Leys - Intracellular Compartments and Protein Sorting

Question 1

Proteins that have _______ a membrane are no longer topologically inside a cell. They must _______ the membrane to get back inside the cell.

Answer 1

crossed

recross

Question 2

Vesicles move from compartment to compartment within a cell by _______ and _______

Answer 2

budding off

membrane fusion

Question 3

Many proteins have signal sequences at their _______ that direct the proteins to _______. Fewer proteins have _______ signal sequences.

Answer 3

amino terminus
cross the membrane
internal

Question 4

The nucleus is surrounded by a _______, however _______ allow molecules, including proteins, to pass from the cytosol into the nucleus and back.

Answer 4

double lipid membrane bilayer

nuclear pores

Question 5

Larger proteins pass through nuclear pores by _______.

Answer 5

an active process

Question 6

_______ bind to _______ found on some nuclear bound proteins and facilitate transport into the nucleus.

Answer 6

nuclear import receptors

nuclear transport signals

Question 7

It generally requires multiple signals to transport proteins from the _______ into the _______.

Answer 7

cytosol

lumen of the mitochondria

Question 8

There are multiple _______ in the mitochondrial membrane. Each _______ interacts with a specific set of proteins.

Answer 8

protein translocators

translocator

Question 9

Transport of protein into the mitochondria requires _______.

Answer 9

energy

Question 10

Proteins enter _______ using a mechanism similar to _______.

Answer 10

peroxisomes

mitochondrial entry

Question 11

Proteins travel from the _______ through the _______ to many sites.

Answer 11

endoplasmic reticulum (ER)
golgi

Question 12

A _______ binds to the _______ during translation and directs the nascent peptide to _______.

Answer 12

signal recognition protein (SRP)
signal sequence
ER membrane

Question 13

Proteins bound for the mitochondria are translated in _______ and then transported through the _______. This process requires _______.

Answer 13

cytosol
mitochondrial membrane
ATP

Question 14

Proteins that are headed into or through the ER are transported through _______ during _______. This process requires _______.

Answer 14

ER membrane
translation
no additional energy

Question 15

_______ modification of proteins in the _______ helps direct them to their ultimate location.

Answer 15

carbohydrate

ER

Question 16

The “default pathway” if there are no other signals directing the protein to other locations is to send the protein to _______.

Answer 16

the cell surface

Question 17

In _______ pathway, cells store proteins in _______ until they are signaled to release them from the cell by _______ of the vesicles with the cellular membrane.

Answer 17

regulated secretory
secretory vesicles
fusion

Question 18

What are the major components of an animal cell?

Answer 18

• cytosol
• mitochondria
• rough and smooth ER
• golgi cisternae
• nucleus
• peroxisomes
• lysosomes
• endosomes