1. Higher eukaryotes express multiple molecular chaperones (heat shock proteins). Define chaperone types (at least three) and differentiate their functional roles and action mechanisms. 2. What are the significance of disulfide bond formation in the endoplasmic reticulum (ER) in eukaryotes and the underlying mechanisms? 3. Define unfolded protein response (UPR) in the ER and describe the mechanisms involved in the process. 4. Describe (1) the mechanisms underlying unfolded protein response (UPR) in the mitochondria, and the significance and mechanisms of mitochondrial quality control..