Membrane Transport Flashcards
Polar molecules
Such as sugars do not cross the membrane easily
Passive transport
Is a diffusion of a substance across a membrane with no energy investment
Diffusion
Tendency for molecules to spread out evenly into the available space
Dynamic equilibrium
As many molecules cross the membrane in one direction as in the other
At higher temperature the diffusion rate is
Greater
At a given temperature smaller molecules diffuse faster ?
True
Osmosis
Is diffusion of water across a selectively permeable membrane
How does water diffuses across a membrane?
from the region of lower solute concentration to region of higher solute concentration until the solute concentration is equal on both sides
Hydrophobic (NONPOLAR) molecules
Can dissolve in lipid bilayer and pass through the membrane rapidly
Tonicity
Is the ability of a surrounding solution to cause a cell to gain or lose water
Isotonic solution
Solute concentration is the same as the inside the cell; no net water movement across the plasma membrane.
Hypertonic solution
Solute concentration is greater than that inside the cell; cell loses water
Hypotonic solution
Solute concentration is less than That inside the cell, cell gains water
Plasmolysis
In a hypertonic environment plant cells lose water, eventually the membrane pulls away from the wall a usually lethal effect
Active transport requires energy in ur form of
ATP
How is active transport performed ?
By specific proteins embedded in the membranes
Types of transport
Uniform
Symport
Antiport