Transcript Cellular Transport EOCT Revu 2011

CELL TRANSPORT
PASSIVE & ACTIVE TRANSPORT
CLASSROOM BOOK: 7-3
ZEBRA BOOK: 7-4
Cell Membrane
 MAIN FUNCTION IS TO REGULATE
WHAT ENTERS AND LEAVES THE
CELL TO MAINTAIN HOMEOSTASIS
 A STABLE, INTERNAL
ENVIRONMENT
HOMEOSTASIS - EXAMPLES OF
 SHIVERING WHEN COLD TO
GENERATE HEAT WITHIN THE
BODY
 SWEATING WHEN HOT TO
COOL THE INTERNAL CORE
TEMPERATURE.
THE CELL MEMBRANE
MADE OF
PHOSPHOLIPIDS
AND PROTEINS
LIPID BILAYER STRUCTURE
LIPID BILAYER
 TWO LAYERS OF
PHOSPHOLIPIDS
 PHOSPHATE HEAD IS POLAR
(WATER LOVING)
 FATTY ACID TAILS ARE NON
POLAR (WATER HATING)
PROTEINS
ARE EMBEDDED IN THE
CELL MEMBRANE THAT
ACT AS DOORS SO
SUBSTANCES CAN ENTER
AND EXIT.
CELL MEMBRANE
ALSO REFERRED TO AS:
 LIPID BILAYER
 PHOSPHOLIPID BILAYER
 PLASMA MEMBRANE
SELECTIVELY PERMEABLE
 THE CELL MEMBRANE WILL ALLOW
CERTAIN SUBSTANCES TO PASS
THROUGH EASILY
 EX: WATER, SUGARS, OXYGEN,
CARBON DIOXIDE
SELECTIVELY PERMEABLE
 AND, KEEP OTHER SUBSTANCES
FROM PASSING THROUGH THE CELL
MEMBRANE
 EX. LARGE LIPIDS, PROTEINS,
CARBOHYDRATES,
TRANSPORT IN THE CELL
CAN BE
PASSIVE TRANSPORT
OR
ACTIVE TRANSPORT
PASSIVE TRANSPORT
 NO ENERGY INPUT BY THE CELL
IS NEEDED FOR MOVEMENT TO
OCCUR
 THE 3 TYPES OF PASSIVE
TRANSPORT ARE:
 DIFFUSION
 OSMOSIS
 FACILITATED DIFFUSION
DIFFUSION
 THE MOVEMENT OF MOLECULES
FROM AN AREA OF HIGH
CONCENTRATION TO AN AREA OF
LOW CONCENTRATION ACROSS A
SELECTIVELY PERMEABLE MEMBRANE
OSMOSIS
 THE MOVEMENT OF WATER
FROM AN AREA OF HIGH
CONCENTRATION TO AN AREA
OF LOW CONCENTRATION
ACROSS A SELECTIVELY
PERMEABLE MEMBRANE.
 THE WAY THAT WATER MOVES
IN LIVING ORGANISMS
OSMOSIS
IS HOW WATER
MOVES IN LIVING
ORGANISMS
THREE TYPES OF OSMOTIC
SOLUTIONS
HYPERTONIC
HYPOTONIC
ISOTONIC
OSMOTIC SOLUTIONS
 HYPOTONIC - THE
CONCENTRATION OF SOLUTE
MOLECULES OUTSIDE OF THE CELL
IS LOWER THAN THE
CONCENTRATION OF SOLUTE
MOLECULES IN THE CYTOPLASM.
 (LESS WATER INSIDE OF THE CELL
THAN OUTSIDE OF THE CELL)
Hypotonic Solutions
cell: L water, H solute
Environment: H water, L solute,
hypotonic to cell
Hypotonic:
Water enters cell.
Cell swells and bursts (cytolysis).
Give plant cells shape and support.
Cell hypertonic to environment.
Environment hypotonic to cell.
RED BLOOD CELL IN A
HYPOTONIC SOLUTION
WHICH WAY DOES THE
WATER MOVE?
WHY?
OSMOTIC SOLUTIONS
 HYPERTONIC – THE
CONCENTRATION OF SOLUTE
MOLECULES OUTSIDE OF THE CELL
IS HIGHER THAN THE
CONCENTRATION OF SOLUTE
MOLECULES INSIDE OF THE CELL.
 (MORE WATER INSIDE OF THE
CELL THAN OUTSIDE OF THE CELL)
Hypertonic Solutions
Cell: H water; L solute
Environment: L water, H solute
Hypertonic:
Water exits cell.
Cell shrinks (plasmolysis) due to
loss.
Cell hypotonic to environment.
Environment hypertonic to cell.
water
RED BLOOD CELL IN A
HYPERTONIC SOLUTION
WHICH WAY DOES
THE WATER MOVE?
WHY?
OSMOTIC SOLUTIONS
 ISOTONIC – THE
CONCENTRATION OF SOLUTES
INSIDE AND OUTSIDE OF THE
CELL ARE EQUAL.
 (THE AMOUNT OF WATER INSIDE
AND OUTSIDE OF THE CELL IS
EQUAL).
Isotonic Solutions
Isotonic:
Water in = Water out
No net movement of water.
Molecules in equilibrium.
Normal state for animal cells.
Cell in homeo
RED BLOOD CELL IN AN
ISOTONIC SOLUTION
WHICH WAY DOES
THE WATER MOVE?
WHY?
FACILITATED DIFFUSION
THE MOVEMENT OF
MOLECULES ACROSS A
SELECTIVELY PERMEABLE
MEMBRANE WITH THE
ASSISTANCE OF CARRIER
PROTEINS IN THE
MEMBRANE
FACILITATED DIFFUSION
 PROCESS USED FOR MOLECULES
THAT CANNOT DIFFUSE RAPIDLY
THROUGH CELL MEMBRANES
 MOLECULES MAY NOT BE
SOLUBLE TO LIPIDS OR TOO
LARGE TO PASS THROUGH THE
MEMBRANE
EXAMPLE OF FACILITATED
DIFFUSION
TRANSPORT OF GLUCOSE
CARRIER PROTEINS MOVE
GLUCOSE OUT OF THE
CELL TO WHERE IT IS
NEEDED
ACTIVE TRANSPORT
 REQUIRES ENERGY INPUT BY
THE CELL FOR MOVEMENT TO
OCCUR.
 INCLUDES:




SODIUM-POTASSIUM PUMP
ENDOCYTOSIS
EXOCYTOSIS
ELECTRON TRANSPORT CHAIN
ENDOCYTOSIS(ENTERING THE
CELL)
 TAKING MATERIAL INTO THE
CELL BY MEANS OF INFOLDINGS
OR POCKETS OF THE CELL
MEMBRANE
 THE POCKET FORMS A VACUOLE
AND CARRIES THE MATERIAL
Endocytosis
ENDOCYTOSIS – TWO TYPES
PINOCYTOSIS – THE
TRANSPORT OF SOLUTES OR
FLUIDS
PHAGOCYTOSIS – THE
TRANSPORT OF LARGE
PARTICLES OR WHOLE
CELLS
EXOCYTOSIS(EXITING THE
CELL)
 THE PROCESS BY WHICH CELLS
REMOVE MATERIALS FROM THE
CELL
 REVERSE PROCESS OF
ENDOCYTOSIS
EXOCYTOSIS