mRna
messenger- rna for template for proteins
rRna
ribosomal- component of machine for synthesis of proteins
tRna
transfer- 1 strand, self complementary pairs, synthesis of protein transfer
transcription
gene expression
steps of transcription
- gene- promotor for DNA
- TF 2- find promotor, brings RNA pol. and initiative
- helicase- unwinds
- elongation
- terminator
transcription factors
-proteins that bind to promotors= TF2 and work with Pol II
-TF2 might go to specific gene and drive that specific trans.
-all same DNA, TF2 transcribes different genes for different things
promotor
specific sequence of DNA that codes for the start of transcription
Termination site
specific sequence of DNA that codes for the end of transcription
Post transcriptional modifications
-splicing- cutting out introns, SnRNP binds at the end of intron facilitating cutting
-5’ Cap- starts translation
-poly-a tail- 3’ end, long sequence of A for protection from DNAse and RNAse
Translation
protein synthesis (ribosomes)
genetic code
semi-redundant, 64 codons, 20 amino acids
aminoacyl-tRNa synthase
enzyme that takes amino acid and binds to tRNA and matches anti-codon to amino acid using atp
steps of translation
- Initiation- AUG, assemble tRNA, mRNA, small and large together, EIF brings tRNA then the large binds, the tRNA is in P pocket and the A is open
- Elongation- new tRNA can come in A pocket, EF-TU, ribosomes take amino acids off tRNA in P and connect them to the ones in A making a peptide, translocation- ribosomes slide down 3, tRNA is now in E
-Translocation- EF-TU, GTP (gives energy to slide down) - Termination- release facto binds to stop codon with causes everything to separate (UGA, UAA, UAG)
Couple transcription/translation
prokaryotic- both in cytoplasm, no intones, exons, translation starts before transcription ends
what is used in transcription/ translation
ribosomes, nucleus, cytoplasm, tRNA
NLS
nuclear localization signal (need to go to nucleus)
Signal sequence
makes polypeptides into rough ER
Post translational modification
proteolysis, glycosylation, phosphorylation
proteolysis
large portions into sections for function
Glycosylation
add sugars, important for plasma membrane
phosphorylation
add phosphate, activate/ deactivate proteins
