Cellular Biology Chapter 15 (FINAL EXAM)

Which of the following statements about transport into mitochondria and chloroplasts is false?

After a protein moves through the protein translocator in the outer membrane of these organelles, the organelle diffuses in the lumen until it encounters a protein translocator in the innter membrane

Which of the following statements is true?

Chaperone proteins in the mitochondria facilitate the movement of proteins across the outer and inner mitochondrial membranes.

Which of the following statements about membrane-enclosed organelles is true?

In a typical cell, the area of the endoplasmic reticulum membrane far exceeds that area of plasma membrane

What is the role of the nuclear localization sequence in a nuclear protein:

It is bound by cytoplasmic proteins that direct the nuclear protein to the nuclear pore

Which of the following statements about peroxisomes is false?

Most peroximal proteins are synthesized in the ER

Which of the following statements about nuclear transport is true?

Nuclear pores have water-filled passages that small, water-soluble molecules can pass through in a nonselective fashion

Your friend works in a biotechnology company and has discovered a drug that blocks the ability of Ran to exchange GDP for GTP. What is the most likely effect of this drug on nuclear transport?

Nuclear transport receptors would be unable to release their cargo in the nucleus

You are interested in Fuzz, a soluble protein that functions within the ER lumen. Given that information, which of the following statements must be true?

Once the signal sequence from Fuzzy has been cleaved, the signal peptide will be ejected into the ER membrane and degraded.

Which of the following statements about the endoplasmic reticulum (ER) is false?

Proteins to be delivered to the ER lumen are synthesized on smooth ER

Which of the following statements is true?

The nuclear membrane is thought to have arisen from the plasma membrane invaginating around the DNA

Most proteins destined to enter the endoplasmic reticulum:

begin to cross the membrane while still being synthesized

Signal sequences that direct proteins to the correct compartment are:

encoded in the amino acid sequence and sufficient for targeting a protein to its correct destination

Where are the proteins in the chloroplast synthesized?

in both the cytosol and the chloroplast

In which cellular location would you expect to find ribosomes translating mRNAs that encode ribosomal proteins?

in the cytosol

Which of the following organelles is not part of the endomembrane system?

mitochondria

After isolating the rough endoplasmic reticulum from the rest of the cytoplasm, you purify the RNAs attached to it. Which of the following proteins do you expect the RNA from the rough endoplasmic reticulum to encode?

soluble secreted proteins/ER membrane proteins/plasma membrane proteins

A large protein that passes through the nuclear pore must have an appropriate:

sorting sequence, which typically contains the positively charged amino acids lysine and arginine

Proteins that are fully translated in the cytosol and lack a sorting signal will end up in:

the cytosol

Proteins that are fully translated in the cytosol do not end up in:

transport vesicles