<prompt> Role of Ubiquitin in cell -Energy dependent protein foldingEnergy independent protein foldingEnergy dependent protein degradationEnergy independent protein degradation  <response>: Ans. is c i.e., Energy dependent protein degradation o There are two major enzyme systems responsible for degradation of damaged or unneeded proteins1 Ubiquitin-proteosome proteolytic pathway Defective protein is first covalently attached to ubiquitin. Covalent bond is formed between glycine a- carboxyl group of ubiquitin and lysine amino group of target protein. Ubiquitinated protein is then degraded in proteosomes by ATP dependent energy dependent mechanism.2 Lysomes Proteins are degraded by proteolytic enzymes which is energy independent non-energy dependent. 