Membrane Transport - Chapter 7 Flashcards
What macromolecules are involved in the fluid mosaic?
Peripheral proteins
Transmembrane proteins
Glycolipids
Glycoproteins
Role of cholesterol in fluidity
Acts as a buffer
Different effects at different temps
Body temp-restrains movement
Cool temps-maintains fluidity, prevents tight packing; useful for hibernation
Peripheral proteins
Not embedded in the lipid bilayer
Bound loosely
Found attached to the membrane
Transmembrane (integral) proteins
Penetrate the hydrophobic interior of the lipid bilayer
Span the entire thickness of the membrane
Glycolipids
Carbohydrate attached to a lipid
Glycoproteins
Carbohydrate attached to a protein
Receptor protein
Receive chemical messages from other cells in the body
~like a mailbox
Recognition protein
Identify the cell as a specific type
Search for foreign substances
Transport proteins
Aid in transport of substances through the membrane
~ usually transmembrane
Enzymatic proteins
Involved in modifying a substance through chemical reactions
Functions of membrane carbohydrates
Similar jobs as proteins
- recognition
- receptor
- attach to external brand proteins to help brace it together so the membrane isn’t floppy
Diffusion
The tendency of a substance to move from where they are high in concentration to where they are lower in concentration until it reaches equilibrium
Down a concentration gradient
Against a concentration gradient
Down: high–>low; passive
Against: low–>high; active
Osmosis
Passive transport of water down a concentration gradient across a selectively permeable membrane
Water always moves towards areas that are hypertonic
Isotonic
- in plant cells
- in animal cells
Having the same concentration, no net movement
- plants become flaccid
- animals favor
Hypertonic
- in plant cells
- in animal cells
External solution having more solute -plant cells plasmolyze
-animal cells crenate (shrivel)
Hypotonic
- in plant cells
- in animal cells
External solution has less solute
- plants favor to become turgid
- animals burst or lyse
Cyclosis
Plants in a hypotonic solution
The organelles can be seen streaming around the central vacuole
Uniport
Transports one substance in one direction
Against concentration gradient
Symport/cotransport
Transfers 2 substances together; one against gradient and one down a gradient
Antiport/counter-transport
Transports two substances in opposite directions; both against their gradient
Facilitated transport
Passive transport
Primary active transport
When ATP is used directly to transport a substance
-uniport and antiport
Secondary active transport
Indirect use of energy
-cotransport
