Question

14). How, when, and where do the transmembrane proteins of the plasma membrane get imbedded into the membrane, and how do they get into the plasma membrane (their path).

Answer 1

Answer=

Transmembrane protein- Is a protein that goes from one side of membrane through to the other side of the membrane.

Many of them functions as gateways or "loading docks"to deny or permit the transport of specific substances across the biological membrane ,to get into the cell,or out of the cell as in case of waste byproducts.

TP is a polytopic protein that spans an entire biological membrane.

Alpha helical TP- Type I TP are anchored to the lipid membrane with a stop-transfer anchor sequence & have their N-terminal domains targeted to ER lumen during synthesis

Type II & III TP- anchored with a signal -anchor sequence ,with type II being targeted to ER lumen with its C-terminal domain.

while III -have N-terminal domains targetd to ER-lumen

Type IV TP- is subdivided into IV A -with their N terminal domains targeted to cytosol and IV-B with an N-terminal domain targeted to the lumen.