MSCI 660 INTRACELLULAR MEMBRANE
TRAFFIC AND CELLULAR SORTING 2026
GOLGI AND ER FUNCTION DRILL PACK
ANSWER SHEET
◉ What is the primary function of the Rough Endoplasmic
Reticulum (RER)?
Answer: Synthesis of soluble and transmembrane proteins for the
endomembrane system.
◉ What is the main role of the Smooth Endoplasmic Reticulum
(SER)?
Answer: Phospholipid synthesis and detoxification.
◉ What is a signal sequence in protein sorting?
Answer: A stretch of amino acid sequence in a protein that directs it
to the correct compartment.
◉ What are the two main types of protein sorting?
Answer: Post-translational sorting and co-translational sorting.
◉ Where do proteins undergo post-translational sorting?
, Answer: In the cytosol after being fully synthesized.
◉ What is the default location for cytosolic proteins?
Answer: Cytosol, unless they have a sorting signal.
◉ How are proteins sorted to the nucleus?
Answer: By a nuclear localization signal that directs them through
nuclear pores.
◉ What happens if a nuclear localization signal is mutated?
Answer: The protein remains in the cytosol instead of entering the
nucleus.
◉ What is the role of sorting receptors?
Answer: They recognize signal sequences and facilitate the transport
of proteins to their destinations.
◉ What types of proteins are imported into peroxisomes?
Answer: Folded proteins that contain a peroxisomal import signal.
◉ What is the function of peroxisomes?
Answer: Contain enzymes for oxidative reactions and detoxify
toxins.
TRAFFIC AND CELLULAR SORTING 2026
GOLGI AND ER FUNCTION DRILL PACK
ANSWER SHEET
◉ What is the primary function of the Rough Endoplasmic
Reticulum (RER)?
Answer: Synthesis of soluble and transmembrane proteins for the
endomembrane system.
◉ What is the main role of the Smooth Endoplasmic Reticulum
(SER)?
Answer: Phospholipid synthesis and detoxification.
◉ What is a signal sequence in protein sorting?
Answer: A stretch of amino acid sequence in a protein that directs it
to the correct compartment.
◉ What are the two main types of protein sorting?
Answer: Post-translational sorting and co-translational sorting.
◉ Where do proteins undergo post-translational sorting?
, Answer: In the cytosol after being fully synthesized.
◉ What is the default location for cytosolic proteins?
Answer: Cytosol, unless they have a sorting signal.
◉ How are proteins sorted to the nucleus?
Answer: By a nuclear localization signal that directs them through
nuclear pores.
◉ What happens if a nuclear localization signal is mutated?
Answer: The protein remains in the cytosol instead of entering the
nucleus.
◉ What is the role of sorting receptors?
Answer: They recognize signal sequences and facilitate the transport
of proteins to their destinations.
◉ What types of proteins are imported into peroxisomes?
Answer: Folded proteins that contain a peroxisomal import signal.
◉ What is the function of peroxisomes?
Answer: Contain enzymes for oxidative reactions and detoxify
toxins.
