Intro to Cell Biology: Protein Transport Mechanisms

These flashcards cover key concepts and mechanisms related to protein transport within cells as discussed in the cell biology lecture.

What are the three mechanisms by which proteins are transported into organelles?

Proteins are transported into organelles by three mechanisms.

Where are proteins made before being transported to specific organelles?

Proteins are made in the cytosol before being transported to specific organelles.

What happens to proteins as they are transported across membranes?

Proteins are usually unfolded when transported across membranes.

What is a key requirement for mitochondrial proteins?

Mitochondrial proteins must cross both the outer and inner membranes.

How are mitochondrial proteins imported into the mitochondria?

Mitochondrial proteins are imported as unfolded precursor proteins.

What role do signal sequences play in protein transport?

Signal sequences are important for the transport of proteins and are recognized by import receptor proteins.

What type of proteins must the ribosomes in 'rough' ER be directed by?

Ribosomes are directed by mRNA encoding proteins with a signal sequence.

How does the Signal Recognition Particle (SRP) assist in protein translocation?

The SRP binds to the mitochondrial protein’s signal sequence and directs the ribosome to the ER membrane.

What is the function of the stop transfer sequence in membrane proteins?

The stop transfer sequence tells the translocator protein to leave the protein embedded in the membrane.

What occurs after a protein is made and directed into the ER?

After a protein is made and directed into the ER, it can be trafficked to exit the cell.