Cell Membrane. Passive Transport Flashcards
Why do passive processes require no energy
They don’t oppose entropy
Difference between the passive processes: filtration and convection
Filtration- dependent on differences in pressure that occurs normally in environment
Convection- when substance is moving along with another ie transport of substances in blood is convection
What are cell membranes composed of
Lipids proteins carbohydrates
What is the phospholipid component of membrane
Hydrophilic head- phosphorylated glycerol
Hydrophobic tail- 2 fatty acids
Amphipathic
Lipid bilayer
Protein component of cell membrane
Integral and peripheral proteins- creates fluid mosaic model
Integral- embedded and anchored to membrane by hydrophobic interactions. They can spam membrane (transmembrane) or not
Peripheral-are not embedded in the membrane and are not covalently bound to cell membrane components.
Loosely attached to side of membrane by electrostatic interactions.
Eg ankyrin, which “anchors” the cytoskeleton of red blood cells to an integral mem- brane transport protein,
Downhill/uphill transport
Downhill- simple or facilitated diffusion, no energy
Uphill-primary or secondary active transport and requires energy
What are the features of carrier mediated transport
Saturation, stereo specificity, competition
What is saturation for carrier mediated transport
carrier proteins have a limited number of binding sites for the solute
What is stereospecificity for carrier mediated proteins
carrier proteins are specific forn partivular solute
Eg may recognise d-glucose but not l-glucose
Competition for carrier mediated proteins
Even though carriers sterosoecific there is still a change they recognise and bind chemically related solutes
What is simple diffusion and what causes it
The net movement of particles from higher conc to lower conc until equilibrium reached
Caused by random movement of particles
What is osmolarity
the concentration of osmotically active particles in a solution.
It is a colligative propert meaning it depends on the ratio of solute to solvent. Can be measured by freezing point depression
What is osmosis
Osmosis is the flow of water across a semipermeable membrane from a solution with low
solute concentration to a solution with high solute concentration.
When does osmotic pressure increase
When solute concentration increases. So the greaterr the water flow into it
Solution with higher osmotic pressure
Solution with lower osmotic pressure
Solutions with equal osmotic pressure
hypertonic
hypotonic
isotonic
