Download The Plasma Membrane

The Plasma Membrane
Pg 101
1. What are the main
characteristics of a eukaryotic cell?
1. What are the main characteristics
of a eukaryotic cell?

NUCLEUS
 Cell Membrane
 Other membrane bound organelles
2. What are common names
for the cell membrane?
2. What are common names
for the cell membrane?

Plasma membrane
 Fluid mosaic model
 Phospholipid bilayer
 Lipid bilayer
 Bilayer
3. What is the function of the
cell membrane?
3. What is the function of the
cell membrane?

Protection
 Selectively Permeable – “picky”
– Allows important nutrients in.
– Gets wastes out.
4. What is the structure of the
cell membrane? – pg 103
4. What is the structure of the
cell membrane?

Lipid Bilayer
 Lipid = fat
 Bi = 2
 Hydrophillic heads
– Water loving

Hydrophobic tails
– Water fearing or hating
4. What is the structure of the
cell membrane?

Integral Proteins –embedded in the membrane
– Allow large molecules such as glucose through the
membrane

Peripheral Proteins – surface proteins both inside
and outside of the cell
4. What is the structure of the
cell membrane?

Glycoproteins – Integral proteins with
carbohydrates attached to the top
– Used for cell recognition
– Hold cells together

Glycolipids – Lipids with carbs attached to the top
– Cell recognition

Cholesterol – Steroid found in the membrane
– Give the cell membrane strength and rigidity.
Summary – bottom of pg 101
Cell Membrane Transport
Pg 105
1. What are the two types of
transport across cell membranes?
Passive
 High concentration  low
concentration
 NO ATP (energy)
Active
 Low concentration  high
concentration
 ATP required
– Simple Diffusion
– Membrane Pumps
– Facilitated Diffusion
– Endocytosis
 Pinocytosos
 phagocytosis
– Osmosis
– Exocytosis
2. Diffusion?

Simple Diffusion – movement of molecules across a
membrane until equilibrium (balance) is reached
– Used for small nonpolar molecules
– Ex: O2
3. Facilitated Diffusion?

Large molecules that can not fit through
the phospholipids – require an integral or
carrier (transport) protein
– Ex: glucose and amino acids
 Each carrier protein is specific for the molecule it
transports
4. Osmosis?

Osmosis – Diffusion of water
– Hypertonic – cell shrinks
 water moves out
 solute concentration greater outside
cell
 (Plasmolysis in plant cells)
– HypOtonic – cell swells and can
burst



water moves in
solute concentration lower outside
cell
(Turgor pressure in plant cells)
– Isotonic – cell stays the same
 water moves in and out
 Solute concentration equal inside and
outside cell
Passive Transport – pg 104

Bubble Map – Top ½ of the page
9. Membrane Pumps?

Uses a carrier protein
and ATP to create a
concentration gradient.
 Sodium – Potassium
Pump
– 3 Na+ out (sodium)
– 2 K+ in (potassium)
10. Endocytosis?
10. Endocytosis?

Used for VERY LARGE molecules and
substances that can not fit through the
membrane
– Pinocytosis – ingestion of fluids
– Phagocytosis – ingestion of large particles of
whole cells

Ex: prokaryotic bacteria that need to be destroyed
11. Exocytosis?
11. Exocytosis?

Release of molecules from the inside of the
cell to the outside.
– Lysosomes release wastes through exocytosis.
– Opposite of endocytosis
HOMEWORK 

Pg 207 # 1 and 2
– Double Column Format

Summary
– Minimum of one sentence per question.