Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Molecules and cells - M.G > Glycosylation > Flashcards

Glycosylation Flashcards

You may prefer our related Brainscape-certified flashcards:
Organic Chemistry 101 flashcards
1
Q

What is glycosylation?

A

The addition of polysaccharides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where does glycosylation take place?

A

ER

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

N-linked glycosylation

A

Occurs on asparagine residues - addition of oligosaccharide to asparagine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Purpose of glycosylation

A

Makes proteins more hydrophilic and stops aggregation to help folding
Protects from degradation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Function of the rough ER in 6 points

A 
Site for membrane and secretory protein synthesis
Folds proteins in lumen 
Glycosylates proteins
Makes disulphide bridges
Checks quality of proteins
Calcium store
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe the smooth ER

A

Connected to rough ER
Exit sites for transport vesicles
Synthesise lipids and steroids
Abundant in cells that metabolise ipisd

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Orientation of the golgi apparatus

A

Cis faces towards the nucleus and trans faces the plasma membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In the golgi apparatus where does the direction of secretion run from

A

Cis to trans

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe the golgi apparatus

A

Flat sac like cisterna
Distinct compartments with different enzymes in each stage
Cis faces the nucleus - incoming site
Trans faces the plasma membrane - outgoing site
Movement in a cis to trans direction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens in each golgi stack?

A

There is further glycosylation that leads to complex specific polysaccharide modifications

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the multiple routes of vesicle traffic in the golgi apparatus?

A

Forward traffic: ER to golgi to plasma
Reterograde transport: gogi to golgi to ER. retrieval of resident proteins
Endocytosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the two models of progression through the golgi apparatus?

A

Vesicle transport model

Cisternal maturation model

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Vesicle transport model

A

Each cisterna remains in one place with unchanging enzymes so the proteins move through the sacks using vesicles to transport them to each stack.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Cisternal maturation model

A

New cis cisterna form and transverse through the golgi stack. Changes accunulate as enzymes from earlier cisternae move into the stack. Reterograde traffic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is endocytosis

A 
The internalisation of the plasma membrane:
used to internalise nutrients
Controls cell surface proteins 
Clathrin mediated by endocytosis 
Mediated by Clarthrin and adaptors
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What areas is the golgi apparatus made up of?

A

cis
medial
trans

17
Q

Give an overview movement of proteins through the golgi

A

Proteins in the lumen of the ER are packaged into vesicles and bud from the ER. These vesicles fuse to form new cis-golgi cisternae and the entire vesicle will move in the cis-trans direction by cisternal maturation. Retrograde transport vesicles move proteins to the proper compartments. Protein maturation occurs in the trans network and the vesicle buds off to be exocytosed

18
Q

Lysosome destined membrane proteins

A

Transported in vesicles to the late endosome as the vesicles begin to fuse, then to the lysosome.

19
Q

Endocytic pathway for internalising low desity lipoprotien

A

A cell surface LDL receptor binds to an ApoB protein on the LDL particle. A complex incorporates the particle into the cell forming an endocytic vesicle.
Clathrin coared pits are pinched off by a dynamin-mediated mechanism. The vesicle is clathrin coated.
The vesicle coat is shed to form the early endosome which is an uncoated eukaryotic vesicle. The early endosome fuses with a late endosome. The LDL particle is released from the LDL receptor. The late endosome fuses with a lysosome. Remaining components are recycled

20
Q

What drives membrane curvature?

A

Clathrin cage assembly

21
Q

What is a clathrin cage formed from?

A

Multiple hexomeric complexes called triskelion

22
Q

How does clathrin attach to a membrane?

A

Through an adaptor protein

23
Q

Outline the steps involved for clathrin to assemble on a membrane

A

Ligand binds to a transmembrane protein receptor which induced a conformational change so adaptor proteins are recruited. Clathrin proteins then assemble and link together. Once one Clathrin molecule is bound they accumulate

24
Q

How are endocytic vesicles released?

A

Dynamin- pinching off of the bud. Dynamin forms a collar and squeezing/stretching brings the membrane together to fuse.

25
Q

COPII

A

The Cis - golgi network if formed by the fusion of COPII vesicles from the ER

26
Q

COPI

A

The Cis-golgi is formed when COPI vesicles containing enzymes from the cis-golgi stack fuse with the cis-golgi network

27
Q

How is the medial golgi formed?

A

When COPI vesicles containing enzymes from medial-golgi stack fuse with cis-golgi network

28
Q

How is the trans-golgi formed?

A

When COPI vesicles containing enzymes from Trans-golgi stack fuse with the medial golgi network.

29
Q 
COPII
COPI
COPI
Clathrin
Clathrin
A 
ER -> GOLGI
GOLGI -> ER
GOLGI -> GOLGI
GOLGI -> ENDOSOME
PLASMA MEMBRANE -> ENDOSOME
30
Q

What are COP proteins?

A

Protein complex that coat vesicles transporting proteins from the cis end of the golgi back to the RER.

31
Q

What does COPII drive?

A

ER - ER - Golgi vesicle formation which is forward transport

32
Q

What does COPI drive?

A

Golgi - ER which is retrograde transport used in cisternal progression.

33
Q

What would happen without backward transport?

A

ER would eventually disappear so there is recycling of plasma membrane.

34
Q

Donor compartments

A

donate V-snares

35
Q

V-SNARES & T-SNARES

A 
V-SNARE = Vesicle SNARE
T-SNARE = Target SNARE

V-SNARES & T-SNARES role in targeting correct compartment fusion.

36
Q

SNARES are unstructured until…

A

They bind each other to form a 4 helix bundle which brings to membranes into close proximity resulting in fusion

37
Q

Do T and V SNARES bind each other?

A

Yes

38
Q

What is an advantage of SNARES forming a tight complex?

A

Water molecules are excluded from the space so the membrane is pulled to close proximity. Excluding water allows fusion.
Stalk -> Hemifusion -> Fusion

39
Q

What does SNARE mediated fusion work through?

A

Hemi-fused intermediate where one SNARE complex causes fusion of one leaflet and two SNARE complexes are needed for complete fusion.

Molecules and cells - M.G (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions