Lecture 9 Flashcards
Two types of transport through membrane
Passive and active
Diff between passive and active transport
Passive : no energy
Active : energy
Types of passive transport
Osmosis
Diffusion
Facilitated diffusion
Types of active transport
Primary
Secondary
Vesicular
What is primary active transport
Protein pump uses ATP to move solutes from low to high concentration
Secondary transport
Uses transmembrane electrochemical gradient of ions to provide E to bring components against concentration gradient
Vesicular transport types
Endocytosis and exocytosis
What is a concentration gradient
One area has a lower [] and one has a higher
What can cross freely through membrane by diffusion
Lipid soluable (hydrophobic), o2, co2
What happens at equilibrium
Molecules keep moving without a net mouvement or change in []
Rate/speed of diffusion depends on (3)
- Concentration (more = faster bc more collision)
- Molecular size
- Temperature (higher increases speed)
The more lilid soluble, the more
It will diffuse across membrane
Equilibrium in organisms rarely or frequently occurs?
Very rarely (ex o2 in and co2 out constantly)
What is osmolarity
Total [] of dissolved particles in solution
Osmolarity formula
Molarity x n (number of particles in solution)
Ex of osmolarity : 0.3M of NaCl = ?
0,3 x 2 = 0,6 osmol/L
Hypertonic
Greater [] of solute
Hypotonic
Lesser [] of solute
Isotonic
Same [] of solute
If 2 solutions have same osmolarity = same ?
Tonicity (isotonic)
Concentration gradient determined by difference in ?
TOTAL solute [] (NOT nb of nature if solute)
What is tonicity affected by
Presence of non penetrating solutes in water and net mvmt of water
Tonicity is a description of how
Solutions affect a cell’s shape
Crenation
Cell shrinks (occurs im hypertonic solutions)
Hemolysis
Cell bursts (in hypotonic solutions)
What helps facilitate diffusion
Transmembrane proteins
Which type of transport brings molecules down their gradient
Passive
Transmembrane proteins
Carrier (specific for one chemical, shale change, sugars, am ac)
channel (mostly ions
Water specific channels
Aquaporins
Can water cross through simple diffusion
Yes (bc small) but very slow, facilitated is faster
Why can’t sodium diffuse out of cell
Bc can’t diffuse from low to high []
Mouvement of hydrophilic molecules against their gradient
Actuve
What does active transport require
ATP and carrier protein
Primary active transport creates what
Gradient which provides energy for secondary active transport
How is electrochemical gradient created
When primary active transport moves ions
Source of energy for secondary transport
Electrochemical gradient
Popular pump
Na+-K+ pump
When Na+ ions go outside (after primary transport), when a channel protein opens, they move down their gradient (back into cell) and transport other substances (glucose) that way
Secondary active transport (just wanted to explain)
Two ways for glucose uptake to take place
Facilitated diffusion and secondary active transport
Exocytosis
Transport of very large molecules OUT of cell (ex insulin out of pancreatic cell)
Endocytosis
Transport of very large molecules into cell
