1. 1.16 Active Transport and Bulk Transport

2. Energy, Cells, and ATP
ATP – adenosine triphosphate; a compound used as a source of energy in cells
When ATP releases a phosphate, energy is produced

3. Active Transport
Active Transport – the movement of substances through a membrane against a concentration gradient using carrier proteins and ATP
Against the concentration gradient means that it moves from an area of [low] to [high]

4. Sodium-potassium pump – an active transport mechanism that pumps Na+ and K+ ions into and out of a cell
Without this pump, your nerve and muscle cells won’t function properly
Pumps require ATP to operate

6. Bulk Transport
The movement of large quantities of materials into or out of the cell

7. Endocytosis
Brings large amounts of material into the cell from the extracellular fluid

8. There are two forms of endocytosis:
1. Phagocytosis – bulk transport of solids into the cell
The cell membrane sends out finger-like projections called pseudopods that surround and enclose the particle in a vesicle that is within the cell’s cytoplasm
Such a vesicle is called a phagocytotic vesicle
Macrophages use this to engulf harmful bacteria
2. Pinocytosis – bulk transport of liquids into the cell
Pinocytotic vesicle – a vesicle that is formed when cells engulf extracellular fluid by pinocytosis

9. Exocytosis
The movement of large amounts of material out of a cell by secretory vesicles
Secretory vesicles – the membrane sac containing substances that are transported out of a cell
The secretory vesicle fuses with the cell membrane and spills its contents into the extracellular fluid
Proteins produced in the rough endoplasmic reticulum are packaged into secretory vesicles by the Golgi apparatus and are transported out of the cell by exocytosis

12. Homwork
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