S3T1: Movement Flashcards
(6 cards)
What is diffusion?
Net movement of molecules down a concentration gradient, from a region of higher concentration to a region of lower concentration.
What is osmosis?
Net movement of water molecules across a partially permeable membrane, from a solution of higher water potential to a solution of lower water potential.
What happens to plant cells in a) hypertonic solution b) hypotonic solution?
a) Cell sap has higher water potential than solution, water leaves cell sap through partially permeable membrane via osmosis. Cell membrane detaches from cell wall and plasmolyses.
b) Cell sap has lower water potential than solution, water enters cell sap through partially permeable membrane via osmosis. Vacuole expands, cell contents pushed against cell wall, cell enlargens and becomes turgid.
What happens to animal cells in a) hypertonic solution b) hypotonic solution?
a) Cytoplasm has higher water potential than solution, water leaves cytoplasm through partially permeable membrane via osmosis. Cell shrinks and becomes shriveled (red blood cell crenates)
b) Cytoplasm has lower water potential than solution, water enters cytoplasm through partially permeable membrane via osmosis. Cell expands, bursts/ lyses.
What is active transport?
Movement of ions/ molecules across a partially permeable membrane, from a region of lower concentration to a region of higher concentration against a concentration gradient.
How does root hair cell uptake ions through active transport?
When concentration of mineral salts (ions) are higher in cell sap, they have carrier proteins in cell membrane to bring mineral salts from soil to cell sap against concentration gradient, further increasing concentration of mineral ions. Now, cell sap has a lower water potential and can bring water across partially permeable membrane from the soil.
