90 likes | 311 Views
Cell transport. Active Transport and Bulk Transport. Cellular Energy. Many cell processes require energy Cells use energy in the form of ATP Adenosine Triphosphate When ATP reacts with certain compounds in the cell it breaks down into Adenosine diphosphate (ADP) and releases energy.
E N D
Cell transport Active Transport and Bulk Transport
Cellular Energy • Many cell processes require energy • Cells use energy in the form of ATP • Adenosine Triphosphate • When ATP reacts with certain compounds in the cell it breaks down into Adenosine diphosphate (ADP) and releases energy. • ATP ADP + phosphate + energy
Active Transport • Movement through the cell membrane through carrier proteins • carrier proteins in the cell membrane bind with the molecule to be transported • chemical energy (ATP) allows the carrier to change shape so the molecule gets transported along to the inside of the membrane where it is released. • Against a concentration gradient • From low solute concentration to high solute concentration • Sodium-Potassium Pump • Maintains function of nerve and muscle cells • Pumps sodium and potassium ions in and out of cell
Endocytosis • Bulk transport of materials into the cell • Substances that are too large to pass through the cell membrane • Cell forms a pocket or infolding of the membrane which transports the needed substance into the cell • Two types of endocytosis • pinocytosis • phagocytosis
Endocytosis - Phagocytosis • “Cell eating” • transport of solids into the cell in large vesicles. • white blood cells protect us from disease by phagocytizing bacteria • http://www.youtube.com/watch?v=JnlULOjUhSQ&feature=related
Endocytosis - Pinocytosis • “Cell Drinking” • the process of engulfing liquid food material • the membrane-bound vesicle is called a pinocytotic vesicle • they are very small and can only be seen with an electron microscope
Exocytosis • the reverse process of endocytosis • expulsion or secretion of materials from the cell • Used to • expel wastes such as indigestible particles • secrete substances like large protein molecules, such as hormones
Critical Thinking Questions What would happen to the size of the cell membrane if a cell were to undergo a lot of endocytosis and no exocytosis? Why do grocery stores spray fruit and vegetables with water in an attempt to keep them fresh? Study Suggestion Make a concept map to show all the methods of transport through the cell membrane. Consider how transport of materials allows cells to maintain homeostasis.