Translation

cellular factors that we need to turn out mrnas into proteins

amino acids, mRNA, ribosomes, transfer RNAs, initiation factors, elonhgation factors, termination factors

Amino acids

2o major amino acids needed

arginine abreviation (1 letter)

R

what direction is peptide synthesized?

N to C

mRNA

what carries the genetic infor over from the nucelus to ribosomes, it has the codons that specify what amino acids need to make up the chain

start codon

AUG

Stop codons

UAG, UAA, UGA

fearures of genetic code

non overlapping (one codon corresponds to one amino acid), commaless (triplet codons read in continutaion- no gaps), degenerate (one amino acid can be specified by more than one triplet), unambiguous (a single tripelt specifics ONE amino acid)

sites of subunit

a (acceptor), p(peptide), e (exit)

How many loops does tRNA have

4

what are the tRNA loops

T loop, D loop, variable arm, and anticodon loop

T loop

found near 3’ end, interacts with ribosomes to help positioning

d loop

foudn near 5’ end, recognized by aminoacyl t RNA snythases for correct charging of tRNA with amino acid

variable arm

length varies between trnas, helps in recognition and stability

anticodon loop

has an inosine in 5’ of trna for wobble position

tRNA wobbling

the insoinse can bind to U ,C, and A so depdening on the sequence a single tRNA can bind to multiple codons (reducing overall amoutn of codons needed)

prokaryotic ribosome

30S + 50S

Eukaryotic ribosome

40s and 60s

inittation mechanism in proks

shine dalgarno sequence

Shine dalgarno sequence

3-9 purines that are slightly upstream of initiation codon

initiation mechanism in euks

5’ cap and kozac sequence

initaitor tRNA in proks

fMet

initiatior trna in euks

met

polyribosome

group of ribosomes that translate the same mRNA at the same time

signal recognition peptide

ribonucleoprotein complex thats plays the role in co translational targeting of proteins to ER (makes sure that the proteins get dlivered to their corect spot depending on what they’re needed for)

protein folding

the way proteins are folded after translation determines their domain strcutrue and function

where is shine dalgarno (AGGAGG) sequence located

upstream of start

where is kozak sequence (ACCAUGG)

surrounds start codon (AUG)

Coding sequnce/ ORF (open reading frame)

the sequence between start and spot codons

what are post translational mods

modification of the amino acids of protins by adding on extra functional groups, to help with stability, activity, localization and interactions

reversible ptms

ading biomolecules like polypetides, nucleotides, carbs, lipids, and adding on chemical functional groups

irreversible ptms

any kind of cleave activation, amino acid mods like deamidation (removing amine group) or eliminlyation (removing functional groups and converting chemicla nature)

common types of ptms

acetylation, mthylation, oxidation, nitrosylation, glyocsilation, ubiqutination

Acetlyation

acetyltransferases use acetyl coA to add in an acetyl group (COCh3) to amino group of usually lysine

ubiquitylation

adding ubquitin on, signals the protein for degredation

phosphorylation

phosphate group is attached to certain amino acid side chains like serine, theronine, and tyrosine (reversible)

post translational folding of proteins

primary, secondary, tertiary, quaternary

Primary protein structure

the sequence of amino acids in a polypeptide, stabalized by peptide bonds

secondary protein structure

formation of alpha helices and beta pleated sheets in a poly peptide

how are secondary folded proteins stabalized

h bonding between groups along peptide bonded backbone

tertiary protein structure

overall 3 dimensional shape of a polypeptide

how are tertiary and quaternary folded proteins stabilized

interactions between r groups

quaternary folded proteins

the shape made by combinations of polypeptides

phosphorylation is mediated by what kinds of molecules

kinases (receptor tyrosine kinases)