The role of BiP in protein folding was briey described in this chapter. Answer the following questions
about observations and situations involving BiP.
(a) BiP is found in high concentration in the lumen of the ER but is not present in signicant concentrations elsewhere in the cell. How do you think this condition is established and maintained?
(b) If the gene coding for BiP acquires a mutation that disrupts the protein’s binding site for hydrophobic amino acids, what kind of impact might this have on the cell?

Explanation:

(a) The distinction between proteins sent out from and those held in the ER has all the earmarks of being represented by two unmistakable sorts of focusing on successions that explicitly mark proteins as either bound for transport to the Golgi or bound for maintenance in the ER. Numerous proteins are held in the ER lumen because of the nearness of the focusing on grouping Lys-Asp-Glu-Leu (KDEL, in the single-letter code) at their carboxy end. In the event that this succession is erased from a protein that is regularly held in the ER (e.g., BiP), the transformed protein is rather moved to the Golgi and emitted from the cell. On the other hand, the expansion of the KDEL arrangement to the carboxy end of proteins that are typically discharged makes them be held in the ER. The maintenance of some trans membrane proteins in the ER is comparatively directed by short C-terminal successions that contain two lysine deposits (KKXX sequences)

(b) Proteins are large molecules composed of folded chains of amino acids. Every protein has a unique shape and that shape determines the things it does. You could think of them as keys that fit into certain locks around the body Proteins do lots of different things around the body, including speeding up biological processes, recognizing antibodies, providing structure to certain body parts, transporting substances, regulating genes, and responding to signals inside and outside the body Proteins range in size from small ones, such as insulin - only 51 amino acids long, to extremely large ones, such as titin almost 27,000 amino acids long. No matter their size, they must be folded into a particular shape in order to function. Sometimes, though, things go wrong and cause the protein to unfold

the nitrogen cycle provides nitrogen to the ecosystem from the atmosphere, ground and oceans. nitrogen is an important component of complex molecules such as amino acids and nucleotides, which lead to the creation of proteins and dna, the building blocks of all life. plants absorb nitrogen in the form of ammonium, nitrate ion and, on rare occasions, as amino acids. animals receive nitrogen necessary for biological processes from feeding on living or dead organic matter.