Lecture 6 Cell Integrity - By Vladimir Sytnyk

7/18/2019 Lecture 6 Cell Integrity - By Vladimir Sytnyk

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1/5/201

5

Maintaining

Cell

Integri

ty

Dr. Vladimir

Sytnyk

Senior

lecturer,

Head,

Molecular

Neuroiolog

y !aoratory

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cyto%keleton

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Nucleu%

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rotein%,

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(er(i

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!ecture

Membrane

s

Compositio

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Structure

and

Properties

Fluid Mosaic

Model

Fluidity and

Sidedness

Role of Lipids

in Maintaining

Integrity

Role ofProteins in

Maintaining

Integrity

Membrane

permeability

Memr

ane

Model%

phospholipid

bilayer with



hydrophobic

zone

different

organisation

of membrane

proteins

Fluid Mosaic

Model

Davson-

Danielli

Model

(Singer &

Nicholson, 1972)

(1935)



Sidedne%%The plasma

membrane

has distinct

cytoplasmic

and

extracellular

faces.

The

extracellular

face is

topologically

equivalent to

the inside

face of the

ER, Golgi,

lysosome and

vesicle

membranes.

Proteins and

lipids doNOT

easily “flip”

from one side

of the



membrane to

the other.

1



1/5/2015

Memer% o# t"e memrane

Memer% o# t"e memrane

1. Lipids

Hydrophilic

2. Proteins

•

Peripheral



Hydrophobic

•

Integral

Transmembrane:



Proteins that span

Cholesterol

the membrane but

(0 - 25% of total lipid)



have different

domains on each

side of the



membrane

Phospholipids



luid Mo%aic Model

Fluidity refers to the rapid movement of lipids

and proteins laterally, in the plane of the

membrane

hybrid cell

proteins are mixed

mouse

cell

human

after 1 hour

cell



Rapid movement of lipids and proteins laterally, in the plane of

the membrane can also be visualised using microscopy

luore%cent roe

rotein

Source6 Sytnyk7% Molecular Neuroiology !a

Rapid movement of lipids and proteins laterally, in the plane of

the membrane can also be visualised usingFRAP -

fluorescence recovery after photo- bleaching

Integral rotein tagged *it"

- 8 green 9uore%cent rotein

of lipids and laterally, in the

using

-

2



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Lecture 6 Cell Integrity - By Vladimir Sytnyk

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Transcript of Lecture 6 Cell Integrity - By Vladimir Sytnyk