-eukaryotic chromosomes are composed only of protein and DNA

-some substance in the heat killed, deadly strain, changed the living but harmless strain into the deadly strain

-Transformation

-Later found that DNA was the substance

DNA Consistencies

(Chargaff's Rule)

-DNA of any given species contains equal amounts of adenine and thymine

-as well as equal amounts of guanine and cytosine

-Used microscope to study DNA molecule

-DNA is long and thin (uniform diameter of 2nm)

-DNA is helical

-DNA consists of repeating subunits

-combined Wilkin's and Franklin's information with their knowledge of how complex molecules bond together

-proposed a model for the structure of DNA

-DNA is in 2 strands

-phosphates of one bond to sugar of another

-2 strands are held together by hydrogen bonds

-A-T, G-C

-complementary base pairs

-explains Chargaff's Rule

-DNA helicases pull apart parental double helix

-DNA polymerases move along the strands, matching and connecting bases on the strand with complementary free nucleotides

-

-very rare

-when repair enzymes accidently cut out a correct  nucleotide instead of the incorrect one, it's called a point mutation

-when one or more nucleotide pairs are inserted into double helix, it's called insertion mutation

-when one or more nucleotide pairs are removed from double helix it's called deletion mutation

-when a piece of cut out of chromosome, turned around, and reinserted, it's called inversion

-when a chunk of DNA, often very large, is removed from chromosome and attached to another:translocation