Lecture 4

Question 0

Receptor-mediated Endocytosis

Answer 0

• receptors aggregate in patches on surface of cell membrane

- associated with coated pits before or after binding with ligands

Question 1

Fluid-phase Endocytosis

Answer 1

• non-selective

- forms vesicles containing extracellular fluid + contents

Question 2

Clathrin

Answer 2

• coated pits involved in selective endocytosis
• coats secretory vesicles
• triskelion subunits interlock to form geometric shapes
• anchors transmembrane receptors at the site of forming vesicles

Question 3

hsp70

Answer 3

• heat shock proteins, protective proteins
• help proteins fold or keep unfolded until ready to fold
• chaperone proteins

Question 4

Coatamers

Answer 4

• coat vesicles being transported between Golgi stacks (COPI)
• coat being transported from ER to CGN (COPII)

Question 5

SNARE-v and SNARE-t

Answer 5

• v, found on vesicle

- t, found on membrane

Question 6

Fusion of Vesicle and target membrane

Answer 6

• NSF

- SNAPS (soluble NSF attachment protein)

Question 7

Signal Recognition Particle (SRP)

Answer 7

• attaches to signal sequence (20AA) and prevent further elongation
• 6 proteins, 7S segment of RNA

Question 8

BiP

Answer 8

• a Hsp70, pulls the polypeptide chain through channel into ER lumen
• aids in folding and assembly of multisubunit proteins

Question 9

GPI

Answer 9

• anchored to luminal leaflet of ER, they will be exposed to outside of cell
• proteins destined to plasma membrane will anchor to these

Question 10

Proteasomes

Answer 10

-degrade severely misfolded proteins, sent ack through translocon

Question 11

Flippase Proteins

Answer 11

-phospholipids that are to be located in luminal leaflet of ER membrane transferred by

Question 12

Cisternae

Answer 12

-stacks of flattened sacs on Golgi

Question 13

Cis-Golgi Network

Answer 13

• entry face
• adjacent to the ER
• receives cargo within transport vesicles from ER

Question 14

Trans-Golgi Network

Answer 14

• exit face

- faces away from nucleus

Question 15

Glycosylation

Answer 15

• process of adding and modifying carbs attached to glycoproteins and proteoglycans received from ER
• includes mod of N-linked oligosaccharides on glycoproteins
• utilizes glycosyltransferase enzymes

Question 16

O-linked Glycosylation

Answer 16

• addition of carbs to serine and threonine

- Golgi

Question 17

Synthesis of Sphingomyelin and Glycosphingolipids in…

Answer 17

-Golgi

Question 18

Anterograde Trafficking

Answer 18

-from cis face of Golgi to trans

Question 19

Retrograde Traffiking

Answer 19

-from cis face of Golgi back to RER

Question 20

Facultative Secretion

Answer 20

• some cargo stored in secretory vesicles and released in response to specific extracellular signal
• such as hormone or neurotransmitter

Question 21

Constitutive Secretion

Answer 21

• secreted continuously and don’t require signal
• newly synthesized lipids
• proteins to membrane or extra matrix

Question 22

Targeting signal for lysosomal enzymes is…

Answer 22

• mannose-6-phosphate

- these residues found on glycoproteins that will become acid hydrolyses

Question 23

Primary Lysosome

Answer 23

-just budded of TGN

Question 24

Secondary Lysosoes

Answer 24

• fused wit phagosome

- contains ATPase-H pump to create pH 5 internal environment

Question 25

Residual Body

Answer 25

-remnants of a secondary lysosome with undigested materical

Question 26

Early Endosome

Answer 26

-endocytic vesicle with pH of 7.3-7.4

Question 27

Late Endosome

Answer 27

-endocytic esicle fused with lysosome with pH of 5