Transformation
gaining new dna from somthing else can change genome
the transforming principle is
dna
griffith discovered
transformation with his mice and smooth and rough bacteria
avery discovered
dna is the transforming principle
hershey and chase discovered
the dna is herdiitary materical by labeling it radioactively in bacteriophages
rosalind franklin discovered
dna is coild but she thought single strand
watson and crick discovered
dna is double stranded along with much of its structure
chargaffs rule
a+t g+c
dna replication is semiconservative
after replication in the 2 daghter strands of dna 1 strand is new and 1 strand is old in each one
meselson and stahl discovered
dna is semiconservative with tracking bacteria replication in different isotopes of nitrogen and then seeing the bands in density centrifuge
dna replication happens semidiscontinously
bc 1 strand is being replication constinsouly and the other is being synthesized in fragments
leading strand
strand being synthesized continously
lagging strand/okazaki fragments
the fragments being syntheszed in pieces
dna is made
5’ to 3’
dna is copied
3’ to 5’
5’ end is
phosphate terminus
3’ end is
hydroxyl terminus
relication fork
dna being copied in 1 direction
replication bubble
dna being copied in both directions will eventually burst seperating the fragments
origin of replication
where dna replication starts
helicase
unwinds, uncoils, unzips DNA
single strand binding proteins
bind to each unzipped DNA strand and keeps them apart until replication is complete
primase
since DNA polymease cant start replication primase comes in and srtart it by addinf a 10 ribonucleotide RNA primer at teh beging of replication, adds it to every place a new okazaki strand is started
DNA polymerase lll
now starts by adding deoxynucleotides at the 3’ end of the primer extending DNA from 5’ to 3’
DNA polymerase l
cuts of RNA primer and replaces it with deoxynucleotides DNA
DNA ligase
okazaki fragment also has RNA primer after it is cut out and replaced by deoxynucleotides by DNA polymerase l the fragements are glued together
topoisomerase
relaxes supercoiled DNA before replication fork
as DNA polymerase adds base it also
proof reads, it adds about 50 bases per second in mammals and 500 bases per second in bacteria, and it usually only makes 1 mistake in 10.000
why do we need to make proteins if we eat them
we only eat some of the amino acids and proteins that we need so the ones we do eat are broken down to raw material or amino acids and used for whatever it is they are needed for or they are used to form new proteins that we need bu cant consume
gene expression/ protein synthesis
express or decode your genes to make proteins made up of 2 steps transcription and translation
transcription
takes place in the nucleus, dna unwinds/uncoils and then unzips, transcribing or copying dna begins at a sequence of bases on the dna called the promoter, then rna polymerase binds to the promoter sequence on one dna strand (template) and copies the bases by adding complementary ribnucleotides to make mRNA, a is copied as u bc rna doesnt have t, mrna can exit the nuclues and survive
sense strand
the bit of dna that is copied and later coded
spliceosomes
help in mRNA splicing, settle on either end of the intron and then slowly close together until a loop is formed that is then ct off leaving only exons on the mRNA
post transcription modification
rna intron splicing, poly a tail is added to the 3’ end and g cap is added to the 5’ end
intron
part of mRNA that is never expressed, can’t go into the cytoplasm so must be removed from mRNA
mRNA is the same length
as the DNA it was copied from but after post transcription modification it will be shorter then the DNA it was copied from
mature mRNA is _____________ than DNA
shorter
mature mRNA is
what is left after post trnacription modification this mRNA is ready to go out into the cytoplasm and will survive
exon
part of mRNA that is expressed and not cut out of the mRNA during post transciption modification, can survive outside of the nucleus
codon
the 3 base pairs in mRNA that will code for 1 amino acid
anticodon
the amino acid coded from the complimentary pairs from mRNA, only ue is to bond to codon
start codon
AUG
stop codon
UAA, UAG, UGA
translation
the message on the mRNA is read/decoded as a triplet of bases calleda codon, the decoding/interpreting is done by tRNA which reads the codon b using the genetic code, the gentic code is universal for all living things and is the correlation of codon to the amino acid, the tRNA connects to the codon on mRNA with its anticodon(triplet of bases complimentary to the codon) that carries the coressponding amino acid at its other end, as the codons are decoded by tRNA amino acids are joined together
post translation modification
protein folding into correct tertiary structure
wobble hypothesis
even if the 3rd base changes in a codon it will most likely code for the same amino acids, this is bc the 3rd base is most likely to mutate and therefore nature made it so these mutations should go unnoticed, the 3rd base and change and the protein created will be the same
transposons
jumping genes, spontaeous cause unknown, move from one location in dna to another, causes mutations, not noticed if the change stays in the intron
missense mutation
substitution
gene regulation
genes are switched on and expressed when the cell needs the proteins and switched off whe the proteins arent needed
exons
coding regions of gene on DNA that ar expressed into proteins
introns
noncoding regions between exons intervening, not expressed
lac operon
genes that control the metabolim of lactose
operon
group of genes that work together to do something
functional genes in lac operon
r p o, they control the function of the other genes by turning the on and off
structural genes in lac operon
z y a, genes that are expressed and code for the proteins and enzymes that metabolize lactose
r
regulator gene that produces repessor protein
p
promotor, where RNA polymerase bonds
o
operator, where the repressor protein binds
allo-lactose
inducer, binds to repressor and pulls it off of the operator
lac operon explained
sequence is rpozya, the repressor protein taht is formed by the regulator gene loved the operator gene and the moment it is made and released it moves and binds to the operator, this leads to the RNA polymerase taht is bonded to the promoter gene behind the operator gene to get stuck and not be able to continue transcription of zya and therefore there are no enzymes produced, once lactose is ingested allo-lactose an inducer comes in and takes the repressor protein off of the operator, this allows RNA polymerase to continue transcription which in turn creates teh proteins and allows lactose to be metabloized
e-coli
where lac operon is, not pathogenic so not bad, good in small amounts
when is the lac operon off
when there is no lactose and the repressor protein is free to stay binded to the operator
when is teh lac operon on
when there is lactose and the allo-lactose takes the repressor protein off of teh operator allowing transcirption
trp operon
synthesizes tryptophan
trp operon explained
the trp operon creates typtophan so when things like turkey or milk with tryptophan in it are ingested and tehre is tryptophan there is not need for trp operon to synthesize more so this is when the trp operon is off, when there is no moer tryptophan in teh system the trp operon turns on to synthezie more
when is the trp operon off
when there is tryptophan
when is the trp operon on
when there is no tryptophan
cleaving
isoltaing the donor gene from the rest of the DNA sequence
restriction enzymes
chemical scissors that recognize specific base sequences of DNA to cut out and around, ex. EcoRI enzyme for E coli cuts GAATTC
vector
vechile that carries the gene
plasmid
circular piece of self-replicating DNA found in bacteria that carries several genes including antibiotic resistance genes which serve as a genetic marker
recombinant gene
the spliced donor gene in a bacteria’s plasmid
transformation
bacteria that contains recombinant DNA
how insulin is made
first teh insulin gene is isolate and cleaved by the restriction enzyme EcoRI , after this the DNA is placed in a plasmid that had part of its DNA seqeunce removed to make room for the human DNA, after this the plasmid is placed back into the bacteria that then reprodcues and allows its DNA to replicate like normal meaning that it is also replicating the transformed plasmid or recombinant DNA creating insulin
cloning
asexual reproduction of cells to produce identical cells
human genome project
map the location of all the genes on the human chromosomes
polymerase chain reaction PCR
make multiple copies of DNA using enzymes DNA polymerase and deoxynucleotides
electrophoresis
seperation of macromolecules using electric current, used to compare DNA from different individuals/sources and to determine molecular mass of DNA, RNA, proteins
DNA fingerprinting
DNA from each individual is unique and gives a unique pattern like our fingerprints when the DNA is cut with restriction enzymes and seperated by a process called electrophoresis
inbreeding
2 lose sibling organisms with same traits
selective breeding
crossing 2 organisms with different traits to get desired traits from both organisms in the offspring
silencer
regulator DNA elements that reduce transcription from their target promoters
homeotic gene
regulate anatomical strucutres in various organisms
oncogene
a gene in which certia circumstances can turn into a tumorous gene
carcinogen
substance capacble of causing cancer
enhancer
activates transcription levels to higher levels then if it wasnt there
protooncogene
genes that help cells grow
lytic viruses
phages that shoot DNA into host bacteria and take over bacteria and reproduce bacteria in the cell, when the baby phages are made they burst ope the bacteria and are released host cell dies
lysogenic
these phages do not kill their bacterial host they shoot the DNA in and incorporate their DNA in the bacterial DNA, as the baterial AND replicates the viral DNA is introduced into the cell, transduction is used
transduction
process in which forgein DNA is introdued into a cell using a virus
enzyme reverse transcriptase
RNA→DNA before it can be turned into a protein
transformation
introducing naked DNA into a cell to change/transform traits
recombinant DNA
dna from 2 different organisms
conjunction
exchange of DNA in bacteria through pili during mating
cDNA
complemntary DNA, DNA molecule made in vitro using mrNA as template and the enzyme reverse transcriptase, corresponds to gene but lacks the introns present in the DNA of the genome
radioactive probes
labeled nucleic acid molecules used to find specific gene/other nucleotide sequenes within the mass of DNA
RFLP
restriciton fragement length polymorphisms, diffrences in homologs DNA seqences that are reflected in different lengths of restriction fragments roduced when DNA is cut up with restriction enzymes
teolmeres
repetitive DNA at chromsome ends also have protetive function, significant loss of telomeric DNA quickly leads to cell death, abnormal length may help immortal cancer cells evade normal cell agging
chromosome puff
chromosome regions that puff out to copy DNA to mRNA during transcription
gene therapy
alterations of individual gene in people with disorders to replace/supplement defetive gene with normal gene/allele