lect 17 a Compartments of Euaryotic Cells

Question 1

Vesicular Transport -

Answer 1

Secretory Pathways

Question 2

Secretion-

__________ and other macromolecules produced in the ER are often ________ from the cell through the process of __________. - ___________

Answer 2

proteins

exported

secretion

exocytosis

Question 3

Transport from the _____ to the Golgi and from the Golgi to the ____ ____ is mediated by _____ ______.

Answer 3

ER

Plasma membrane

coated vesicles

Question 4

______ synthesized on the ___ ___ ___ are usually further modified in the lumen of the ER and in the ____ before they become functional and are _______.

Answer 4

Proteins

RER

Golgi

secreted.

Question 5

Modification of Proteins-

in the ER-

Answer 5

• formation of disulfide bonds
• glycosylation—> glycoproteins

Question 6

Modification of Proteins

In the Golgi:

Answer 6

• oligosaccharide processing

Question 7

Glycosylation of Polypeptides in the ER:

Most proteins synthesized on the ___ ___ are _____ on the _____ side.

Answer 7

ER

glycosylated

lumenal

Question 8

N- Linked Glycosylation

Answer 8

14 - sugar oligosaccharide added to asparaing side chains as they enter the lumen of the ER.

Question 9

Glycosylation of Polypeptides in the ER.

Enzyme-

Answer 9

oligosaccharyl transferase

Question 10

Glycoslation of Polypeptides in the ER.

oligosaccharide donor-

Answer 10

dolichol phosphate ( a membrane lipid)

Question 11

ER- Golgi Transport-

Some proteins made in the ER stay in the ER- ______?

Answer 11

ER resident proteins

Question 12

Er retention signal -

Answer 12

four amino acid sequence

recognized by a membrane-bound receptor protein in the ER and Golgi membranes

ER resident proteins that escape to the Golgi are returned to the ER.

Question 13

ER- Golgi Transport

Most proteins made in the ___ ___ are destined for other compartments and are transported from the __ ___ to the _____?

Answer 13

ER

ER

Golgi

Question 14

ER- Golgi Transport

Mediated by _______ budding from ______ -____ areas of the ER?

Answer 14

vesicles

ribosome- free

Question 15

Two pathways

Foward pathway-

Answer 15

• no transport signal required ( default pathway)
• mediated by COP-coated vesicles
• proteins must be properly folded before they can enter the vesicles
• retention in the ER-mediated by chaperone proteins.

Question 16

Return pathway

Answer 16

• required transport signal- ER retention signal
• returns ER- resident proteins to the ER
• Mediated by COP - coated vesicles
• retention in the ER mediated by chaperone proteins.