- Active transport methods move molecules in the direction of the higher concentration
and require energy and a carrier protein. - Vesicles can be used to move large molecules, which requires energy input.
Review Questions
- What happens when a cell is placed in a hypotonic solution?
- What happens when a cell is placed in a hypertonic solution?
- What’s the main difference between active and passive transport?
- List an example of active transport.
- List the types of passive transport.
- Why is the plasma membrane considered semipermeable?
- What is the process where a cell engulfs a macromolecule, forming a vesicle?
- What is diffusion?
- Explain the results of a sodium-potassium pump working across a membrane.
- Does facilitated transport move a substance down or up a gradient?
Further Reading / Supplemental Links
- http://www.vivo.colostate.edu/hbooks/cmb/cells/pmemb/passive.html
- http://www.vivo.colostate.edu/hbooks/molecules/sodium_pump.html
- http://www.biologycorner.com/bio1/diffusion.html
- http://www.northland.cc.mn.us/biology/Biology1111/animations/transport1.
html - http://www.brookscole.com/chemistry_d/templates/studentresources/shared
resources/animations/ion_pump/ionpump.html - http://www.enwikipedia.org/
Vocabulary
active transport Moving a molecule from an area of lower concentration to an area of
higher concentration; requires a carrier protein and energy.
concentration The amount of a substance in relation to the volume.
diffusion Movement of molecules from an area of high concentration to an area of low
concentration; requires no energy.
endocytosis Movement of substances into the cell by vesicle formation.