DNA Replication

Leading Strand

Synthesized continuously because DNA polymerase is adding nucleotides to the 3' end as helicase continues to unwind

Lagging Strand

Synthesized in small fragments because DNA polymerase is adding nucleotides to the 3' end

DNA Polymerase

Synthesizes new DNA strand by adding new DNA nucleotides

Primase

Adds RNA primer for DNA polymerase to use as a starting point to build daughter strand

Ligase

Glues together Okazaki fragments on the lagging strand

Single Strand Binding Proteins

Essential cellular helpers that clamp onto unwound DNA strands, keeping them separate, stable, and accessible

Helicase

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

Topoisomerase

Enzyme that functions in DNA replication, helping to relieve strain and prevent tangling in the double helix ahead of the replication fork.

Antiparallel

The opposite arrangement of the sugar-phosphate backbones in a DNA double helix. Leads to formation of a leading strand and a lagging strand in DNA replication.

Griffith

discovered bacterial transformation

DNA replication

The process in which DNA makes a duplicate copy of itself.

Base pairing rules

Thymine always pairs with Adenine, and Cytosine always pairs with Guanine

Avery McCarty and MacLeod

Transformation cannot occur unless DNA is present - DNA is genetic material

Hersey and Chase

DNA, not protein, is genetic material

Erwin Chargaff

discovered that A=T and G=C

Watson, Crick, Franklin, & Wilkins

Discovered double helix

Meselson and Stahl

Proved semi-conservative strand replication of DNA with nitrogen

semiconservative replication

each new DNA molecule consists of one new strand and one old strand

DNA Back Bone

Made from Phosphate and Deoxiribose

Nucleotide

monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

anti-parallel strands

2 strands of DNA run in opposite directions

Purines

Adenine and Guanine

Pyrimidines

Cytosine, Thymine, Uracil

Okazaki fragments

the DNA fragments that are synthesized in short stretches on the lagging strand

replication fork

A Y-shaped region on a replicating DNA molecule where new strands are growing.

replication bubble

gap in the DNA formed as the replication fork expands

RNA primer

short segment of RNA used to initiate synthesis of a new strand of DNA during replication