Chapter 3 - Cell Membranes And Transport Flashcards
Phospholipid bilayer
Hydrophilic heads
Hydrophobic tails
Double membrane so enclosed
How thick is the phospholipid bilayer
7-8nm
Extrinsic protiens
Outer surface of plasma membrane and are hydrophilic
Intrinsic protiens
Hydrophobic (channel/carrier proteins) and held in the plasma membrane
Movement of molecules
The higher the temperature the more kinetic energy so the faster they move
Diffusion
Movement of molecules from and area of high to low concentration down the concentration gradient
Facilitated diffusion
The rapid passive movement of molecules across membranes down a concentration gradient aided by carrier and channel protiens
For hydrophilic molecules
Active transport
Movement of molecules across membranes against the concentration gradient from low to high concentration requiring ATP therefore oxygen
Channel protiens
Temporary hydrophilic pore that spans a membranes width which small ions and water soluble molecules can cross via facillitated diffusion
Carrier protein
Carries molecules via active transport ATP is required
Glycoproteins
Carbohydrates linked to a protein and used for cell to cell recognition
Glycolipid
Lipid with a carbohydrates and used in cell to cell recognition
Cholesterol
Steroid component making it more rigid and stable
Osmosis
Form of diffusion high to low water potential down a water potential gradient down a water potential gradient through a selectively permeable membrane WATER ONLY
Water potential
Water potential of the cell = solute potential + water potential and has the symbol (psi)
What liquid has the highest water potential and what is it
Distilled water 0 kph
Solute potential
Presence of solute molecules and always has a negative value as they lower water potential of the cell
Pressure potential
Pressure produced by the cell wall pushing back against the cell surface membrane in plants