Chapter 8

Question 1

What is the Endomembrane system composed of?

Answer 1

ER, Golgi complex, and dissolves, lysosomes, and vacuoles

Question 2

What is the biosynthetic pathway?

Answer 2

Proteins are synthesized in the ER, modified a Golgi complex and transported to various destinations

Question 3

What is the secretory pathway?

Answer 3

Protein synthesized in ER are discharged from cell

Question 4

What is the endocytic pathway?

Answer 4

Materials move from outer surface of cell to compartments, endosomes and lysozymes

Question 5

What are the two secretion modes?

Answer 5

Consecutive secretion and regulated secretion

Question 6

What is consecutive secretion?

Answer 6

Materials transported in secretary vesicles and discharged in continual manner

Question 7

What is regulated secretion?

Answer 7

Materials are stored in vesicles and discharged in response to stimulus

Question 8

Where does regulated secretion occur?

Answer 8

Endocrine cell (hormones), pancreatic acinar cells (digestive enzymes), and never cells (neurotransmitters)

Question 9

How can secreted materials be stored?

Answer 9

In large, densely packed, membrane-bound secretory granules

Question 10

How are proteins, lipids, and complex polysaccharides transported through the cell?

Answer 10

Along the biosynthetic or secretory pathways

Question 11

What is autoradiography?

Answer 11

Visualize biochemical processes by radioactively labelling molecules

Question 12

What did autoradiography show?

Answer 12

Endoplasmic reticulum as site where secretory proteins synthesis occurred

Question 13

What are GFPs?

Answer 13

Fluorescent proteins, allows microscope’s viewing of protein movement in living cells

Question 14

What is the endoplasmic reticulum?

Answer 14

Network of membranes that penetrates much of cytoplasm and has a lumen separated from cytosol by ER membrane

Question 15

What are the two compartments of the ER membrane?

Answer 15

The rough ER and the smooth ER

Question 16

Describe the rough ER

Answer 16

Ribosomes bound to cytosolic surface, flattened sacs connected to neighbors, continuous with outer membrane of nuclear envelope

Question 17

Describe smooth ER

Answer 17

Lacks ribosomes, membranes highly curved and tubular, continuous with RER

Question 18

What is the SER functions?

Answer 18

1. Steroid hormone synthesis in endocrine cells of the gonad an adrenal cortex
2. Detoxification of organic compounds in liver
3. Calcium ions sesquastation and regulated release

Question 19

What is the starting point of biosynthetic pathways for secretory proteins?

Answer 19

The RER

Question 20

What is co-translational translocation?

Answer 20

Proteins are synthesized at our ER and released into ER lumen

Question 21

The ER bound ribosomes synthesize what?

Answer 21

Integral membrane proteins

Question 22

How are integral membrane proteins synthesized?

Answer 22

Co translationally, and hydrophobic transmembrane segments are shunted from translocation into lipid bilayer

Question 23

What are tail anchored proteins?

Answer 23

Lack signal sequence, are synthesized in cytoplasm, and targeted to ER through interactions with proteins in GET pathway

Question 24

How do membranes arise?

Answer 24

From other membranes

Question 25

What modifies membranes?

Answer 25

Enzymes

Question 26

Nearly all proteins produced on RER become what?

Answer 26

Glycoproteins

Question 27

Accumulation of miss folded proteins triggers what kind of response?

Answer 27

Unfolded protein response

Question 28

Are misfolded proteins destroyed?

Answer 28

Yes

Question 29

What is the first step in vesicular transport?

Answer 29

ER to Golgi complex

Question 30

Where are transport vesicles formed?

Answer 30

The RER has specialized exit sites

Question 31

What is the Golgi complex?

Answer 31

Stack of flattened cisternae

Question 32

What does the cis face of the Golgi face?

Answer 32

The ER

Question 33

Where is the trans face of the Golgi?

Answer 33

The opposite side of the stack

Question 34

What is the cis Golgi Network?

Answer 34

Functions to sort proteins for the ER or next Golgi station

Question 35

What is the trans Golgi network?

Answer 35

Functions in sorting proteins to plasma membrane or various intracellular destinations

Question 36

Where does assembly of carbohydrates take place?

Answer 36

In the Golgi complex

Question 37

Describe the vesicular transport model

Answer 37

Cargo shuttled from CGN to TGN in vesicles

Question 38

Describe cisternal maturation model

Answer 38

Each cistern matures as it moves from cis to trans

Question 39

How are materials carried between compartments in vesicle transport?

Answer 39

Using coated vesicles

Question 40

What are the two functions of protein coats?

Answer 40

1. Cause membrane to curve and form vesicle 2. Select components to be carried by vesicle

Question 41

What are COPII coated vesicles?

Answer 41

Move materials from ER forward to ER GIC intermediate compartment and Golgi complex

Question 42

What are COPI coated vesicles?

Answer 42

Move materials from ERGIC and Golgi backward to ER or from trans Golgi to cis Golgi cisternae

Question 43

What are clathrin-coated vesicles?

Answer 43

Move materials from TGN to endosomes, lysosomes, and plant vacuoles

Question 44

What do clathrin coated vesicles contain?

Answer 44

An outer lattice composed of clathrin, an inner shell composed of GGA adaptor proteins, and a G protein

Question 45

What are Rabs?

Answer 45

A family of small G proteins which cycle between an active GTP bound state and an inactive GDP bound state

Question 46

What are SNAREs?

Answer 46

Constitute family of proteins localized to specific sub cellular compartments, integral proteins that bring vesicle and target compartment in close contact

Question 47

Where are v- SNAREs found?

Answer 47

Transport vesicles

Question 48

Where are t-SNAREs found?

Answer 48

Target compartments

Question 49

What is exocytosis?

Answer 49

Discharge of a secretory vesicle or granule after fusion with plasma membrane

Question 50

What is exocytosis triggered by?

Answer 50

Increase in calcium

Question 51

What is a fusion pore?

Answer 51

Contacts between vesicle and plasma membranes

Question 52

What are lysosomes?

Answer 52

Single celled organisms and phagocytic white blood cell digest ingested materials by fusing phagosomes in lysozymes

Question 53

What is a phagophore?

Answer 53

Envelopes an organelle to produce a double membrane sequestering vesicle

Question 54

What is a benefit of autophagy?

Answer 54

Helps protect organism from intracellular threats and may play a role in prevention of certain types of cancers

Question 55

What are the two categories of endocytosis?

Answer 55

1. Bulk phase endocytosis 2. Receptor mediated endocytosis

Question 56

What is bulk phase endocytosis?

Answer 56

Nonspecific uptake of extra cellular fluid

Question 57

What is receptor mediated endocytosis?

Answer 57

Brings about uptake of specific extra cellular macromolecules following binding to receptors on the surface of the plasma membrane

Question 58

What is dynamin?

Answer 58

G protein required for fission of vesicles from membrane on which it forms, self assembles into helical collar

Question 59

After internalization, vesicle bound materials are transported in vesicles and tubules known as what?

Answer 59

Endosomes 

Question 60

What are low density lipoprotein’s?

Answer 60

A complex of cholesterol and proteins, LDL receptors are transported to plasma membrane and bound to a coated pit

Question 61

What are peroxisomes?

Answer 61

Small, membrane enclosed organelles that contain enzymes involved in a variety of metabolic reactions, including several aspects of energy metabolism