Problem:
Question 1: What do miRNAs and siRNAs have in common? What is different about them? What is their effect on gene expression?
Question 2: Why do cell biologists commonly apply siRNAs to cells in culture? What effect does siRNA have on protein expression, and how do they achieve that effect?
Question 3: Why do cells have few E1 ubiquitin-activating enzymes and many E3 ubiquitin ligases?
Question 4: How can a protein's stability change under different cellular conditions??
Question 5: Why would the proteosome not degrade a protein that is poly-ubiquitylated?
Please provide description of your answers.