Leys - Intracellular Compartments and Protein Sorting

Question 1

Which 2 intracellular compartments make up roughly 54% and 22% of the cell volume respectively

Answer 1

cytosol and mitochondria

Question 2

Proteins that have crossed a membrane are no longer ___________ inside the cell; they must _________ the membrane to get back inside

Answer 2

topologically

recross

Question 3

Vesicles move from compartment to compartment within a cell by _______ _____ and _________ ________

Answer 3

budding off

membrane fusion

Question 4

Many proteins have _______ __________ at their amino terminus that direct the proteins to cross the membrane; fewer proteins have ______ signal sequences

Answer 4

signal sequences

internal

Question 5

The nucleus is surrounded by a double _____ membrane _____; however nuclear ______ allow molecules, including portents to pass from the cytosol into the nucleus and back

Answer 5

lipid bilayer

pores

Question 6

Larger proteins pass through nuclear pores by an _______ process

Answer 6

active

Question 7

Nuclear _____ receptors bind to nuclear ________ signals found on some nuclear bound proteins and facilitate transport into the ________

Answer 7

import
transport
nucleus

Question 8

It generally requires _______ signals to transport proteins from the ________ into the lumen of the __________

Answer 8

multiple
cytosol
mitochondria

Question 9

There are multiple _______ ________ in the mitochondrial membrane; each interacts with a specific set of _______

Answer 9

protein translocators

proteins

Question 10

Transport of protein into the mitochondria requires ______

Answer 10

energy

Question 11

Proteins enter ________ using a mechanism similar to mitochondria entry

Answer 11

perioxiosomes

Question 12

Proteins travel from the _______ ______ through the _____ to many sites

Answer 12

endoplasmic reticulum

golgi

Question 13

A _______ ______ protein binds to the signal sequence during ________ and directs nascent peptide to the ________ membrane

Answer 13

signal recognition
translation
ER

Question 14

Proteins bound for the mitochondria are translated in the _____ and then transported through the _________ membrane; this process requires _____

Answer 14

cytosol
mitochondria
ATP

Question 15

Proteins that are headed into or through the _____ are transported through the ____ membrane during _________; this process does not require additional energy

Answer 15

ER
ER
translation

Question 16

_________ ___________ of proteins in the ER helps direct them to their ultimate location

Answer 16

carbohydrate modification

Question 17

The “default pathway” if there are no other signals directing the protein to other locations, is to send the protein to the _____ ______

Answer 17

cell surface

Question 18

In regulated secretory pathway cells store proteins in _______ vesicles until they are signaled to release them from the cell by _____ of the vesicle with the ______ _______

Answer 18

secretory
fusion
cell membrane

Question 19

True of False

The rough ER, smooth ER + golgi, and the nucleus make up only 21% of the cell volume

Answer 19

True; the cytosol and mitochondria make up 76% of the cell volume

Question 20

True or False

There is a greater volume of lysosomes than there are peroxisomes or endosomes

Answer 20

False; lysosomes, peroxisomes, and endosomes each make up 1% of the cell volume

Question 21

True or False

The relative intracellular compartment composition of a cell can change dependent upon the function of the cell

Answer 21

True; a cell responsible for energy metabolism will contain more mitochondria; while a cell responsible for waste excretion will contain more lysosomes, etc.