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Learn about the cell membrane's structure, functions, and transport processes, including passive and active mechanisms like facilitated diffusion and vesicular transport. Understand terms like osmosis and hypertonic solutions.
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Notebook Page 33 & 34 THE CELLMembrane
Cell Membrane Also called the Plasma Membrane
Fluid Mosaic Model 1. Made of phospholipidbilayer • hydrophobictails(repels water) point inward Chains of fatty acids • hydrophilic heads(attracts water) point outward Made of an alcohol and glycerol
The phospholipids can move sideways to allow water and other Non-Polar molecules to pass through into or out of the cell
Membrane Transport A. Passive Transport • requires no energy • occurs with the concentration gradient 3 examples a. Diffusion
Fluid Mosaic Model Made of proteins, carbohydrates and cholesterol
Fluid Mosaic Model 1. Cholesterol – another type of lipid In the cell membrane a. Cholesterol mc • are scattered throughout membrane • help stabilize membrane • Make the membrane more fluid
functions Proteins
Proteins, carbohydrates and cholesterol Proteins 1) Kinds: • Integral • Or transmembrane proteins • Go all the way through • Peripheral • Only on one side
Large molecules • Like proteins or carbohydrates use proteins to help move across cell membranes. • Some of the membrane protein have carbohydrate parts attached to help cells recognize each other and certain molecules
Cell Membrane Function 1. Cell Signaling • Selective transport • Excretion of wastes • Structural support
Membrane Transport Membrane Permeability Selectively permeable
- diffusion of water examples Osmosis Water moves from high water (low solute) concentration to low water. Moving down with the concentration gradient
Important Terms • Hypotonic Solution has lower % solute than the cell; water moves into the cell
Important Terms • Hypertonic • Hypotonic Solution has higher % solute than the cell; water moves out of the cell
Important Terms • Hypertonic • Hypotonic • Isotonic Solution has same % solute as the cell; water movement in = out
Passive Transport - no energy required examples Facilitated diffusion • uses membrane proteins • example: glucose is carried by permease
Passive Transport examples Filtration • Occurs when pressure is exerted on the fluids and solutes • Kidneys • Dialysis
movement of mc against the concentration gradient Active Transport • requires energy – ATP Uses 40% of ATP in cell!
Kinds of Active Transport Sodium Potassium pump move ions into and out of the cell against their gradients Helps muscle cells contract
Active Transport Pumps Transmembrane /intregral proteins – Change shape to move ions
3. Kinds of Active Transportb. Vesicular transport 1) Endocytosis
Endocytosis phagocytosis – “cell eating”, pinocytosis - “cell drinking”
Kinds of Active TransportVesicular transport exocytosis