In eukaryotes, ribosomes become associated with endoplasmic reticulum membranes when
A) a signal sequence on the mRNA interacts with a receptor protein on the membrane.
B) a signal sequence on the ribosome interacts with a receptor protein on the membrane.
C) a signal sequence at the amino terminus of the protein being synthesized interacts with a receptor protein on the ribosome.
D) a signal sequence on the protein being synthesized interacts with a signal recognition particle and both bind to the endoplasmic reticulum.
E) the messenger RNA passes through a pore in the membrane.

Question

Quizplus · Accepted Answer

Ribosomes become associated with endoplasmic reticulum membranes when a signal sequence on the protein being synthesized interacts with a signal recognition particle and both bind to the endoplasmic reticulum. This is known as the SRP pathway and is responsible for directing the synthesis and processing of many secreted and membrane-bound proteins. The signal recognition particle recognizes the signal sequence on the protein and binds to the ribosome, pausing translation until it can deliver the ribosome to the endoplasmic reticulum membrane. Once there, the nascent protein is threaded through a protein translocation channel in the membrane for further processing and modification.

In Eukaryotes, Ribosomes Become Associated with Endoplasmic Reticulum Membranes When