🧬 The Cell Membrane and Transport: Infographic Study Guide
1. The Fluid Mosaic Model (The Membrane Structure)
The cell membrane (or plasma membrane) is a selectively permeable boundary that controls everything
entering and leaving the cell. It's described as a Fluid Mosaic because it's a dynamic, liquid-like
structure with a mosaic of proteins embedded within it.
Compo Description & Function Diagram Labeling
nent
Phosph The basic framework. Two layers of phospholipids: Hydrophilic Blue Heads ∣ Orange
olipid (water-loving) Heads face the watery environment (outside and Tails
Bilayer cytoplasm). Hydrophobic (water-fearing) Tails face inward, away
from water.
Protein Integral Proteins (fully embedded, often spanning the Green
s membrane) and Peripheral Proteins (loosely bound to the Transporters, Enzymes
surface). Carry out most membrane functions.
Choles Wedged between phospholipids. Acts as a fluidity buffer—it Purple
terol keeps the membrane from becoming too rigid when cold and too Fluidity Regulator
fluid when hot.
Carboh Attached to lipids (Glycolipids) or proteins (Glycoproteins). Act Red Cell-ID Tags
ydrates as cell-to-cell recognition markers ("ID tags").
2. Membrane Proteins: Six Major Functions
Membrane proteins are the workers of the cell boundary. They perform six critical tasks:
1. Transport: Shuttling substances across the membrane.
2. Enzymatic Activity: Catalyzing chemical reactions along the membrane surface.
3. Signal Transduction: Binding a ligand (signaling molecule) to trigger a response inside the cell.
4. Cell-Cell Recognition: Glycoproteins act as identifiers for other cells.
5. Intercellular Joining: Proteins on adjacent cells hook together (e.g., gap junctions).
6. Attachment: Anchoring the cytoskeleton (inside) and the Extracellular Matrix (outside).
3. Passive Transport (The Downhill Flow)
Passive transport moves substances down their concentration gradient (from High concentration to
Low concentration). No energy (ATP) is required.
Comparison of Passive Transport Types
Type of Energy Used? Specificit Example/What Moves?
Transport y
Simple NO (Kinetic Non- Small, non-polar molecules (O2 , CO2 )
Diffusion Energy) specific
1. The Fluid Mosaic Model (The Membrane Structure)
The cell membrane (or plasma membrane) is a selectively permeable boundary that controls everything
entering and leaving the cell. It's described as a Fluid Mosaic because it's a dynamic, liquid-like
structure with a mosaic of proteins embedded within it.
Compo Description & Function Diagram Labeling
nent
Phosph The basic framework. Two layers of phospholipids: Hydrophilic Blue Heads ∣ Orange
olipid (water-loving) Heads face the watery environment (outside and Tails
Bilayer cytoplasm). Hydrophobic (water-fearing) Tails face inward, away
from water.
Protein Integral Proteins (fully embedded, often spanning the Green
s membrane) and Peripheral Proteins (loosely bound to the Transporters, Enzymes
surface). Carry out most membrane functions.
Choles Wedged between phospholipids. Acts as a fluidity buffer—it Purple
terol keeps the membrane from becoming too rigid when cold and too Fluidity Regulator
fluid when hot.
Carboh Attached to lipids (Glycolipids) or proteins (Glycoproteins). Act Red Cell-ID Tags
ydrates as cell-to-cell recognition markers ("ID tags").
2. Membrane Proteins: Six Major Functions
Membrane proteins are the workers of the cell boundary. They perform six critical tasks:
1. Transport: Shuttling substances across the membrane.
2. Enzymatic Activity: Catalyzing chemical reactions along the membrane surface.
3. Signal Transduction: Binding a ligand (signaling molecule) to trigger a response inside the cell.
4. Cell-Cell Recognition: Glycoproteins act as identifiers for other cells.
5. Intercellular Joining: Proteins on adjacent cells hook together (e.g., gap junctions).
6. Attachment: Anchoring the cytoskeleton (inside) and the Extracellular Matrix (outside).
3. Passive Transport (The Downhill Flow)
Passive transport moves substances down their concentration gradient (from High concentration to
Low concentration). No energy (ATP) is required.
Comparison of Passive Transport Types
Type of Energy Used? Specificit Example/What Moves?
Transport y
Simple NO (Kinetic Non- Small, non-polar molecules (O2 , CO2 )
Diffusion Energy) specific
