Unit 1- The cell membrane Flashcards
what is the fluid mosaic model
the cell membrane
-lipid bilayer
-proteins within
*not ridgid, lipids and proteins can move laterally
what factors make the phospholipid bilayer FLUID
-the fatty acid chains of phospholipids (unstaurated)
-temp (high, more fluid) (cold, less fluid)
-Sterols (cholesterol regulates temp, making sure it doesn’t become too hot not too cold)
what factors make the phospholipid bilayer SEMIPERMEABLE
-hydrophobic core prevents hydrophilic structures but allows hydrophobic structures
what are integral proteins
proteins that span the lipid bilayer
where are proteins placed within the cell membrane
- non-polar regions of the protein are in the interior bilayer
- polar regions of the protein protrude both sides of the bilayer
3.
what is a glycolipid
lipid with a carbohydrate chain attached to it on the extracellular surface of the cell
what is a glycoprotein
a protein with an extra carbohydrate attached to it on the surface of the cell
what are functions of glycoproteins and glycolipids
-receptors
-cell recognition
-hormonal responses
-neurotransmission
what are the criteria for passive transport
-small nonpolar molecule
-high & low concentration
-no use of chem energy
what are the 4 types of passive transport
-simple diffusion
-facilitated diffusion
-osmosis
what is simple diffusion
what can pass through
-molecules pass through bilipid layer
-small nonpolar molecules (O2, CO2, N2)
-small polar molecules (H2O, glycerol)
what is facilitated diffusion
-molecules move with the help of transportive proteins
what are the two transportive proteins
-channel proteins- like tunnels
-carrier proteins- like elevators
what is osmosis
what can pass through
-water molecules pass directly through the lipid bilayer or through a pore
-water
*Moves from high concentration to low concentration
how does water move
water always moves towards hyper solution (high solute)
what is a hypotonic solution
what happens to the cell
-concentration lowwqh outside cell, concentration high inside cell
-water moves into cell
-cell cannot hold that much water to it lyses (bursts)
what is a isotonic solution
what happens to the cell
-the concentration is the same outside and inside the cell
-the cell stays normal
what is a hypertonic solution
what happens to the cell
-concentration outside the cell is higher, concentration inside the cell is low
-the cell shrivels
what is a diseases relating to defective channel proteins
cystic fibrosis
-channel protein does not move chloride ions
-causes thick, sticky, mucus
what is a diseases relating to defective carrier proteins
cystin urea
when does active transport occur
when substances must travel against the concentration gradient (travel from lower to higher)
what does active transport require
-pumps
-energy (ATP)
what does ATP stand for
where does it’s energy come from
adenosine tri-phosphate
energy stored in bonds connecting phosphate molecules together (Phosphates are super -ve and want to push away from eachother)
what is primary active transport
-uses ATP to power pumps that move molecules across membrane against the concentration gradient
-positively charged ions
what is the electrochemical gradient
difference in electrical potential and difference in concentration gradients
what are peripheral membrane proteins
proteins anchored to a phospholipid in one layer of the membrane
what do peripheral membrane proteins do
-receptor recognition
-cell signaling
-carry electrons
what is secondary active transport
transport of molecules across the cell membrane using energy other then ATP, energy from the electrochemical gradient
what are the stages of secondary active transport
- sodium ions move low [ ] to high [ ] using a Na/K pump
-this creates a build up of Na ions outside the cell creating an electrochemical gradient - Na ions want to move high [ ] to low [ ]. They take glucose along
what is symport
substances moving through cell membrane pull other substances through cell membrane in SAME direction
what is symport
substances moving through cell membrane pull other substances through cell membrane in SAME direction
what is anti port
when substances moving through the membrane and pull other substances through the cell membrane the opposite direction
