Membranes Flashcards
What are cell membranes comprised of?
They are a sea of phospholipids in which float proteins and carbohydrates
Name 6 membrane properties
- Must be impermeable
- Allow communication
- Expand and change shape
- Import/export specific molecules/ions
- Interact with and recognized the outside world
- Protect the cell from elements
What is the default shape of a membrane and how can you change this?
Circular, and the cytoskeleton can change the shape
How can you change membrane fluidity? list two ways
- Having more unsaturated hydrocarbon tails: this will increase fluidity
- Incorporate cholesterol: this decreases membrane fluidity
Where does phospholipid synthesis occur?
sER on the cytosolic side of the bilayer, will then pinch off into vesicles and go to the golgi
What is the role of the golgi apparatus in phospholipid synthesis?
It creates an asymmetrical/heterogeneic membrane
Name 5 types of membrane proteins
- Transporters
- Receptors
- Enzymes
- Linkers between interior and exterior of cell
- Anchors of membranes to cytoskeleton or extracellular matrix
Name the two types of membrane transport proteins. Define them
- Transporters: bind molecules and undergo transformational change.
2.Channels: form aq. pores that allow solutes to quickly cross
SOLUTE SPECIFIC
What two things are solute transport dependent on?
Osmosis and diffusion
Define membrane potential
the difference of voltage across a membrane
Define passive vs active transport
Passive: facilitated diffusion. No energy expenditure
Active: Flows against own gradient
What are the two types of active transport? define
Primary: ATP is used to drive the transport
Secondary: electrochemical gradient of one analyte is used to drive the movement of another
What are the three types of transporters? Define
-Symporter: moves 2 or more molecules in the same direction
-Antiporter: moves 2 or more molecules in different directions
-Uniporter: moves 1 molecule in one direction
* these can either be active OR passive
