Download Academic Cell Boundary PPT

Cell Boundaries/ Cell Membrane
Animal cell
Plant cell
Cell / Plasma
Membrane
Cell Wall –
provides
support &
protection,
usually made
of tough
fibers
1. The Cell Membrane


Complex barrier separating the cell from it's external
environment
– Holding cytoplasm within cells
– Regulating substances entering and exiting cells
– Recognizing other cells
Is arranged in a double layer
called a Lipid Bilayer –
Made up of Phospholipids
(a phosphate group
& 2 fatty acids)
1. The Cell Membrane

"Selectively Permeable" membrane that regulates
(like a gate) what passes into and out of the cell
1. The Cell Membrane


Cell Membranes are FLUID
Lipids and Proteins of the Cell Membrane are
always in motion
1. The Cell Membrane

Membrane Proteins
– PROTEIN MOLECULES are EMBEDDED in
the Lipid Bilayer
– HELP to MOVE Material INTO and OUT of
the Cell
1. The Cell Membrane
–
Often have carbohydrates attached to them to
serve as I.D. badges that allow cells to recognize
each other
1. The Cell Membrane

Diffusion
– Movement of particles from an area of high
concentration to an area of low concentration
(no energy required) (put dye in water)

Osmosis
– Diffusion of water through a selectively
permeable membrane
1. The Cell Membrane

Facilitated Diffusion / Passive Transport
– Uses proteins to move molecules through a
cell membrane along the concentration
gradient (no energy required)
1. The Cell Membrane

Active Transport
– Uses proteins to move molecule against the
concentration gradient
– Requires energy
Exocytosis and Endocytosis


Exocytosis – process of a cell releasing materials
(exiting)
Endocytosis – process of cell taking materials in
(entering)
Exocytosis
Example of both:
Neurotransmitter
• Exocytosis and
Endocytosis Example
• Neurotransmitter
• Osmosis Examples
• Hypotonic-Isotonic-Hypertonic
(Fold a piece of paper in half)



Isotonic
– The concentration of solutes is the same inside and
outside the cell
– Water moves in and out
Hypertonic
– Solution has a higher solute concentration than the cell
– Water moves out
Hypotonic
– Solution has a lower solute concentration than the cell
– Water moves in
Draw this on a
Youtube

http://www.youtube.com/watch?v=HqKlLm2MjkI
Which cell process will move
substances against a concentration
gradient?
[NC08 EOC]
A
B
C
D
E
diffusion
facilitated diffusion
osmosis
passive transport
Requires ENERGY
active transport
Which diagram represents
active transport?
[TN09 EOC]