DNA Scientists + Structure

Transforming Principle

The substance responsible for transforming non-pathogenic bacteria into pathogenic forms, identified by Griffith.

S-strain Bacteria

The strain of bacteria that is disease-causing in Griffith's experiment.

R-strain Bacteria

The harmless strain of bacteria used in Griffith's experiments.

Transformation

The process by which genetic material is transferred from one bacterium to another, changing the latter's characteristics.

Avery's Experiment

The series of tests conducted by Avery to identify DNA as the transforming principle.

Hershey-Chase Experiment

An experiment that demonstrated that DNA is the genetic material of viruses, using radioactive isotopes.

Chargaff's Rules

The observation that the amounts of adenine equal thymine (A=T) and guanine equal cytosine (G=C) in DNA.

X-ray Diffraction

A technique used by Rosalind Franklin to study the structure of DNA, revealing its helical nature.

Double Helix

The structure of DNA, consisting of two intertwined strands that resembles a twisted ladder.

Base Pairing

The specific hydrogen bonding between adenine and thymine, and guanine and cytosine in DNA.

Nucleotides

The building blocks of DNA, composed of a sugar, a phosphate group, and a nitrogenous base.

Antiparallel Strands

The orientation of the two strands of DNA which run in opposite directions.

Hydrogen Bonds

Weak bonds that form between nitrogenous bases in DNA, stabilizing the double helix structure.