Podcast
Questions and Answers
In 1952, which two scientists showed that DNA (not protein) was the genetic material of cells?
In 1952, which two scientists showed that DNA (not protein) was the genetic material of cells?
- Rosalind Franklin & Linus Pauling
- Gregor Mendel & Charles Darwin
- James Watson & Francis Crick
- Alfred Hershey & Martha Chase (correct)
What did Alfred Hershey and Martha Chase show in their experiment?
What did Alfred Hershey and Martha Chase show in their experiment?
DNA (not protein) was the genetic material of cells
How was evidence derived in the Hershey-Chase experiment?
How was evidence derived in the Hershey-Chase experiment?
Evidence was derived from studies that tracked viral infections of bacteria
____ consist of DNA (or RNA) enclosed by a protective coat of protein.
____ consist of DNA (or RNA) enclosed by a protective coat of protein.
Viruses consist of _____ (or _____) enclosed by a protective coat of protein.
Viruses consist of _____ (or _____) enclosed by a protective coat of protein.
What is a bacteriophage?
What is a bacteriophage?
In the Hershey-Chase experiment, T2 phage infected what bacteria cells?
In the Hershey-Chase experiment, T2 phage infected what bacteria cells?
Hershey-Chase designed an experiment where they were able to ______ the viral protein or DNA & then tracked which entered the E coli cell during infection.
Hershey-Chase designed an experiment where they were able to ______ the viral protein or DNA & then tracked which entered the E coli cell during infection.
Hershey-Chase designed an experiment where they were able to radiolabel the _____ or _____ & then tracked which entered the E coli cell during infection.
Hershey-Chase designed an experiment where they were able to radiolabel the _____ or _____ & then tracked which entered the E coli cell during infection.
What did radio labeling allow for in the Hershey-Chase experiment?
What did radio labeling allow for in the Hershey-Chase experiment?
What was the hypothesis of Hershey and Chase for their experiment?
What was the hypothesis of Hershey and Chase for their experiment?
How did the virus replicate in the Hershey-Chase experiment?
How did the virus replicate in the Hershey-Chase experiment?
What elements make up DNA?
What elements make up DNA?
What elements make up protein?
What elements make up protein?
During the Hershey-Chase experiment, they grew one batch of T2 phage in the presence of radioactive _____, marking the proteins, but not the DNA.
During the Hershey-Chase experiment, they grew one batch of T2 phage in the presence of radioactive _____, marking the proteins, but not the DNA.
During the Hershey-Chase experiment, they grew a second batch of T2 phage in the presence of radioactive _____, marking the DNA, but not the proteins.
During the Hershey-Chase experiment, they grew a second batch of T2 phage in the presence of radioactive _____, marking the DNA, but not the proteins.
During the Hershey-Chase experiment, why was the blended mixture put into a centrifuge?
During the Hershey-Chase experiment, why was the blended mixture put into a centrifuge?
What is a centrifuge?
What is a centrifuge?
Define supernatant.
Define supernatant.
In the Hershey-Chase experiment, was the viral coat found in the supernatant or the pellet?
In the Hershey-Chase experiment, was the viral coat found in the supernatant or the pellet?
In the Hershey-Chase experiment, was the bacteria found in the supernatant or the pellet?
In the Hershey-Chase experiment, was the bacteria found in the supernatant or the pellet?
Define pellet.
Define pellet.
After the centrifuge, what were Hershey & Chase looking for in the pellet & the supernatant of the separate treatments?
After the centrifuge, what were Hershey & Chase looking for in the pellet & the supernatant of the separate treatments?
What was the result of the Hershey-Chase experiment?
What was the result of the Hershey-Chase experiment?
Study Notes
Hershey-Chase Experiment Overview
- Conducted in 1952 by Alfred Hershey and Martha Chase.
- Determined that DNA, not protein, serves as the genetic material in cells.
Viruses
- Composed of DNA or RNA encased in a protein coat.
- Bacteriophages, or phages, specifically target bacterial cells.
Methodology
- T2 phage was used to infect E. coli bacteria.
- Experiment involved radiolabeling viral components (protein or DNA).
Radiolabeling Techniques
- Proteins were marked with radioactive sulfur, avoiding labeling DNA.
- DNA was marked with radioactive phosphorus, avoiding labeling proteins.
- Allowed tracking of the respective viral material during infection.
Infection Process
- Viruses inject their genetic material into the host.
- The host cells then replicate the viral DNA to produce new viruses.
Experiment Steps
- Infected cultures were subjected to blending to release any unabsorbed phage components.
- Mixtures were then centrifuged to separate bacteria (pellet) from free phages (supernatant).
Centrifugation
- Centrifuge spins mixtures, separating contents based on density.
- Supernatant is the liquid portion, while the pellet consists of denser bacterial cells.
Results Analysis
- Viral coats were found in the supernatant.
- Bacteria remained in the pellet.
- Radioactivity tests were conducted on both fractions to ascertain which viral components entered the bacteria.
Conclusions
- Results confirmed that DNA, labeled with phosphorus, entered the bacterial cells.
- Findings supported the hypothesis that DNA is the genetic material necessary for viral replication.
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Description
This quiz covers the discoveries made during the Hershey-Chase experiment, conducted by Alfred Hershey and Martha Chase in 1952. It reviews how this pivotal experiment demonstrated that DNA is the genetic material of cells, not proteins. Test your knowledge on the key concepts and findings associated with this significant scientific milestone.
