Cell Transport - General Zoology

Transport ProcessesTransport Processes

Ms. Rubie Maranan-Causaren

Passive vs. Active Processes

P iPassive processes

Simple diffusion

Osmosis

Osmosis: film clip

OsmosisOsmosis

Tonicityy

Hypertonic solutionHypotonic solution Isotonic sol’n

0.9% NaCl

Effect of hypertonic solution to plant

cells

Filtration

Facilitated diffusion

Active Processes

Primary Active Transport

Primary Active Transport (continued)

Secondary Active Transport

Secondary active transport. The Na+/K+ pump (a) maintains a concentration of Na+ions that is higher outside the cell than inside. The resulting Na+ gradient providesenergy for secondary active transport pumps. The sodium ions diffuse back into thegy y p p pcell by facilitated diffusion. As these ions diffuse some molecules, like glucose, diffusein the same direction (b); while others, like H+ and Ca2+ , diffuse in oppositedirections.

Bulk TransportBulk Transport

Phagocytosislysosomes

phagocyte bacteria pseudopods fusepseudopod

a. c.b.

h l /di ti l phagosome

f.

degraded bacterium

e.

phagolysosome/digestion vacuole

d.

phagosome

Phagocytosis. (a) A phagocyte approaches particles (e.g. bacterium). Pseudopodst d f th ll (b) d d th ti l ( ) t b t k i t th ll bextend from the cell (b) and surround the particle (c) to be taken into the cell by

phagocytosis. The pseudopods fuse to form a phagosome (d) which fuses with aprimary lysosome (e) and the bacterium would then be degraded (f).

Phagocytosis

Pinocytosisextracellular fluid

cytoplasm

pinocytic vesicle

Pinocytosis. Membrane folds inward forming apinocytic vesicle.

PinocytosisPinocytosis

Receptor-pmediated

endocytosisendocytosis

Receptor-mediated endocytosis

Exocytosist ll l fl idextracellular fluid

cytoplasm

secretory vesicle from Golgi

cytoplasm

secretory vesicle from Golgi complex

Exocytosis. The membrane of the secretory vesicle fuses withExocytosis. The membrane of the secretory vesicle fuses withthat of the plasma membrane and the secretory product isreleased into the exterior of the cell.

ExocytosisExocytosis

Endocytosis and exocytosis

Salamat!Salamat!