Movement Through Cell Membranes: Diffusion, Osmosis, and Active Transport
This guide explores the processes of passive and active movement across cell membranes. Passive movement includes diffusion and osmosis, where molecules like oxygen and water spontaneously move from high to low concentrations. Facilitated diffusion requires protein carriers for substances such as glucose. Active transport, needing energy (ATP), moves particles against their concentration gradient. Endocytosis and exocytosis are processes for large particles' uptake and release. Understanding these mechanisms is essential for grasping how cells interact with their environment.
Movement Through Cell Membranes: Diffusion, Osmosis, and Active Transport
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Presentation Transcript
HAP 3.3 “Movement Through Cell Membranes”
I. Passive Movement A. Diffusion 1. Def – molecules or ions spontaneously move from high to low concentrations. 2. Quick movement a. 1000 mph 3. Equilibrium – uniform distribution 4. Requirements for a cell… a. Membrane is permeable b. Concentration gradient
5. Ex: pg. 60 “consider oxygen and carbon dioxide…” B. Facilitated Diffusion 1. Require help from protein carriers 2. Ex: glucose and amino acids 3. Types: a. Channel b. Carrier c. Gate
C. Osmosis 1. Def – water molecules diffuse from high to low concentrations 2. Terms… a. Isotonic = equal pressure b. Hypertonic = movement out… c. Hypotonic = movement in…
II. Active Movement A. Active Transport 1. Def – moves particles from low to high concentrations. a. Requires energy (ATP) b. a.k.a. pumps c. Include…sugar, a.a., ions d. Also used in digestion
B. Endocytosis and Exocytosis 1. Endocytosis – large particle enters a. Pinocytosis – “cell drinking” b. Phagocytosis – “cell eating” c. Receptor aided – pg. 65 2. Exocytosis – large particle leaves a. Wastes and hormones
