Lecture 20: Transmembrane Proteins, Golgi, COP

Question 1

Options for protein targeted in the ER lumen after being synthesized

Answer 1

1. Retained in the ER lumen, if that is where it functions
2. It is transported from ER to Golgi complex for further modification and can even go outside the cell or to other cellular organelles

Question 2

The Golgi apparatus receives _____________

Answer 2

Proteins and lipids from the ER and sorts them to other organelles, plasma membrane, or cell exterior

Question 3

Material moves from ER to Golgi to other in a ______

Answer 3

Proximal to distal direction

Question 4

Trans Golgi network (TGN) is the

Answer 4

Where substances exit in the form of smaller detached vesicles. Sorts protein into different types of vesicles

Question 5

Cis Golgi network (CGN) is the

Answer 5

Stack at the end of the organelle where substances enter from the endoplasmic reticulum. Acts as a sorting station

Question 6

Structure of Golgi:

Answer 6

• smooth, flattened disk
• 8 or fewer cistern are/stack - range from few to 1000s of stacks per cell
• curved like shallow bowl
• shows polarity: cis-medial-trans
• cisternae are biologically unique
• membrane supported by protein skeleton
• scaffold linked to motor proteins that direct movement of vesicles into and out of golgi

Question 7

Golgi is the ______________ of the cell

Answer 7

Processing plant

Question 8

Golgi is involved in synthesis of __________, and of modification of ________ and _______

Answer 8

Polysaccharides
Proteins
Lipids

Question 9

How are proteins modified in the Golgi? And where to the fully processed proteins go?

Answer 9

Step-wise
TGN

Question 10

Consitutive secretory pathway

Answer 10

Mucin secretion

Question 11

Regulated secretory pathway

Answer 11

Release fo insulin and neurotransmitters

Question 12

Cystic fibrosis is caused by…

Answer 12

Mutation in the CFTR gene, the most common mutation is triangleF508, deletion of three nucleotides

Question 13

What are the function of coat proteins?

Answer 13

Help form the vesicle
Help select cargo

Question 14

What do coat proteins do to vesicles?

Answer 14

They transfer vesicles from ER to Golgi and between Golgi sub compartments

Question 15

What are COPI and COPII? (Coat protein complex)

Answer 15

Protein complexes that assembles on the cytosol if surface of donor compartment membranes at sites where budding takes place

Question 16

COPI-coated vesicles move in which direction?

Answer 16

retrograde

Question 17

COPII-coated vesicles move in which direction?

Answer 17

Anterograde

Question 18

Lysosomes features

Answer 18

• digestive organelles
• size: 25 nm to 1 microm
• internal pH of 4.6
• contains hydrolysis enzymes: acid hydrolysis
• lysosomal membrane is composed of glycosylated proteins that act as a protective lining next to acidic lumen