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IMS > W1- Lecture 2- Plasma Membrane > Flashcards

W1- Lecture 2- Plasma Membrane Flashcards

1
Q

Plasma Membrane Functions

A

Barrier
Transport of ions, nutrients and other small molecules
Cell-cell interactions, cell signalling (receptors)

Sites of metabolic activities
Cell shape

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2
Q

What model is used to describe the plasma membrane ?

A

Fluid mosaic model

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3
Q

Why does the electron microscope have i higher resolution then a light microscope ?

A

Smaller wavelength can see smaller structures

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4
Q

What happens to a cell in a

  1. hypotonic solution
  2. hypertonic solution
A
  1. Swell

2. shrink

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5
Q

Evidence for the existence of plasma membrane (3)

A

1) Cell swelling [hypotonic] & shrink [hypertonic]
2) Escape of cell contents if mechanically ruptured

3) Compartmentalization needed for biochemical activity of cells
E.g ph diff

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6
Q

Review the timeline of the development of fluid mosaic model

A 
The membrane is lipid 
Lipid monolayer 
Bi layer 
Bi layer + protein sheet 
Unit membrane (e- microscope )
Fluid mosaic model 
Membrane protein structures
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7
Q

The invention of the election microscope helped revealed the structure of the plasma membrane
Through what two techniques

A

Osmium staining (stains pm)

Freeze fracture
-can see proteins throughout the membrane

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8
Q

Define amphiphilic

A

Both hydrophilic & hydrophobic regions

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9
Q

What % of the membrane are lipids

A

30-80

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10
Q

Name three types of membrane lipids

A

Phospholipids
Glycolipids
Sterols

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11
Q

Describe the structure of a phospholipid

A

Hydrophilic head

Two hydrocarbon hydrophobic tails

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12
Q

Describe the structure of a glycolipid

A

S

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13
Q

Describe the structure of a sterol

A

.

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14
Q

What the length of a phospholipid tail ?

A

14-24

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15
Q

What does a cis- double bond in a phospholipid tail cause ?

A

DUL

Creates a kink and the phospholipid fills more

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16
Q

What are the two aggregation styles ?

A

Cone shaped - lipid molecule -single chain (micelles )

Cylinder shaped - phospholipids - double tailed (bilayer)

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17
Q

What a glycerol based phospholipid called ?

A

phosphoglyceride

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18
Q

Name the 4 main phosphoglycerides in the plasma membrane

A

Phosphatidylcholine
Phosphatidylethanolamine
Phosphatidylserine (-)
Phosphatidylinositol

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19
Q

Structure of glycerol

A

H2COHCHOHCH2OH

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20
Q

What bond is formed between a fatty acid and a glycerol ?

A

Ester bond

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21
Q

Name 6 common phospholipid head groups

A 
Choline 
Ethanolamine 
Serine 
Glycerol 
Glycerol(2)
Mayo-inositol
22
Q

Draw a ____ phospholipid head Group

Choline 
Ethanolamine 
Serine 
Glycerol 
Glycerol(2)
Mayo-inositol
A

Look on presentation

23
Q

Describe a phospholipid structure

A

Polar head (usually: choline, ethanolamine, serine, inositol)

Glycerol or sphingosine

Lipid tail(s)

24
Q

Name 5 sphingosine based membrane lipids

A 
Sphingosine 
A ceramide
A sphingomyelin
A cerebroside 
A ganglioside
25
``` Explain these structures Sphingosine A ceramide A sphingomyelin x2 A cerebroside A ganglioside ```
Slide
26
What is a glycerol based lipid called ?
Glycolipids
27
How are glycolipids formed ?
Carbohydrate head group instead of phosphate
28
What is a Sphingosine-based lipid called ?
Sphingolipid
29
What is a Combination of glycerol and sphingosine-based lipid called ?
Glycosphingolipids
30
Name the two most common Glycosphingolipids?
cerebrosides and gangliosides
31
What % of the plasma membrane are glycolipids ?
5-10%
32
What is the structure of a glycolipid ?
Carbohydrate head group Lipid backbone-(Glycerol or sphinogosine based) Fatty acid tails
33
Explain the structure of the antigen(s) associated with the the blood group O?
Galactose + N acetyl-glucosamine + galactose +fucose
34
Explain the structure of the antigen(s) associated with the the blood group B?
Galactose + N acetyl-glucosamine + galactose bound to both fucose + galactose
35
Explain the structure of the antigen(s) associated with the the blood group A?
Galactose + N acetyl-glucosamine + galactose bound to both fucose + N acetyl-galactosamine
36
Explain the structure of the antigen(s) associated with the the blood group AB ?
2 different antigens A Galactose + N acetyl-glucosamine + galactose bound to both fucose + N acetyl-galactosamine B Galactose + N acetyl-glucosamine + galactose bound to both fucose + galactose
37
How does a sterol effect the properties of the plasma membrane ?
Fluidity (depends on temp/conc) Permeability (up) Stability & integrity (maintains)
38
Describe a sterol based lipid ?
Hydrophilic head Steroid ring
39
What are the three eats phospholipids can’t move in the plasma Membrane
Rotation Lateral diffusion- switched places with a neibouring lipid Transverse diffusion- switched places with a lipid from the other monolayer Aka flip flop
40
How does temp effect the fluidity of the plasma membrane ? | + draw
Postive correlations Slow increases Then steep Then shallow again
41
How does cholester effect the fluidity of the plasma Membrane ? Why ?
Cholester buffers the fluidity change Initially more fluid- cholesterol reduces packing hence more room to move Then it reduces fluidity - less effected by temp Too much cholesterol decrease fluidity
42
How does the length of the phospholipid effect the fluidity of the membrane ?
Shorter chain lengths reduces fluidity
43
How do cis double bonds effect the fluidity in the pm?
Produces kinks in the fatty acids , reducing packing. Increasing fluidity
44
Why are Polyunsaturated Fatty Acids considered to be good for your health?
These take up hydrogens in our body while using energy Lowers bad cholesterol LDL
45
How does the conc of cholesterol effect mortality ?
Higher cholesterol higher likely hood of Cardiovascular death However very low cholesterol may also cause death
46
What % of the plasma membrane are membrane proteins ?
20-60%
47
What are the three classes of membrane proteins ? | + explain
Integral - hydrophobic inside hydrophilic outside of membrane Peripheral - attached through ionic interactions Lipid anchored -attached to glycolipid
48
What is a lipid raft ? Function
A cluster of lipid and proteins within a membrane. That is cholesterol rich Signalling
49
How do lipid rafts effect fluidity of the plasma membrane?
Decrease
50
Name 6 functions of a cell membrane
``` 1boundry and permeability membrane 2or ganiation of eukaryotic organelles fort functions 3transport processes 4signallinh 5cell to cell interactions 6reaction takes place here e.g enzymes ```

IMS (74 decks)

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