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Membrane Structure & Function. - Coggle Diagram
Membrane Structure & Function.
Cell Transport
Bulk Transport (Vesicles + ATP)
Moves large materials using vesicles.
Endocytosis:
Cell brings materials IN using a vesicle.
EX: White blood cell taking in bacteria.
Exocytosis:
Cell sends materials OUT using a vesicle.
EX: Nerve cell releasing neurotransmitters.
Active Transport (ATP)
Moves substances with energy (ATP), Low -> high.
Passive Transport (No ATP)
Moves substances without energy high -> low.
3 Types of Passive Transport:
Osmasis
WATER moves high water -> low
Facilitated diffusion
Molecules move high -> low using protein channels
Diffusion
Molecules that can move high -> low through the membrane
Cell Membrane are Fluid Mosaics
Fluidity
How easily lipids move.
EX: Cold-adapted organisms add unsaturated fats.
Lipid Composition
Different organisms have different membrane lipids.
EX: Arctic fish membrane stay flexible.
Mosaic
Membrane made of many mixed parts.
EX: Blood type markers & membrane carbohydrates.
Transport Proteins
Proteins that help things to cross the membrane.
Channel proteins:
Tunnels for ions/water.
EX: Sodium ion channel, aquaporin (water).
Carrier proteins:
Changes shape to move molecules.
EX: glucose carrier, amino acid carrier.
It's used in: Facilitated diffusion + active transport.
Fluidity of Membranes
How easily membrane lids and proteins move.
Temperature
Heat increases lipid movement.
EX: Warm= more fluid; Cold= less fluid.
Unsaturated Fatty Acids
Bent tails prevent tight packing-> more fluid
EX: plants add more unsaturated fats in cold.
Saturated Fatty Acids.
Straight tails pack tightly -> less fluid.
EX: Animals fats make membranes more rigid.
Cholesterol.
It prevents the membrane from becoming too fluid or too rigid.
EX: Stabilizes membrane during temperature changes.
Differences in Membrane Lipid Composition
Types:
Environmental/Species Differences
Lipids change with conditions.
EX: Winter wheat adds unsaturated lipids in autumn.
Membrane Asymmetry
Inner vs. outer layer lipids.
EX: Outer layer has more glycolipids.
Phospholipid Types
Different heads/tails.
EX: Nerve cells use special phospholipids.
Cholesterol Amount
More or less cholesterol.
EX: Animal Cells= cholesterol for stability.
Saturated vs. Unsaturated
Straight vs. bent tails.
EX: Cold-water fish= more unsaturated.
Membranes in Selective Permeability
Membrane controls what enters and exits.
Small Polar Molecules
Slow, limited.
EX: Water
Large Polar Molecules
Cannot pass without help
EX: glucose
Small Non-polar Molecules.
Pass easily.
EX: Example: O₂, CO₂.
Ions
Blocked without channels.
Na⁺, K⁺.
Transport Proteins
helps molecules cross though the cell.
ion channels, glucose carriers.