Topic 1.4 Membrane Transport Flashcards
what are the three types of membrane transport?
simple diffusion, facilitated diffusion, and osmosis
why is the membraned called the “fluid membrane”?
the phospholipid heads can move around and be permeable
the membrane is referred to being ( _ _ _ _)permeable
selectively
passive transport does not require…
energy, ATP
what concentration gradient do particles move in in passive transport?
higher to lower
what kind of particles go through simple diffusion?
not charged (nonpolar) particles
what kind of particles go through facilitated diffusion?
small charged (polar) particles can still go through passive transport with the use of channels
what is a specific example of facilitated diffusion?
potassium channels
what kind of particles go through osmosis?
water
what are the three types of solutions where osmosis can occur?
hypertonic, hypotonic, and isotonic
which is the solution that has less solutes hence causing water the move into the tissue?
hypotonic
which is the solution that has more solutes hence causing water to move out of the tissue?
hypertonic
which solution has same amount of solute as water and hence water transports in and out of the tissue at equal rates?
isotonic
how is active transport defined as?
movement of particles against the concentration gradient
what does active transportation require?
ATP (energy)
what are two types of active transport?
vesicle transports and protein pumps
what aspect of membranes allow for vesicle transport to be possible?
its fluidity
what is endocytosis?
when vesicles transport materials inside the cell
what is exocytosis?
when vesicles transport materials to the outside of the cell
what organelle creates vesicles to secret materials?
the Golgi Apparatus
how do protein pumps work?
chemicals and ATP bind against one side of the pump and the ATP splits, releasing energy. This causes the pump to open and the chemical to move across the membrane
outline how a sodium-potassium pump works
- the pump recieves 3 Na molecules and an ATP
- the ATP transfers its P group to the pump, opening the pump and sending the ion into the cell
- 2 potassium ions then bond to the inside of the cell and with the release of the previously transferred P group the potassium ions get released outside of the cell
outline how sodium potassium channels work
- the gate is closed when the membrane charge is negative
- the gate opens only when the charge becomes positive
- when the gates are open the positive potassium ions squeeze through and go outside the cell making the inside of the cell more negative
- hence the gate closes again