Molecular Biology: Nucleosomes & Hershey-Chase Experiment

What component of a nucleosome wraps around the core of histone proteins?

What specific element was used to label the DNA in the Hershey and Chase experiment?

Which of the following statements about histone proteins is correct?

What was the primary conclusion of the Hershey and Chase experiment?

What happens to the tails of adjacent histone octamers during chromosomal condensation?

Nucleosome Structure

Hershey-Chase Experiment

Viral Genetic Material

32P Radioactive Label

35S Radioactive Label

Nucleosomes

Nucleosomes are composed of DNA wrapped around a core of eight histone proteins.
These histone proteins have positively charged amino acids that interact with the negatively charged DNA.
A linker DNA joins the core histone proteins.
Histone proteins have tails that extend outward from the nucleosome.
During chromosome condensation, tails from adjacent nucleosomes interact.

The Hershey-Chase Experiment

In the mid-20th century, scientists debated whether protein or DNA was the genetic material.
Some viruses have a DNA core and a protein coat.
In 1952, Hershey and Chase conducted experiments to prove DNA is the genetic material.
T2 bacteriophages were grown in radioactive sulfur (35S) or phosphorus (32P) to label proteins or DNA components.
Viruses with radioactive sulfur (35S) labeled proteins.
Viruses with radioactive phosphorus (32P) labeled DNA.
Bacteriophages infected bacteria (E. coli).
Centrifugation separated the bacteria from the virus remnants.
Bacteria infected with 32P-labeled viruses were radioactive, while bacteria infected with 35S-labeled viruses were not.
This proved that DNA, not protein, was the hereditary material.

This quiz covers key concepts in molecular biology, focusing on nucleosomes and the Hershey-Chase experiment. Explore the structure of nucleosomes and the pivotal experiments that demonstrated DNA as the genetic material. Test your knowledge on these fundamental topics in genetics and molecular biology.