Question

21. which of the following mechanisms is used by cells to ensure that proteins are correctly localized to specific organelles, integrated into the plasma membrane or secreted?

a. proteins encode a sequence that act as a signal such as a nuclear localization signal( NLS) go target them appropriately

b. after translation, most proteins are transported by binding to chaperons in the cytosol which actively transport fhem.

c. proteins are usually synthesized by ribosomes that are pre localized to the place the protein will be needed

d. proteins become glysosylated in the rough ER and Golfi and only proteins with sugar modification are transported to their correct subcellular location.

e. any protein being synthesized is immediately inserted into a vesicle that coated with proteins that will target the vesicle to the correct compartment within the cell.

Answer 1

A nuclear localization signal or sequence (NLS) is generally positively charged (due to lysin or arginin) sequence which are coexpressed along with the protein that dictates its fortune to install the protein at what place. so option 1 is correct.

Chepron casused aggregation of proteins not involved in transportation

ribosomes are note present over cell membrane still in contains proteins in it so this statement is not correct

there are many proteins over cell membrane which are not glycosylated so this is neither correct