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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
Q 
Explain these structures
Sphingosine 
A ceramide
A sphingomyelin x2
A cerebroside 
A ganglioside
A

Slide

26
Q

What is a glycerol based lipid called ?

A

Glycolipids

27
Q

How are glycolipids formed ?

A

Carbohydrate head group instead of phosphate

28
Q

What is a Sphingosine-based lipid called ?

A

Sphingolipid

29
Q

What is a Combination of glycerol and sphingosine-based lipid called ?

A

Glycosphingolipids

30
Q

Name the two most common Glycosphingolipids?

A

cerebrosides and gangliosides

31
Q

What % of the plasma membrane are glycolipids ?

A

5-10%

32
Q

What is the structure of a glycolipid ?

A

Carbohydrate head group
Lipid backbone-(Glycerol or sphinogosine based)
Fatty acid tails

33
Q

Explain the structure of the antigen(s) associated with the the blood group O?

A

Galactose + N acetyl-glucosamine + galactose +fucose

34
Q

Explain the structure of the antigen(s) associated with the the blood group B?

A

Galactose + N acetyl-glucosamine + galactose bound to both fucose + galactose

35
Q

Explain the structure of the antigen(s) associated with the the blood group A?

A

Galactose + N acetyl-glucosamine + galactose bound to both fucose + N acetyl-galactosamine

36
Q

Explain the structure of the antigen(s) associated with the the blood group AB ?

A

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
Q

How does a sterol effect the properties of the plasma membrane ?

A

Fluidity (depends on temp/conc)
Permeability (up)
Stability & integrity (maintains)

38
Q

Describe a sterol based lipid ?

A

Hydrophilic head

Steroid ring

39
Q

What are the three eats phospholipids can’t move in the plasma Membrane

A

Rotation

Lateral diffusion- switched places with a neibouring lipid

Transverse diffusion- switched places with a lipid from the other monolayer
Aka flip flop

40
Q

How does temp effect the fluidity of the plasma membrane ?

+ draw

A

Postive correlations
Slow increases
Then steep
Then shallow again

41
Q

How does cholester effect the fluidity of the plasma Membrane ?
Why ?

A

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
Q

How does the length of the phospholipid effect the fluidity of the membrane ?

A

Shorter chain lengths reduces fluidity

43
Q

How do cis double bonds effect the fluidity in the pm?

A

Produces kinks in the fatty acids , reducing packing. Increasing fluidity

44
Q

Why are Polyunsaturated Fatty Acids considered to be good for your health?

A

These take up hydrogens in our body while using energy

Lowers bad cholesterol LDL

45
Q

How does the conc of cholesterol effect mortality ?

A

Higher cholesterol higher likely hood of
Cardiovascular death

However very low cholesterol may also cause death

46
Q

What % of the plasma membrane are membrane proteins ?

A

20-60%

47
Q

What are the three classes of membrane proteins ?

+ explain

A

Integral - hydrophobic inside hydrophilic outside of membrane
Peripheral - attached through ionic interactions
Lipid anchored -attached to glycolipid

48
Q

What is a lipid raft ?

Function

A

A cluster of lipid and proteins within a membrane. That is cholesterol rich

Signalling

49
Q

How do lipid rafts effect fluidity of the plasma membrane?

A

Decrease

50
Q

Name 6 functions of a cell membrane

A 
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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