proved heredity occurs at the molecular level and bacterial transformation
uptake and expression of foreign DNA
first to prove that DNA NOT protiens carries information
Hershey and Chase
second to prove indefinitely that DNA was the genetic material
Found that the % of Adenine almost = the % of Thymine and that the % of Cytosine almost = the % of Guanine
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
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'
production of 2 exact copies of ds DNA from 1 original ds DNA
each of the 2 new replicate "daughter strands" contains Y2 of the original nucleotides and Y2 new nucleotides.
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
cut out a mistake and replace it with new nucleotides by DNA polymerase.
Building Blocks for Nucleic acids
sequence of DNA nucleotides that codes for the building of a specific protein
single stranded, Ribos sugar instead of Deoxyribos, no Thymine but Uracil instead.
Types of RNA
mRNA, tRNA, rRNA
messenger RNA that carries info from DNA to ribosomes
transfer RNA that brings amino acids to ribosomes
ribesomal RNA that is not for coding but part of ribosome structure with protein.
DNA to RNA to Protein inbetween steps
Transcription then Translation
converting info of mRNA into an amino acid sequence (protein)
based on mRNA nucleotides, Triplet code-3 bases required to specify one of 20 possible amino acids
Large Subunit, Small subunit
single stranded RNA with numerous loops
a change in DNA
How mutations occur
Levels of mutation
Nucleotide, Gene, Chromosome
involving a single base up to 3 bases (codon) [will affect 1 amino acid]
change a base but still code for the same amino acid
Base change causes a codon to code for a different amino acid
substitution changes a codon to a stop codon [can be very harmful]
base is either inserted or deleted from a gene. Every codon downstream gets altered. (very damaging)
a chemical that causes mutation
mutagen that causes cancer
sequences in genes that don't code for anything
sequences in genes that code for amino acids
outside of genes codes for nothing