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DIFFUSION AND 7TH GRADE SCIENCE S TABILITY – KEEP A CONSTANT INTERNAL STATE IN A CHANGING ENVIRONMENT

TO MAINTAIN HOMEOSTASIS, CELLS MUST: - EXCHANGE MATERIALS - ELIMINATE WASTE - OBTAIN AND USE ENERGY - MAKE NEW CELLS EXCHANGE OF MATERIALS FOR THE

CELL ARE SEMIPERMEABLE – ONLY CERTAIN P ARTICLES CAN MOVE IN OR OUT OF CELL (S ELECTIVE)

: TRANSPORT OF MATERIALS STRAIGHT THROUGH THE CELL (DOES NOT USE ENERGY) • : TRANSPORT OF MATERIALS THROUGH CHANNELS IN (REQUIRES ENERGY)

Protein channel

energ y Gradient

Molecules move randomly from high concentration to low concentration. AND OSMOSIS (PASSIVE TRANSPORT) DIFFUSION OSMOSIS • MOVEMENT OFMOLECULES FROM • MOVEMENT OFWATER THROUGH A HIGH CONCENTRATION TO LOW FROM CONCENTRATION OF HIGHER TO LOWER CONCENTRATION

IN WHICH DIRECTION WILL THE PARTICLES MOVE OR DIFFUSE? ANSWER: THE PARTICLES DIFFUSE FROM MORE CONCENTRATED TO LESS CONCENTRATED! IN WHICH DIRECTION WILL THE MOVE? (OSMOSIS) ANSWER: THE WATER MOVES FROM LESS CONCENTRATE TO MORE CONCENTRATE!

water DIFFUSION AND OSMOSIS

CONCENTRATION GRADIENT: UNEVEN DISTRIBUTION OF A SUBSTANCE ACROSS A BORDER SOLUTE: PARTICLES DISSOLVED IN WATER : MIXTURE OF WATER AND SOLUTE

• ISOTONIC: EQUILIBRIUM, SAME CONCENTRATION IN 2 DIFFERENT AREAS

• HYPERTONIC: THE WITHHIGHER CONCENTRATION OF SOLUTE (LESS WATER)

• HYPOTONIC: THE AREA WITHLOWER CONCENTRATIONOF SOLUTE (MORE WATER) WATER

• ES S ENTIAL FOR CELLS • WATER MOVES ACROSS THE CELL MEMBRANE BY OSMOSIS IT DEPENDS ON THE CONCENTRATION OF WATER INSIDE AND OUTSIDE THE CELL Follow the Water

cell swells “Salt Sucks”

cell shrinks VESICLE TRANSPORT

ENDOCYTOSIS • PROCESS IN WHICH CELLS • PROCESS IN WHICH PARTICLES SURROUND AND ENCLOSE A ARE ENCLOSED IN A VESICLE IN PARTICLE IN A VESICLE TO BRING IT THE CELL AND THEN RELEASED INTO THE CELL FROM THE CELL • IT REQUIRES ENERGY • OPPOSITE OF ENDOCYTOSIS • ENDO = IN • EXO = OUT ENDO

EXO Make a Google Doc to answer these questions. Turn in on this assignment.

1. De fin e d iffu s io n . 2. What is moving during osmosis? 3. Which type of cellular tra nsport requires energy---pa ssive tra nsport or a ctive tra nsport? 4. What are two types of passive transport? 5. Which way does the concentration gradient move? 6. What is Brownian movement?