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51 Cards in this Set
- Front
- Back
Translation |
process of protein synthesis from an RNA template |
|
Codon |
3 bases |
|
Start codon in mRNA |
AUG (methionine) |
|
Reading direction |
5' to 3' |
|
Stop codons |
UAA - you are away UAG - you are gone UGA - you go away |
|
insertion or deletion of nucleotide |
Can result in frameshift mutation |
|
where do Modifications take place? |
Everywhere in eukaryotas |
|
codon - anticodon interaction |
Flexible than most base pairing |
|
Wobble |
third position in the codon can change without changing the AA in some cases allows one tRNA to translate more than one codon |
|
codon - anticodon pairing |
anticodon (3') 3-2-1(wobble) (5') ---------- (5') 1-2-3(wobble) (3') Codon |
|
Saber leer genetic code |
|
|
Types of Mutations |
1. point mutation 2. silent mutation 3. Missense mutation 4. Non sense mutation 5. Insertion (frameshift) 6. Deletion (frameshift) |
|
point mutation |
changing single nucleotide base |
|
silent mutation |
Change that specifies the same AA |
|
Missense mutation |
Change that specifies a different AA |
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Non sense mutation |
Change that produces a Stop codon |
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Insertion (frameshift) |
Addition of 1 or more bases |
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Deletion (frameshift) |
Loss of 1 or more bases |
|
Components required for protein synthesis |
1. AA 2. tRNA 3. Ribosomes 4. mRNA 5. Aminoacyl-tRNA synthetase |
|
Aminoacyl-tRNA synthetase |
Catalyses the attachment of AA with its corresponding tRNA forming aminoacyl tRNA there are 20 synthetases - 1 for each AA -some have proofreading activity (there recognized and correct) |
|
tRNA function |
form a covalent bond with a particular AA base pairing with a codon in mRNA |
|
tRNA nucleotidyltransferase |
an RNA polymerase that adds CCA sequence to the 3' of humans. It can synthesize a sequence with a template. |
|
rRNA |
Most abundant and stable RNA's Are proccessed in the nucleolus |
|
Ribosome |
Subcellular ribonucleoprotein complex on which protein synthesis occurs |
|
Cytoplasmic ribosomes in eukaryotic have 4 types of rRNA molecules |
60S --- 5S + 5.8S +28S 40S --- 18S ___________ 80S |
|
Prokaryotic ribosomes have 3 rRNA molecules |
50S --- 5S + 23S 30S --- 16S ________ 70S *mitochondrial are similar |
|
28S rRNA eukaryotes |
only one with enzymatic activity : peptidyltransferase activity |
|
Aminoacyl tRNA formation |
in the cytosol (not in the ribosome) |
|
Translation Initiation complex |
1. 40S and 60S units 2. mRNA 3. initiation factors (elFs) 4. Methionyl-tRNA (only tRNA recognized by the initiation factor elF-2 5. ATP and GTP 6. Kozak consensus sequence |
|
Reading direction of translation |
5' to 3' |
|
Initiation in Prokaryotes |
|
|
Elongation sites |
E - exit P - peptidol tRNA (formation of peptide bond) A - entry site (Aminoacyl- tRNA) |
|
Elongation |
only use GTP not ATP |
|
A site in Elongation |
GTP is hydrolized to GDP the binding comprises the second error checking |
|
Peptidyltransferase |
catalyze the peptide bond between A and P site |
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GTP used in translation |
Initiation: 1 GTP Elongation: ** Termination: 1GTP |
|
ATP used in translation |
only in initiation |
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polysome |
complez of ribosomes that translate at the same time |
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chaperones |
Prevent improper interactions from occurring in the poly peptide chain |
|
targeting sequences or signal sequences |
Amino acid sequences that determine where the proteins will be released |
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Synthesis of protein in the RER |
|
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Golgi complex |
*** |
|
Tetracycline |
Binds to the 30S subunit and inhibits binding ofaminoacyl-tRNA to the A site |
|
Cyclohexamide |
Inhibits the peptidyltransferase activity of the60S ribosomal subunit (eukaryotes) |
|
Chloramphenicol |
Binds to the 50S ribosomal subunit andinhibits peptidyltransferase |
|
Erythromycin |
Binds to the 50S ribosomal subunit and preventstranslocation |
|
Puromycin |
Causes premature chain termination by acting as aanalog of aminoacyl-tRNA (both) |
|
Streptomycin |
Binds to the 30S ribosomal subunit ofprokaryotes, thereby preventing formation of the initiationcomplex. It also causes misreading of mRNA |
|
Diphtheria Pertusis Toxin |
Secretes the A fragment (toxin) a ADP ribosyl transferase eEF-2 is inhibited - thus protein synthesis stops inactivation results in cell death Vaccination will prevent it |
|
Tay-Sachs Disease |
Ganglioside (Gm2) accumulates Mutation in gene encoding lysosomal enzyme this mutation lost of lysosomal function and death at an early age |
|
I cell Disease |
inherited lysosomal storage disorder Mutation post translational -mistargeting of enzymes to lysosomes In GNTPA gene coarse facil features, skeletal abnormalities and mental retardation |