Cell Physiology - Membrane Transport Flashcards
What are the 3 components of the plasma membrane?
- Membrane Lipids
- Membrane Proteins
- Membrane Carbohydrates
What are the 3 components of a lipid?
- Phospholipid
- Cholesterol
- Glycolipids
What is the function of cholesterol in the plasma membrane?
- strengthens membrane
- stabilizes membrane against temperature extremes
Glycolipids help to form the ____, which is the “coating of sugar” on cell’s surface.
Glycocalyx
____ proteins are embedded within and extend across the phospholipid bilayer.
Integral
____ proteins are loosely attached to the external or interior surfaces of the membrane. (Not embedded in lipid bilayer)
Peripheral
The 2 types of passive processes of membrane transport are ____ and ____.
- diffusion
- osmosis
Passive membrane transport depends on substances moving ____ the concentration gradient.
down
High to low concentration
What 3 things determine the rate of transport in diffusion?
- “steepness” of concentration gradient
- Temperature (more movement with higher temp)
- Molecular size
In ____ diffusion, small nonpolar solutes pass between phospholipid molecules.
Simple
True or False: In simple diffusion, molecules continue to move as long as the concentration gradient exists.
TRUE
In ___ diffusion, small charged or polar solutes require assistance from plasma membrane proteins.
Facilitated
Channel-mediated diffusion is important in normal function of ____ and ___ cells
muscle, nerve
How are small polar molecules transported across plasma membrane in carrier-mediated diffusion?
Molecule binds to carrier protein, causing it to change shape and move molecule across membrane.
What are the 2 ways water can cross the membrane in osmosis?
- Slips between molecules of phopholipid bilayer
2. Moves thru integral protein water channels (aquaporins)
When does osmosis stop?
when there is equal concentration of water inside and outside of the cell (Equilibrium)
_____ transport uses energy directly from breakdown of ATP to move solute across membrane.
Primary active
What are the 2 types of primary active tranport?
- Ion pumps
- Sodium-potassium pump
Ca2+ pumps in the membrane of erythrocytes function to remove intracellular Ca2+ to prevent _______ from the accumulated calcium.
cell rigidity
How are ions exchanged in the sodium-potassium pump?
2K+ move in while 3Na+ move out
Na/K Pump continuously exports Na+ out and moves K+ in as long as … ?
as long as there is ATP.
What are the 2 types of secondary active transport?
- Symport (substances moved in same direction)
- Antiport (substances move in opposite direction)
In what active process does a cell engulf a large particle that is external to the cell?
Phagocytosis
“cellular eating”
What active process involves the internalization of droplets of interstitial fluid containing dissolved molecules?
Pinocytosis
“cellular drinking”
What active process uses receptors on the plasma membrane to bind molecules within interstitial fluid and bring the molecules into the cell?
Receptor-mediated endocytosis
In ____ transport, energy is used from a 2nd substance moving down its gradient in order to move substance across gradient.
Secondary active
