Download Cell Transport Mechanisms

Transport of Materials Through the Cell (Read Chapter 5 in your text)
(pg.8)
1. Homeostasis - a condition of biological balance. Living things have a variety of strategies for
keeping things steady. Ex. Body temperature, heart rate, fluid levels, various hormones.
2. Selectively permeable– This term describes a property of the cell membrane. Only certain
things can come in and out of the cell. The cell maintains homeostasis by being selectively
permeable.
3. Diffusion - the movement of a substance from where there is more of it to where there is less.
Ex. air freshener.
(pgs.97-100)
4. Equilibrium – diffusion of a substance until the concentration is the same throughout a given
space. Ex. a drop of food coloring will make a glass of water the same color throughout.
5. Osmosis - the movement of water across a membrane from where there is more to where
there is less. Ex. vegetables placed in cold water will absorb it, making them crunchy and crisp.
9. Passive Transport - Movement of materials across the cell membrane that requires no energy.
Ex. O2, CO2, H2O
(pg. 103)
10. Active Transport – Movement of materials across the membrane that requires energy to do
so, in the form of ATP. Ex. the sodium potassium pump. (see #12 below)
(pg.101)
11. Facilitated diffusion – a substance moving across the membrane is aided by another
molecule. Ex. sodium ions help glucose pass through the membrane to get to mitochondria.
(pg.104)
12. Na+ / K+ Pump – an exchange of 3 Na+ for 2 K+ across the membrane. Important for nerve
impulses to be received by the cell.
(pg105 -106)
13. Endocytosis – the cell changes its shape to engulf large particles. Ex. white blood cell
eating bacteria
14. Exocytosis – wastes are removed from the inside of the cell by connection a waste vacuole
with the membrane. The membrane then opens and evacuated the wastes.
(pg.57)
15. Enzymes – special proteins that speed up chemical reactions that would otherwise not take
place.