Sets 14 Flashcards
what is translation?
a process where the genetic code in mRNA directs synthesis of protein from AA
what is needed for translation ?
mRNA, tRNA & ribosomes
what is transfer RNA ?
its a short single strand RNA that is 74 to 94 nucleotide long that carries 1 AA
what are the 3 tRNA shapes?
Primary: the straight tRNA sequene
Secondary: has multiple hairpin loops
Tertiary: folded in three dimensional space
which ends do the AA attach on the tRNA
the 3’ end
what are modified bases on tRNA
they are bases on the anti codon that are chemical modified but can pair to AGCU on the mRNA
what is a wobble ?
the third position on the anticodon that can very ; where modified bases can be ex. “I” and recognize more than 1 codon
what are 3 things about the ribosome ?
its the site of protein synthesis
its composed of protein & RNA
has large and small subunit
what is SSU rRNA is in prokayotes ?
16S
what SSU rRNA is in eukaryotes ?
18S
what are the three phases in prokaryotic translation
- initiation
- Elongation
- Terminations
what are the 4 steps of prokaryotic Initiation phase ?
1.Shine Dalgarno sequence is recognized and the 16s Small unit binds
2. Start codon is recognized and initiates translation
3, tRNA which a chem-modified meth attaches to AUG (start codon)
4. Large subunit attaches and chem mod sight is at P site
what and how many sites does the large subunit contain ?
- EPA
exit
p ?
Arrival
what are elongation factors
they escort tRNA. to the A site
what 3 things happen at the elongation phase ?
Elongation factors
peptidyl transferase
the movement of tRNA from A-P -E
and polypetide chain grows
what makes the AA attach to other to make a poly peptide
the catalytic functions of the large subunit
what is peptidyl transferase ?
it catalyses the formation of a peptide bond between the C terminus of the mod MEth & N terminus of 2nd AA
what is the termination phase
when a stop codon is read; a release factor binds to the A site and the polypeptide is released and all the translation functions leave
what is the eukaryotic translation 3 initation step
- 5 Meth cap is recognized and 18S small subunit binds
- Start codon is found and regular meth tRNA binds
- Large subunit binds
what is the 2 biggest differences between euk & pro translation ?
the initiation of translation shine dalgarro vs 5 cap end
the met on the trna ; chem mod vs normal
what is a polyribosome ?
complex of many ribosomes translating the same mRNA strand in the 5 to 3 direc
can prokaryotes or eukaryotes transcrip and translate at the same
only prokaryotes can do it not euk bc translation happens in the cytoplasm and transcription happens in the nucleus
what are 3 types of post translational processing
1.removal of AA
2. Cutting into small pieces
3.addition of chemical (phosphate)
what are the 4 types of mutation and what are they ?
- Silent: dif codon but still same AA
- Missense: diff codon; dif AA
- Nonsense: early stop codon due to diff codon
- Frame shift: adding or removing which shift the whole reading frame
what is post translational processing ?
mods that happen to proteins after translation
