th century?

• Whether chromosomes were responsible for cell division

• Whether DNA or proteins were the genetic material

• Whether chromosomes were made of RNA

• Whether chromosomes could be seen under a microscope

What did Frederick Griffith discover in his experiments with Streptococcus pneumoniae?

• The concept of a transforming factor

• The role of RNA in heredity

• The existence of DNA

• The structure of proteins

In Griffith's experiment, what was the result when the rough strain was mixed with heat-killed smooth strain?

• The bacteria remained unchanged

• The mouse died

• The bacteria became non-virulent

• The mouse lived

What was the main conclusion from Avery, McLeod, and McCarty's experiment?

• Proteins are the genetic material

• Chromosomes are made of lipids

• DNA is the transforming factor

• RNA is responsible for heredity

What did Avery, McLeod, and McCarty use to destroy proteins in their experiment?

• Acid

• Radiation

• Enzymes

• Heat

What type of virus did Hershey and Chase use in their experiment?

• Influenza virus

• Bacteriophage

• Retrovirus

• Adenovirus

What did Hershey and Chase label with radioactive sulfur?

• DNA

• Proteins

• Lipids

• Carbohydrates

What was the key finding of Hershey and Chase's experiment?

• Proteins are the genetic material

• RNA is the main component of viruses

• DNA is injected into the host cell

• Viruses do not contain genetic material

What did the presence of radioactive phosphorus inside the bacteria indicate in Hershey and Chase's experiment?

• Proteins entered the bacteria

• DNA entered the bacteria

• The bacteria were destroyed

• The virus remained outside