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Frederick Griffith

proved heredity occurs at the molecular level and bacterial transformation

Bacterial Transformation

uptake and expression of foreign DNA

Oswald Avery

first to prove that DNA NOT protiens carries information

Hershey and Chase

second to prove indefinitely that DNA was the genetic material

Erwin Chargaff

Found that the % of Adenine almost = the % of Thymine and that the % of Cytosine almost = the % of Guanine

Rosalind Franklin

proved that DNA was a double helix

Watson and Crick

proved DNA structure, Purines to Pyrimidine, Adenine and Thymine have 2 H bonds & cytosine and guanine had 3 H bonds

DNA Structure

composed of two separate single strands of nucleotides held together by H bonding between nitrogenous bases.

The phosphate of a strand is its ___' and the sugar end is its ___' end.

3' and 5'

DNA Replication

production of 2 exact copies of ds DNA from 1 original ds DNA

"Semi-Conservative"

each of the 2 new replicate "daughter strands" contains Y2 of the original nucleotides and Y2 new nucleotides.

Origin Site

Is the site where replication can begin and progress in both directions.

Step 1 to DS DNA replication

Helicases attatch to the DS DNA origin sites and can move in either direction breaking H bonds

Step 2 to DS DNA replication

Single Stranded Binding Protiens (SSB's) follow the helicase and keep the H bonds from bonding back up.

Step 3 of DS DNA replication

Primase adds small segments of single stranded RNA to act as a "primer" and get the additional nucleotides started.

Step 4 of DS DNA replication

The leading strand is where the enzyme DNA polymerase links to the primer and adds new nucleotides in the direction of replication.

Step 5 of DS DNA replication

The lagging strand is the strand in which dna polymerase must work away from the actual direction of replication, and DNA ligase links okazaki fragments so that there is a continuous double stranded DNA.

The enzyme that makes a mistake every 1 in 10 billion

DNA Polymerase

Excision

cut out a mistake and replace it with new nucleotides by DNA polymerase.

Building Blocks for Nucleic acids

Nucleotides

Gene

sequence of DNA nucleotides that codes for the building of a specific protein

RNA

single stranded, Ribos sugar instead of Deoxyribos, no Thymine but Uracil instead.

Types of RNA

mRNA, tRNA, rRNA

mRNA

messenger RNA that carries info from DNA to ribosomes

tRNA

transfer RNA that brings amino acids to ribosomes

rRNA

ribesomal RNA that is not for coding but part of ribosome structure with protein.

DNA to RNA to Protein inbetween steps

Transcription then Translation

Translation

converting info of mRNA into an amino acid sequence (protein)

Genetic Code

based on mRNA nucleotides, Triplet code-3 bases required to specify one of 20 possible amino acids

Ribesomes Structure

Large Subunit, Small subunit

tRNA structure

single stranded RNA with numerous loops

Mutations

a change in DNA

How mutations occur

Replication

Levels of mutation

Nucleotide, Gene, Chromosome

Point Mutations

involving a single base up to 3 bases (codon) [will affect 1 amino acid]

"Silent Substitution"

change a base but still code for the same amino acid

"Missense Substitution"

Base change causes a codon to code for a different amino acid

"Nonsense"

substitution changes a codon to a stop codon [can be very harmful]

Frameshifts

base is either inserted or deleted from a gene. Every codon downstream gets altered. (very damaging)

Mutagen

a chemical that causes mutation

Carcinogen

mutagen that causes cancer

Introns

sequences in genes that don't code for anything

Exons

sequences in genes that code for amino acids

Satallite DNA

outside of genes codes for nothing

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