Active Transport
What does “against” the concentration gradient mean?? Active Transport Requires energy in the form of ATP (useful cellular energy) movement against the concentration gradient What does “against” the concentration gradient mean??
2 methods of Active Transport Pumps Change in the cell membrane (aka vesicular transport)
Active Transport Pumps: Requires a protein channel called a “pump” Requires ATP Movement from low concentration to high concentration moving up the hill hi concentration low concentration Works in the opposite direction of facilitated diffusion.
Active transport pump Energy (by way of ATP) forces materials through a protein in the membrane against concentration gradient. You do not need to understand HOW this works…just WHY a cell would require energy in order to do this.
Why Pump? Which way would the potassium ions (K+) tend to go? (Would they go into the cell or out of the cell? How do you know?) Nerve cells need a difference in ions (charge) on either side of the membrane so they can fire.
Change in cell membrane (2nd type of active transport process) A.K.A. “Vesicular Transport” - Used for large substances or large amounts of substances. Two types: Endocytosis: IN to the cell (ENTER) Exocytosis: OUT of the cell (EXIT)
Change in cell membrane (2nd type of active transport process) Endocytosis (IN) Takes in (engulfs) large material Cell membrane moves in until it encapsulates material, becoming a vesicle.
Endocytosis: (IN) Two types: Phagocytosis Pinocytosis
Phagocytosis: “Cell Eating” Pseudopods engulf material with extensions of the cell membrane. E.g. White blood cell taking in foreign material for destruction. E.g. Amoeba engulfing a diatom
Phagocytosis:
Pinocytosis: “Cell Drinking” Membrane wraps around a big drop of solution (solute & solvent) and pulls it in.
Pinocytosis:
Change in cell membrane (2nd type of active transport process) Exocytosis (OUT) Vesicle that gets rid of large material Vesicle fuses with cell membrane, releasing contents to outside of cell. E.g. Waste E.g. Digestive enzymes A goblet cell procedures mucin which when dissolved in water is the main component of mucus. What is the purpose of mucus?
Exocytosis: (OUT) RNA Rough ER Golgi apparatus Protein in vesicle Plasma membrane
Figure 7.14 The formation and functions of lysosomes (Layer 1)
Figure 7.14 The formation and functions of lysosomes (Layer 2)
Figure 7.14 The formation and functions of lysosomes (Layer 3) Often used to recycle cell parts (do NOT need to know for test)