Osmosis and active transport allow movement of water and solutes across cell membranes. Osmosis occurs when water moves from areas of higher water concentration to lower across semi-permeable membranes. Active transport uses ion pumps and cotransport to move solutes against gradients. Cells use ATP as an energy source, breaking it down into ADP, to power active transport and other processes like endocytosis which involves the uptake of particles and liquids into cells through phagocytosis, pinocytosis, and receptor mediated endocytosis.

1. Biology and Human Concerns
Notes – 10/07/09
Osmosis in Animal Cells
Osmosis Terms:
Hypotonic solution is the solution that looses the water
Hypertonic solution is the solution that gains the water
Isotonic solutions: have the same water concentration
-Find out what has highest water concentration (lower in solutes)
-Find out which way the water is going to move
Active Transport
-Some ion pumps generate voltages across membranes
-In cotransport, a membrane protein couples the transport of one solute to
another.
ATP / ADP
-Adenine triphosphate / Adenosine diphosphate
Loss of phosphate in ATP results in ADP – cell energy.
Endocytosis:
Phagocytosis
-Destruction of solid “food” particle
Pinocytosis
-Destruction of liquid “food” particle
Receptor Mediated Endocytosis
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