Download Cell transport PPT - Effingham County Schools

Cellular Transport
Yeast cells stained
with fluorescent dye
The cell membrane
The Cell Membrane
• Selectively permeable (semi-permeable)
allows only certain substances to pass through
cannot control the movement of water
Cell membrane
The fluid mosaic model
• double layer of lipids with proteins
scattered throughout
• flexible, phospholipids move with in the
membrane
Parts of the cell membrane
• Phospholipids
– lipids with a
phosphate group
attached to one end
– makes molecule
polar so it can react
with water
Parts of the Cell Membrane
• Transport Proteins- allows needed substances
or waste materials through membrane
Parts of the Cell Membrane
• Cholesterol
– stabilizes the phospholipids
– does not allow fatty acid chains to stick
together
cholesterol
Type of Cell Transport
•
•
•
•
•
Simple diffusion
Osmosis
Facilitated diffusion
Active transport
Endocytosis/Exocytosis
Diffusion
• Particles move from an area of high
concentration to an area of low concentration
• Moves “down” or “with” the concentration
gradient
• Does not require energy
Diffusion
• Factors effecting the rate of diffusion
1. temperature (as temp increases rate increases)
2. pressure (as pressure increases rate increases)
3. steepness of the concentration gradient (the
steeper the gradient the faster the diffusion)
Osmosis
• Movement of WATER across a cell
membrane
• Cell has no control
• continues to move until [inside] = [outside]
called dynamic equilibrium
• [ ]- means “the concentration of”
Types of Solutions
• Isotonic
• Hypotonic
• Hypertonic
Types of Solutions
• Isotonic – [water inside] = [water outside]
• Hypotonic – [water inside] < [water outside]
– solutes are higher inside the cell
– water flows in, cell swells
– cell could burst if continues
• Hypertonic – [water inside] > [water outside]
– solutes are higher outside the cell
– water leaves cell, cell shrinks
Types of Solutions
Isotonic
Hypotonic
Water particle
Solute particle
Hypertonic
Types of Solutions
• Water always moves
toward the solution with
the highest concentration
of solute
Type of Solutions
Notice water
level rises on
side of
membrane
with the
highest solute
concentration
Types of Solutions
Effects on Animal Cells
The pictures below are red blood cells in different concentrations
of salt solution. Identify which pictures are hypotonic, isotonic,
and hypertonic solutions.
Isotonic
Hypertonic
Hypotonic
Types of Solutions
Effects on Plant Cells
Which of these cells are in a hypotonic
solution? Hypertonic solution?
Hypotonic
Hypertonic
Facilitated Diffusion
• moves down the concentration gradient with aid of
protein
• Does not use energy
• most glucose moved this way
Passive Transport
• NO energy required
• Diffusion, Osmosis, and Facilitated
Diffusion are all forms of passive transport
Active Transport
• Requires energy
• moves from an area of low concentration to
an area of high concentration
• moves “up” or “against” the concentration
gradient
• glucose moved from blood stream into liver
for storage
Active Transport
Moving large particles across the
cell membrane
• Endocytosis – movement of large particles into the cell
• Exocytosis – movement of large particles out of the cell
Endocytosis
Exocytosis