Download Cell Transport

Topic:
Cell Transport
Questions/Main Ideas:
Name: ____________________________
Date:_________________________
How do substances get into and out of cells?
How do cells get what they need and get rid of what they need to get rid of?
Objective: - We will be able to describe the different processes that allow movement
across the cell membrane, including: diffusion, osmosis, and active transport.
Cell membranes are selectively permeable:
- Some small substances can pass freely
- Other molecules have to go through protein channels
2 Types of transport across membranes
1. Passive transport = Does not require energy to move particles
2. Active Transport = Requires energy to move particles
- Energy is needed because the traveling molecules are traveling against the
concentration gradient = going from a low concentration area of that
molecule to a higher concentration area (it’s like walking into a crowded
room or biking uphill)
Passive Transport – net movement from an area of high concentration to a lower
concentration area :
- Diffusion = movement of molecules (solutes) across a membrane
- Osmosis = diffusion of water molecules across semipermeable membrane
- Facilitated Diffusion = movement of larger substances by use of a carrier
protein
Active Transport – requires energy to move from low concentration to high
- Pumps = protein channels that use energy to move molecules
- Endocytosis = cell engulfs material by moving the cell membrane around
the material– makes a pouch (vesicle) around material to take into the cell
- Exocytosis = cell expels (releases) material by connecting the membrane
(vesicle) around the material to the cell’s membrane
Summary:
How does cell transport maintain homeostasis?
Topic:
Tonicity
Questions/Main Ideas:
Name: ____________________________
Date:_________________________
How does the selective permeability of the cell membrane affect the life of a cell in
different environments?
Review of Solutions
• Solutions- mixture of a solute and a solvent
• Solvent - the liquid into which the solute is dissolved. Ex) water
• Solute - substance that is dissolved. Ex) Salt
Semipermeable = permeable to some substances = SOME substances can
freely pass into and out of the cell.
If some substances cannot easily pass, then the solution inside of a cell can
be different from the solution outside of the cell.
The life/health of the cell can be affected if the cell cannot transport these
substances (solutes).
Isotonic solution = solution inside and outside have the
same concentrations of solute
- If a cell is in an isotonic solution, water diffuses
equally into and out of the cell
o This makes a happy cell
Hypotonic solution = this solution has a lower
concentration of solutes than the other
- If a cell is in a hypotonic solution, water will
diffuse into the cell
o This can cause a cell to swell and burst
Hypertonic solution = this solution has a higher
concentration of solute than the other
- If a cell is in a hypertonic solution, water will
diffuse out of the cell
o This can cause a cell to shrivel up
Summary: