Molecular Genetics

Frederick Miescher

First to discover DNA, extracted nuclein from white blood cells in 1869.

Nuclein

Name given by Miescher to DNA, later renamed nucleic acid due to its acidic properties.

Transforming Principle

Concept from Griffith's experiment that a non-virulent R strain of bacteria could be transformed into a virulent S strain by something from the heat-killed S strain.

Avery, MacLeod, and McCarty's experiment (1944)

Identified DNA as the transforming principle using killed S and live R strain bacteria.

Hershey and Chase experiment (1952)

Demonstrated DNA is the hereditary molecule by using radioactive markers to track DNA and protein in bacteriophages.

Chargaff's Rules

Found that the amount of adenine equals thymine and the amount of cytosine equals guanine in DNA.

X-ray Crystallography

Technique used by Franklin to reveal the helical structure of DNA.

Watson and Crick's Double Helix Model

Describes DNA structure as a double helix with complementary base pairing.

Semiconservative Replication

Means that each new DNA molecule contains one original strand and one new strand.

Telomeres

Repeating non-coding DNA sequences that protect the ends of eukaryotic chromosomes.

Senescence

A state where a cell permanently stops dividing after reaching the Hayflick limit.

Cancer Cells and Telomerase

Cancer cells produce high levels of telomerase, preventing telomere shortening and allowing them to divide uncontrollably.

Nucleosome

Unit of DNA wrapped around histone proteins, forming chromatin.

Chromatids

Two identical halves of a replicated chromosome.