DNA

Claire 11/29/10

AZT- has a shape similar to T nucleotide in DNA and binds to the viral enzyme instead of T. Therefor, it blocks spread of HIV virus

Griffith- found "Transforming Factor"-killed harmful bacteria with heat, mixed with living cells of nonharmful bacteria, nonharmful bacteria became harmful. "Transforming Factor" was inherited by originally unharmful bacteria(which changed)

Hershey and Chase- DNA of a virus that is injected into host cells reproduces new viruses.

Franklin (& Wilkins)- Found helical shape (spins around itself) of DNA with x-ray crystallography

Watson and Crick- model of DNA, base pairing(what bonds with what), double helix structure

Earn Nobel Prize with Wilkins in 1962--Franklin died and was not included because they didn't want to give to this award to a female

Structure

Double Helix

nucleotide=1 sugar, 1 phosphate, 1 base

nucleotide=monomer

DNA=polymer

nucletides change to DNA through d

ehydration synthesis

Nucleic acid-"polynucleotide"

4 Nucleotides(bases): A=Adenine C=Cytosine T=Thymine G=Guanine

G bonds with C

A bonds with T

form hydrogen bonds with each other

DNA has three rings across, A and G have 2 rings and C and T have one. A and G can't bond because there would then be 4 rings across

T and C=pyrimidines(single ring)

A and G=purines(double ring)

N bases protrude from sugar

sugar-phosphate backbone

sugar=5 carbon ring=deoxyribose(missing oxygen atom)

1 nucleotide= nitrogen base, sugar, phosphate

nucleotides joined by covalent bonds between sugar and phosphate

Chargaff- in DNA, amount of A=amount of T, amount of G=amount of C (proves base pairing)

Sequence of bases in DNA determines kind of gene on chromosome

DNA Replication

occurs in nuclues

Parent DNA untwists, strands separate

N bases attach to complementary base (A to T, G to C)

2 Daughter DNA molecules-rewinds and formed

Polymerases- enzymes that make covalent bonds between nucleotides of new DNA strand

very unlikely to be paired incorrectly

DNA Polymerase and other protiens can repair damaged DNA

DNA harmed by: UV rays, X-rays, viruses

Replication begins at origins(beginning)

goes in both directions-forming a bubble

bubbles can merge

genetic instructions are copied for the next generation

Beadle and Tatum- one gene produces one speacific enzyme/protien/polypeptide

Sections on DNA code for certain amino acids

20 amino acids total

triplet codes-codons(necessary)

G,T,C,A(4) * G,T,C,A (4)= 16 (not enough

G,T,C,A(4) * G,T,C,A (4)*G,T,C,A(4)=64 different triplets(more than enough)

Next Scribe:Bridget