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CELLS need to take in nutrients, oxygen, and water in order to grow, develop, and divide. They also need to remove materials. CELL MEMBRANE - selectively permeable – limits movements of materials in/out of cell How is this done?.
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CELLS need to take in nutrients, oxygen, and water in order to grow, develop, and divide. They also need to remove materials. • CELL MEMBRANE • - selectively permeable – limits movements of materials in/out of cell How is this done?
DIFFUSION – (passive transport = no energy required) – molecules move from high concentration to low
Diffusion • In diffusion, molecules move from an area of higher concentration to an area of lower concentration.
OSMOSIS - water molecules moving from high to low; this is also passive transport which means no energy required
Osmosis In osmosis, water diffuses through a selectively permeable membrane.
Water and Living Things About two-thirds of the human body is water. Cells cannot function adequately without water.
Passive and Active Transport Passive and active transport are two processes by which materials pass through the cell membrane. Active transport requires the cell to use its own energy, while passive transport does not.
ACTIVE TRANSPORT - movement of particles that requires energy ; usually because moving into an area that already has a high concentration of a substance
more active transport examples: • endocytosis • “endo”= inside • “cyt”= cell • membrane folds around particle; vesicle • exocytosis • “exo”= exit • “cyt”=cell • vesicles inside cell carry particles to membrane to be released