4. Cytoskeleton
• Made of long, thin,
protein filaments.
– Three sizes
• Microfilaments
• Intermediate filaments
• Microtubules
• Provides internal cell
structure.
• Anchor and connect
organelles.
• Move parts and products.
8. Plasma Membrane
• Proteins act as
channels,
recognition
molecules,
carrier proteins,
etc.
• Carbohydrates
help connect
cells and play a
role in
identification.
11. Osmosis
• Type of diffusion.
• Movement of water across semipermeable membrane from
area of high water concentration to area of low water
concentration.
12. Effect of osmosis on cells in
various solutions
• Hypotonic solutions
– High concentration of
water in extracellular
fluid compared to
inside the cells
causes net movement
of water into the cell.
– Results in increased
cell size.
– Can cause cell to
burst.
13. Effect of osmosis on cells in
various solutions
• Isotonic solutions
– Concentrations of
water inside and
outside of the cell
are equal.
– Results in no net
movement of
water.
– Cell size remains
the same.
14. Effect of osmosis on cells in
various solutions
• Hypertonic
solutions
– Concentration of
water in cell
exceeds that
outside of cell.
– Results in net
movement of water
out of the cell.
– Cell shrinks.
15. Membrane transport
• Large or hydrophilic
substance cannot pass
freely through the
membrane.
• To move them through
the membrane, must
have channel proteins or
carrier proteins.
16. Passive Transport: Ion Channels
• Ions are hydrophilic and the channel must be
open for the ion to pass through the channel.
• Selective for each ion.
• Ion moves down concentration gradient.
