Chapter 4 Study Guide
Chapter 4: Membrane Structure and Function
Fluid Mosaic Model
1. Consistency of membrane is solid enough to form a boundary, but flexible and permeable like a fluid.
2. Proteins scattered throughout
- Embedded or on the surface
- Can move around laterally 3. Phospholipid from bilayer, make up most of membrane
4. Glycolipids have carbohydrate chains attached.
5. Hydrophilic heads point out/into the cell
6. Hydrophobic tails point out towards each other
Proteins
1. Glycoproteins: have carb chains attached protein
-For cell recognition (Recognize when it is being invaded by pathogens)
- Recognize cells as self
2. Peripheral Proteins: associated with one side or other of membrane; anchored by cytoskeleton
*Function: structural; stabilize and shape membrane signaling pathways.
3. Integral Proteins: span entire membrane; protrude on one side and/or other; float around.
4. Cholesterol: in animals; stiffens and strengthens regulate fluidity.
Some Specific on Integral Proteins
Channel Proteins: pass molecules through; contain channel down middle. – ions and small polar molecules.
Gated Non-Gated
Carrier Proteins: pass molecule through by combining with it; shape specific
-Sugars/amino acids
-Depending on ion concentration -Movement of molecules if facilitated
-Diffusion work facilitated: moving molecules from high concentration to low concentration.
Cell Recognition Proteins: glycoproteins
Receptor Proteins: shape specific; specific molecule binds, shape changes, triggering cellular response.
-Cause the sodium to enter another ligand gated ion
Enzymatic Proteins: Carry out metabolic reactions directly; catalyze specific reactions.
Membrane Permeability
*Differentially permeable
Passive Transport:
-Requires no energy to move substances across membrane.
Atoms, molecules and small particles in constant motion (Browninan); can move any direction;
-Usually move from area of higher concentration to area of lower concentration –
Fluid Mosaic Model
1. Consistency of membrane is solid enough to form a boundary, but flexible and permeable like a fluid.
2. Proteins scattered throughout
- Embedded or on the surface
- Can move around laterally 3. Phospholipid from bilayer, make up most of membrane
4. Glycolipids have carbohydrate chains attached.
5. Hydrophilic heads point out/into the cell
6. Hydrophobic tails point out towards each other
Proteins
1. Glycoproteins: have carb chains attached protein
-For cell recognition (Recognize when it is being invaded by pathogens)
- Recognize cells as self
2. Peripheral Proteins: associated with one side or other of membrane; anchored by cytoskeleton
*Function: structural; stabilize and shape membrane signaling pathways.
3. Integral Proteins: span entire membrane; protrude on one side and/or other; float around.
4. Cholesterol: in animals; stiffens and strengthens regulate fluidity.
Some Specific on Integral Proteins
Channel Proteins: pass molecules through; contain channel down middle. – ions and small polar molecules.
Gated Non-Gated
Carrier Proteins: pass molecule through by combining with it; shape specific
-Sugars/amino acids
-Depending on ion concentration -Movement of molecules if facilitated
-Diffusion work facilitated: moving molecules from high concentration to low concentration.
Cell Recognition Proteins: glycoproteins
Receptor Proteins: shape specific; specific molecule binds, shape changes, triggering cellular response.
-Cause the sodium to enter another ligand gated ion
Enzymatic Proteins: Carry out metabolic reactions directly; catalyze specific reactions.
Membrane Permeability
*Differentially permeable
Passive Transport:
-Requires no energy to move substances across membrane.
Atoms, molecules and small particles in constant motion (Browninan); can move any direction;
-Usually move from area of higher concentration to area of lower concentration –