Question

In the absence of a signal sequence, a newly synthesized protein localizes to the

A) mitochondria.
B) cytoplasm.
C) peroxisome.
D) nucleus.
E) plasma membrane.

Answer 1

When a newly synthesized protein lacks a signal sequence, it remains in its default location, the cytoplasm, as specialized organelles require unique signal sequences to direct the protein to them.

Step-by-step explanation:

In the absence of a signal sequence, a newly synthesized protein will localize to the cytoplasm. Signal sequences are like a protein’s “train ticket” to various cellular destinations such as mitochondria, the nucleus, or the endoplasmic reticulum. Without this ticket, the default location for a protein is where it is synthesized, which is in the cytoplasm. This cytoplasmic localization occurs because other specialized organelles and compartments require these unique signal sequences for protein import. Since such sequences are not present, the protein remains in the cytoplasm where translation occurs.