For membrane-associated proteins, the consensus sequence _______ is found on the inchoate (new) polypeptide and ______ to halt.
a. pribnow, replication
b. signal peptidase, transcription
c. stop-transfer peptide, transcription
d. stop-transfer sequence, translation
e. stop-transfer sequence, translation
I thing the answer is "e". please check.
The answer is indeed option e. "stop-transfer sequence, translation". To understand why, let's break down the question and consider each option:
a. pribnow, replication - The Pribnow box is a consensus sequence found in the promoter region of bacterial DNA, not related to membrane-associated proteins.
b. signal peptidase, transcription - Signal peptidase is an enzyme involved in the cleavage of signal peptides during protein targeting, while transcription refers to the synthesis of RNA from a DNA template. These terms are not directly related to the consensus sequence mentioned in the question.
c. stop-transfer peptide, transcription - Stop-transfer peptide refers to a type of signal peptide that halts translocation across the membrane, but the process being referred to in the question is not transcription.
d. stop-transfer sequence, translation - The stop-transfer sequence, also known as a hydrophobic stop-transfer anchor sequence, is a consensus sequence found on the inchoate polypeptide (nascent peptide) chain during translation. This sequence signals the ribosome to halt translocation of the protein across the membrane, anchoring it in the membrane instead.
e. stop-transfer sequence, translation - This is the correct answer. As explained above, the stop-transfer sequence is found on the nascent polypeptide chain during translation, and it signals the ribosome to halt translocation.
Thus, the correct answer is e.