Term
| a ribosome has 3 binding sites for tRNA. Name them please. |
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Definition
P site - holds the tRNA that carries the growing polypeptide chain
A site - holds the tRNA that carries the next amino acid to be added to the chain
E site - the exit site, where discharged tRNAs leave the ribosome
[image] |
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Term
| What are the three stages of translation |
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Definition
Initiation
Elongation
Termination
all requiring protein factors |
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Term
| Describe the Translation initiation process |
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Definition
1. a small ribosomal subunit binds with mRNA and the initiator tRNA
2. the small subunit moves along the mRNA until it reaches the start codon (AUG)
3. initiation factors (proteins) bring in the large subunit that completes the translation initiation complex
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Term
| What end (5' or 3') does translation start at? |
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Definition
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Term
| elongation (amino acids are added one by one to the preceding amino acid) occurs in 3 steps: |
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Definition
codon recognition
peptide bond formation
translocation |
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Term
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Definition
| a stop codon in the mRNA reaches the A site of the ribosome, the A site accepts a protein (a release factor) which causes the addition of a water molecule instead of an amino acid...polypeptide chain released |
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Term
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Definition
| a ribosome that can translate a single mRNA simultaneously enabling a cell to make many copies of a polypeptide very quickly |
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Term
| Polypeptides destined for the ER or for secretion are marked by a ____ _____. |
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Definition
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Term
| post-translational modification |
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Definition
some polypeptide are activated by enzymes that cleave them
others form subunits of a protein
many are glocysylated (roteins are modified by the addition of carbohydrates (glycosylation) to specific amino acids in the peptide chain. One of the most common modifications is to attach an oligosaccharide (oligo means "few"; saccharide means "sugar" or "carbohydrate") to the growing peptide) |
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Term
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Definition
| help proteins fold correctly in the cell. Most chaperones use successive rounds of ATP hydrolysis to continually bind and release newly synthesized proteins until they are properly folded. |
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