Question

1st attempt
how are proteins destined to function in the er retained there?
choose one:
they are embedded in the er membrane by a transmembrane a helix.
they are anchored to dolichol in the er membrane.
they retain their n - terminal er signal sequence.
they bind to chaperones within the er.
they contain a c - terminal er retention signal.

Explanation:

Proteins destined for the ER are retained there mainly due to the presence of a C - terminal ER retention signal, such as the KDEL sequence in mammals. This signal allows them to be recognized and retrieved if they accidentally escape the ER. Chaperones assist in protein folding but not the main mechanism for retention. Transmembrane helices are for membrane - bound proteins, not general retention. Dolichol is involved in glycosylation and not retention. Retaining the N - terminal signal sequence is for targeting to the ER, not retention.

Answer:

They contain a C - terminal ER retention signal.