Bio exam2

Metabolic disorders

an issue with food to energy caused by absence of enzyme fuctio

Inborn error

indicidual can not generate an entire enzyme causing metabolic disorder

Beadle and tatum

exposed cells to x rays until they mutated, see what cells couldnt grow without certain nutrients, added different chemical intermidiates make that nutrient to see what enzyme is affected

claim 1 gene= 1 enzyme

Griffith

used pnuemonia, rough (no cell wall) and heat treated smooth cells, they killed mice together showing transformation

Avery, mcarty and macleod

did same thing as griffith but added things to degrade either dna rna or protiens which showed dna causes transformation

hershey and chase

further show dna causes transformation, made everything radioactive could see that protien remains in supernatant while dna causes cell to become radiactive

Nucleotide

has sugar, phosphate and nitroginous base (T, A, C or G)

atoms in sugar are numbered with prime

Nitrogenous base is connected at 1 prime carbon on sugar and phosphate is connected to 5’ on sugar

Chargaff

showed each specias has a different amount of the dna bases

but ratios A:T =1 and G:C=1

Rosalind franklin

Discovered double helix, A and T always bind across G and C always bind across

Watson and crick

made three models for DNA replications

conservative model, orignal makes an entirely new strain

semi conservative where it makes top strand is original bottom is new THIS IS THE RIGHT ONE

dispersive model where it is a complete mix

Transcription

RNA copy of the dna in nucleotides

Translation

sequence of nucleotides into amino acids

DNA

sugar of deoxyribose and bases GC AT

RNA

a transient messenger intermediate molecule, so it needs to be able to be degraded

the sugar is ribose with an extra hydroxyl acts as a nucleophile and leaves

uracil instead of thymine

Reverse transcription

rna is copied into a dna molecule by viruses like hiv which goes into cells chromosomes so they make more copies of the virus

RNA polmerase

For transcription

binds directly to promoter but in eukaryotes it needs transcription factors (helpful proteins)

knows what direction to transcribe because the promoter orients it

DNA replication

1. Helicase unzips dna/template strand, topoisomerase breaks a sugar back bone releasing the twisting/ribbing when the helicase separates them 

2. DNA primase allows polymerase to bind by adding a rna primer

3. DNA polymerase III follows the helicase, reading from 5’ (start) to 3’ (end)

4. rna primers are then removed by dna polymerase I and fills the gaps with dna

5. ligase attaches the gaps filled with dna and the daughter strand

dna replication, okazaki fragments

1. the two unzipped strands are antiparallel so the other strand is 3’ to 5’making a replication bubble

2. dna polymerase III can only read 5’ to 3’ so it needs to do this part in okazaki fragments

3. multiple primase lay down rna primers in the opposite direction, the multiple primers allow the polymerase to do more as the helicase moves (goes opposite of direction of replocation

the end replication problem

With lagging strand synthesis it stops short of the end because helicase will be right at the end

telomerase goes at the very end makes and rna copy that is stitched into previous dna which is replaced by dna polymerase I and ligase

it is only an important amount of dna to loose if fast replicating cell like cancer or skin or hair

Transcription

DNA to mRNA

rna polymerase translates it by matching amino acids U to A A to T and G to C

occurs in nucleus

Translation

mrna helps the tRNA ribosome (30s on bottom of rna 50s on top) bind to rna and find the starter codon AUG at the p site they read 5’ to 3’

Anticodons hydrogen bond to the complimentary bases

Aminoacyl tRNA synthesase attach the amino acids, they have a specific amino acid on them but can bind to more than one set of codons

the new tRNA binds to the A site and the amino acids at p site on initial tRNA moves ontop of new tRNA and the initial tRNA moves to exit/ e site and continues

Regulation of gene expression

 It goes DNA,  regulatory gene, promoter then operator then gene.

inducers that bind to the operator to make the op erator change shape and unbind allowing gene to unexpress is called an inducible operon but if a repressor protein binds to a operator and the operator binds then it is a repressable operon. They are dimers that fit together as a puzzle.

One promoter that controls multiple genes is called operons but they all have their own start codons and stop codon

Introns and exons

in mRNA

introns are sequences that are removed during rna splicing

exons are the genetic code left they contain the codons

Types of protein structures

Primary-chain of amino acids in each cell

Secondary-specific chain of amino acids alpha helix or beta sheets can be a combo, not present in every protien

Tertiary-three dimensional can contain secondary or other confirmations, in every protein. Known as polypeptide chains

Quaternary- a mix of tertiary structures/different polypeptide chains, not in every protein

protein folding

most proteins fold to what is the most thermodynamically stable, but if the active version is not the most thermodynamically stable there will be a chaperone protein to help it stay

Amino acid structure

side chain is different for each amino acid

some side chains are polar and thus hydrophilic, existing on outside of protein. Opposite for non polar side chains. Electrophilic side chains tend to be acids or bases that are hydrophillic

How are amino acids connected

dehydration synthesis, alcohol on carbonyl group attaches to another hydrogen on amine of another amino acid hydrogens creating water and C-N bond

small mutation

insertion or deletion or change of a single nucleotide

big mutation

change in chromosome structure

when is an allele considered a mutation

if it occurs in <1% of population and is harmful

what is a error that occurs in ≥1% of the population

polymorphism

what type of mutation is sickle cell anemia?

single point small mutation

Frame shift mutation

Addition or subtraction of nucleotide that changes the order of codon and messes up entire protein

splicing mutation

introns are not removed

Promoter mutation

prevents transcription because rna polymerase can not bind

Tautomeric shift

a state of an amino acid changes which caues it to be mismatched in nucleotide pairing

Induced mutations

physical damages(radiation)

or

chemical damages

why is dna polymerase mutations not much of an issue

happens 2/1000 nucelotides gives wrong pairing but has built in check system that uses detects issues in hydrogen pairing