Active TransportActive Transport

Chapter 7-3 Chapter 7-3

Active Transport Active Transport

Remember: in diffusion, solute molecules Remember: in diffusion, solute molecules move from HIGH conc. move from HIGH conc. LOW conc. LOW conc.

But sometimes, it is necessary to move But sometimes, it is necessary to move solute molecules against the concentration solute molecules against the concentration gradient!! gradient!!

Active TransportActive Transport

Active Transport: Active Transport: often involves often involves movement of solute movement of solute molecules from molecules from

LOW concentration LOW concentration HIGH concentrationHIGH concentration

Active Transport Active Transport

Active transport requires Active transport requires ENERGY!!!! ENERGY!!!!

What kind of energy do you think active What kind of energy do you think active transport uses?? Hint: it’s the product of transport uses?? Hint: it’s the product of cellular respiration cellular respiration

Active Transport: ProteinsActive Transport: Proteins

Comparison of Cellular TransportComparison of Cellular Transport

Transport by the Cell MembraneTransport by the Cell Membrane

Some larger molecules can only be Some larger molecules can only be transported into and out of the cell by transported into and out of the cell by movement of the cell membrane itself! movement of the cell membrane itself!

Examples: endocytosis, exocytosisExamples: endocytosis, exocytosis

Active Transport: EndocytosisActive Transport: Endocytosis

Endocytosis: process of taking material Endocytosis: process of taking material intointo the cell by means of infoldings of the the cell by means of infoldings of the cell membrane cell membrane

Food, molecules, even whole cells are Food, molecules, even whole cells are “consumed” by the cell via endocytosis“consumed” by the cell via endocytosis

Examples: phagocytosis, pinocytosisExamples: phagocytosis, pinocytosis

EndocytosisEndocytosis

PhagocytosisPhagocytosis

Phagocytosis means “cell eating”; method Phagocytosis means “cell eating”; method used to take in “food” molecules used to take in “food” molecules

Phagocytosis: cytoplasm surrounds “food” Phagocytosis: cytoplasm surrounds “food” particle, forms a vacuole, then engulfs the particle, forms a vacuole, then engulfs the vacuolevacuole

PhagocytosisPhagocytosis

PhagocytosisPhagocytosis

PinocytosisPinocytosis

Pinocytosis: method used to take in liquid Pinocytosis: method used to take in liquid

Pinocytosis: pockets form along the cell Pinocytosis: pockets form along the cell membrane, pockets fill with liquid, pockets membrane, pockets fill with liquid, pockets pinch off to form vacuoles within the cell pinch off to form vacuoles within the cell

PinocytosisPinocytosis

Phagocytosis vs. PinocytosisPhagocytosis vs. Pinocytosis

Active Transport: ExocytosisActive Transport: Exocytosis

Exocytosis: membrane of a vacuole (or Exocytosis: membrane of a vacuole (or lysosome) fuses with the cell membrane lysosome) fuses with the cell membrane and expels waste material into the and expels waste material into the extracellular environment extracellular environment

ExocytosisExocytosis