Membrane proteins and protein localization

Question 1

Growth factors might

Answer 1

stimulate cancer cells

Question 2

Eukaryotic cells are separated by

Answer 2

intracellular membranes: endoplasmic reticulum,

Question 3

Proteins that are located in the membrane

Answer 3

transporters, anchors, receptors, enzymes

Question 4

Some proteins

Answer 4

help certain substances pass and make certain substances not pass

Question 5

glycoproteins

Answer 5

polypeptides that have polysacharide chains attached to them to

Question 6

Passing of substances from one vesicle to another (interconversion)

Answer 6

donor compartment, budding, fusion, target compartment

Question 7

many virus particles (ej virions) can be

Answer 7

wrapped in a lipid bilayer coat and enter into the cytosol

Question 8

Golgi apparatus and endoplasmic reticulum

Answer 8

proteins from the endoplasmic reticulum are transferred into golgi apparatus

Question 9

Interconversion

Answer 9

Intracellular membrane structures build and pinch off and fuse with other such structures

Question 10

all the contents inside of the cell and the extracellular space are

Answer 10

topologically equivalent

Question 11

exocytosis

Answer 11

a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane.

Question 12

during exocytosis

Answer 12

vesicle’s membrane is donated to the receptor’s membrane

the membrane protects its contents through a lipid external layer

Question 13

two processes with opposite way of working

Answer 13

exocytosis and endocytosis

Question 14

Lysosome

Answer 14

an organelle in the cytoplasm of eukaryotic cells containing degradative enzymes enclosed in a membrane.

(hydrolytic enzymes)

sites of degradation

Question 15

Macrophages

Answer 15

destroy bacteria through endocytosis

Question 16

How are secreted proteins made?

Answer 16

A pool of polyribosomes is in the cytoplasm (the corresponding is defined by the function of the polypeptide)

Question 17

Signal sequence is a

Answer 17

zipcode for the protein

Question 18

Secretory pathway

Answer 18

a series of steps a cell uses to move proteins out of the cell, a process known as secretion. The path of a protein destined for secretion has its origins in the rough endoplasmic reticulum, a membrane-bound compartment in the cell.

Question 19

Lumen

Answer 19

inside space of a cellular component or structure, such as the endoplasmic reticulum —- “an opening”

Question 20

Highly hydrophobic segments

Answer 20

make the secretion of protein stop when such hydrophobic segment matches the transmembrane domain

Question 21

Glycosilation

Answer 21

reaction in which a carbohydrate, i.e. a glycosyl donor, is attached to a hydroxyl or other functional group of another molecule.

Question 22

Experiment…(?)

cell free protein synthesis - microsomes (ER) present

Answer 22

we have mRNA that encodes a protein; the translation process is finished and protein is synthesized;

will this protein is intended to be added to a microsome, it will no longer incorporate, because the struture is already closed.

tethering must be successful

Question 23

Interchanges between endomembranes

Answer 23

Endoplasmic reticulum () Golgi 
Golgi-> secretory vesicles-> cell exterior
Golgi->cell exterior
Golgi  late endosome  lysosomes, 
Golgi  early endosome -> cell excretor

Question 24

Early and Later endosomes

Answer 24

are the phases of an endosome during endocitosis

Question 25

Nascent peptides are pumped into

Answer 25

the Endoplasmic reticulum

Question 26

Proteins found in the nucleus

Answer 26

never passed through the endoplasmic reticulum

Question 27

ER is continuously

Answer 27

pinching off small vesicles

Question 28

Microsome

Answer 28

experimental artefact

Question 29

Do you need help during the fusion process? (When the vesicle starts to pinch off

Answer 29

Yes , enzymes called fusogenic help to make membranes join in order to form the new “sack”

Question 30

How do soluble proteins get into the protein?

Answer 30

They have a zip code address that transports then into nucleus.