Genetics Scientists & Enzymes

Friedrich Miescher

discovered DNA in 1869; nuclein -> nuclei -> pus cells

Phoebus Levene

An organic chemist in the early 1900s that had an incorrect tetranucleotide hypothesis of DNA; DNA made of nucleotides

Frederick Griffith

Discovered transformation during an experiment that involved injecting mice with smooth S cells, rough R cells, heat-killed S cells, and heat-killed S cells with living R cells.

Hammerling

worked with unicellular algae, proved genetic info was in nucleus (so it couldn't be proteins)

Avery, MacLeod, McCarty

Proved that DNA is the hereditary material

Chargaff

The individual responsible for discovering the base pairing rules for DNA.

Hershey and Chase

concluded that the genetic material of the bacteriophage was DNA, not protein.

Linus Pauling

Discovered the alpha helix structure of proteins, thought DNA was triple stranded

Rosalind Franklin

Woman who generated x-ray images of DNA, she povided Watson and Crick with key data about DNA

James Watson and Francis Crick

1953. Built first accepted DNA model explaining specific structure and properties of DNA.

Meselston and Stahl

semi-conservative replication

half heavy N15, half light N14

Helicase

An enzyme that untwists the double helix of DNA at the replication forks.

single strand binding proteins

bind to the unpaired DNA strands, keeping them from re-pairing

Topoisomerase II

works upstream from the replication fork to relieve the stress on the double helix that results from its unwinding at the replication fork

Primase

An enzyme that joins RNA nucleotides to make the primer using the parental DNA strand as a template.

DNA polymerase III

In charge of synthesizing nucleotides onto the leading end in the classic 5' to 3' direction.

DNA Polymerase I

Removes RNA nucleotides of primer from 5' end and replaces them with DNA nucleotides

DNA ligase

an enzyme that eventually joins the sugar-phosphate backbones of the Okazaki fragments

exonuclease

an enzyme that removes successive nucleotides from the end of a polynucleotide molecule

DNA Polymerase II

enzyme that proofreads the daughter strand of replicated DNA and corrects any base pairing errors

RNA polymerase

Enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription

Poly A polymerase

adds poly A tail at the end of RNA

aminoacyl-tRNA synthetase

An enzyme that joins each amino acid to the appropriate tRNA.

peptidyl transferase

An enzyme in the ribosome responsible for peptide bond formation during translation.

Beadle and Tatum

Showed that genes code for enzymes

Frederick Sanger

pioneer in determining the amino acid sequence of proteins through insulin

Francois Jacob and Jacques Monod

discovered the role of mRNA in protein synthesis

Jacob, Brenner, Meselson

Confirmed messenger RNA

Crick and Brenner

concluded that the genetic code is read as a triplet of nucleotides continuously, no punctuation

RNA polymerase

Enzyme similar to DNA polymerase that binds to DNA and separates the DNA strands during transcription

reverse transcriptase

An enzyme encoded by some certain viruses (retroviruses) that uses RNA as a template for DNA synthesis.