Cellular Transport

1
Cellular Transport
2
The Plasma Membrane
A. Structure Fluid Mosaic Model
                           Phospholipid bi- layer
                            1.    Hydrophilic Head
a.     Polar head
b.     Faces out, in outer layer
c.     Faces in, in inner layer
d.     Water loving
3
2.    Hydrophobic Tails
a.     Face each other
b.     Non-polar
c.     Water fearing
4
Proteins (Fibrous)
Carbohydrates
Globular Proteins
Cholesterol molecules
5
Blue dots H2O molecules
Brown Squares NaCl molecules
6
(No Transcript)
7
(No Transcript)
8
Diffusion
movement of molecules from a higher concentration
to a lower concentration or those molecules
9
Passive Transport
10
Osmosis
Diffusion of water across a selectively permeable
membrane.
Two types of pressure involved in osmosis
Osmotic pressure
Turgor pressure
11
Tonicity Strength of a solution
1. Isotonic
There is a net movement of molecules of
water into and out of the cells, so no change in
shape in noted.
The concentration of dissolved substances in
equal in and out
12
2. Hypotonic Solution
The concentration of dissolved substances
outside the cell are greater than inside the
cell, thus there is fewer water molecules outside
the cell than inside, so water must move out to
balance the concentration of water.
13
3. Hypertonic Solution
The concentration of dissolved substances
outside the cell are fewer than inside the cell,
thus there is fewer water molecules inside the
cell than outside, so water must move in to
balance the concentration of water.
14
Transport By Carrier Proteins
Carrier Proteins Proteins imbedded in the
plasma membrane that change shape to allow the
passage of certain substances through the plasma
membrane.
Channel Proteins Proteins imbedded in the
plasma membrane that allow only specific
molecules to flow unabated through the membrane.
Facilitated Transport (help) passage of
molecules across the plasma membrane, by either
carrier proteins or through channel proteins,
even though they are not lipid soluble.
Direction of travel of molecules is with the
concentration gradient, so no energy input is
required.
Active Transport Substances are moved against
their gradient by carrier proteins.
(Na K pump) carrier molecule
15
Channel Proteins
Proteins imbedded in the plasma membrane that
allow only specific molecules to flow unabated
through the membrane.
16
Cytosis
17
Endocytosis
Here we see a leukocyte (white blood cell)
engulfing a bacterium by encroaching on the
bacterium with pseudopodic extensions from its
cytoplasm. The membrane will close around the
bacterium until the bacterial cell is inside the
leukocyte, where is will be digested.
Phagocytosis
18
Phagocytosis
Here we see an Amoeba engulfing a Paramecium
through the process of Phagocytosis, a type of
endocytosis.
19
Here we see a phagocyte, a type of white blood
cell, engulfing a Bacterium through the process
of Phagocytosis, a type of endocytosis.
20
This macrophage is engulfing a bacteria, in a
process known as phagocytosis. The bacteria will
then be destroyed.
21
Exocytosis
Moving molecules out of a cell through the plasma
membrane. This is a type of active transport.
22
Pinocytosis
Moving water out of a cell through the plasma
membrane. This is a type of active transport.
23
The End