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Protein Synthesis
Question | Answer |
---|---|
Which step is the rate limiitng step? | Initiation |
What is the 80S structure of the Eukaryotic ribosome composed of? | The 60S subunit and the 40S subunit |
What are polysomes? | Many ribosomes making protein from one mRNA at the same time |
What is at the 3' end of tRNA? | A CCA sequence where the amino acid will be covalently attached |
What does aminoacyl synthases do? | It activates the amino acid and catalyzes the covalent attachmen of the amino acid to the tRNA |
What site does the amino acids bind to on tRNA during elongation? Initiation? | The A site. Initiation it binds to the P site |
What is transloaction and does it require energy? | Results in the shift of the ribosome in respect to the message and requires GTP |
What are the chaperones and what do they do? | The chaperones are the Hsp(heat shock proteins) and they induce transcription. Also prevents misfolding of proteins. |
How does heme regulate translation of globin? | The heme can regulate a kinase that in trun phosphorylates an important initiation factor EIF2. It controls the rate of globin syntheses and heme can match its rate of synthesis to globin |
How is heat shock proteins related to cancer? | An excess of hsp can promote the growth of a tumor |
What binds to the signal sequence to causes a protein to pause in translation? | SRP will recognize the signal sequence and cause it to pause in translation. |
After a protein is paused in translation due to SRP where does it go? | SRP will take it to the cytosolic side of the ER and position it next to a channel called translocon |
What are Bip (binding proteins)? | Binding proteins are part of the family of Hsp70 and it prevents misfolding during translation. |
What important rRNA component does the 60S subunit have? | 28s rRNA has the enzymatic activity that is responsible for peptide bond formation. |
How are proteins targeted where to go? | Proteins get directed to where they need to go with the information in the primary sequence |
What enzyme causes a disulfide formation in the lumen of the rough endoplasmic reticulum? | The enzyme disulfide isomerase |
If there is no intiation sequence at the N terminus where could it be? | There can be an internal intial sequence |