Cells have external and internal

1
Lecture 10 - Membranes
Cells have external and internal membranes
2
Adjacent cells are separated by a fluid filled
space
Intercellular fluid space
Cell 2
Cell membrane
Cell 1
Cell membrane
3
Hydrophilic head
Constant motion
Hydrophobic tails
Phospholipids
4
Air
Hydrophobic tail
Hydrophilic head
Water
5
Hydrophilic
Hydrophobic
Phospholipid bilayer
Hydrophobic
Hydrophilic
6
The lipid bilayer is called fluid because the
phospholipds are in continuous motion laterally

Lateral movement only
Time
Fig. 5.04
7
Cell watery environment
oily membrane
External watery environment
8
Water
Phospholipid Bi-layer
Water
liposome
9
Liposome delivers anticancer drug to tumor
Ovarian tumor
10
Phospholipid bi-layers have proteins
11
Extracellular fluid
Phospholipid tails
Make him STOP!!
Cytosol
Proteins
Fig. 5.07a
12
Phospholipid bi-layers have cholesterol
13
Glycoprotein protein carbohydrate
14
HIV
Glycoproteins 1. HIV match up with human
cells 2. Communication between cells
15
Binding of HIV glycoproteins and proteins of cell
16
100,000,000,000 cells at birth
Glycoproteins establish brain cell connections
Every cell connected to 10,000 other
cells 1015connections at birth 10,000,000,000,000,
000 (quadrillion)
17
Movement of molecules and ions in and out of cells
18
Brownian Motion Random motion of ions,
atoms, molecules due to their kinetic (motion)
energy.
19
Brownian motion results in molecules becoming
evenly spread out
20
Dust
Air molecules keep dust suspended because air
molecules are in constant motion (Brownian motion)
21
Diffusion Defined Movement of substance from
a region of higher concentration of substance to
region of lower concentration of same substance.
22
Diffusion
23
A couple of drops of dye
Diffusion begins
Dye is evenly distributed
24
Osmosis defined
Diffusion of solvent (water) across a permeable
membrane.
25
Membrane
Osmosis
26
Kidney receives 20 of blood flow and cleans
blood by osmosis and diffusion
27
Kidney machine performs blood cleansing by
diffusion of waste and toxins
28
Hypotonic (outside of cell)
10 solute 90 water
outside cell
Goes in fast
Goes out slow
30 solute 70 water
Hypotonic Cell fills up with water
Inside cell
29
Hypertonic (outside of cell)
30 solute 70 water
outside cell
Goes in slow
Hypertonic Cell loses water and shrinks
(plasmolysis)
10 solute 90 water
Inside cell
Goes out fast
30
Isotonic (outside of cell)
30 solute 70 water
outside cell
Isotonic Cell gains and loses equal water
stays same size
30 solute 70 water
Inside cell
31
(No Transcript)
32
Hypertonic
Hypotonic
Isotonic
33
Plasmolysis cell shrinkage
Cell Wall
Plasma membrane shrinks away from cell wall when
cell loses water.
34
Facilitated Diffusion Diffusion of ions or
molecules across membrane using membrane carrier
protein
35
Membrane Protein
Facilitated Diffusion
http//bio.winona.msus.edu/berg/ANIMTNS/FacDiff.ht
m
36
Active Transport Transport of substance across a
membrane against diffusion using ATP and membrane
protein
37
Molecule or ion
ATP energy
ATP
ATP
ATP
ATP
ATP
ATP
ACTIVE TRANSPORT
Membrane protein
38
(No Transcript)
39
Cocaine blocks reuptake of dopamine

Vesicle from Golgi with dopamine
Neuron 2
Neuron 1
diffusion
Active transport
Dopamine (protein) receptor
Dopamine

Dopamine (protein) receptor
40
Cocaine dopamine stimulant blocks
reuptake of dopamine and leaves it synaptic cleft
longer

Vesicle from Golgi with dopamine
Neuron 1
Neuron 2
diffusion
Active transport
Dopamine (protein) receptor
Dopamine

Dopamine (protein) receptor