Membrane Transport PPT Flashcards
all materials must pass through the ___ to enter or exit the cell
plasma membrane
plasma membrane is ___
semi-permeable
List 3 ways to transport molecules.
- diffusion through the membrane
- protein transport
- vesicular transport
Transport mechanisms are categorized as either ___ or ___ processes.
passive,
active
Molecules are in ___ random motion.
constant
Molecules are more likely to interact when there is a ___ concentration.
high
difference in the number of molecules between two regions
concentration gradient
Which way will molecules move with a gradient?
from higher to lower concentration
What is molecule movement driven by?
energy in each molecule
the net movement of molecules down a concentration gradient; not affected by the concentration gradient of other molecules
diffusion
List 4 factors that affect the rate of diffusion.
- steepness of concentration gradient
- temperature
- molecule siz
- nature (wind speed/ water currents)
a result of diffusion; the energy of the molecules becomes equal; the molecules continue to move randomly but there is an equal amount of movement in both direction
equilibrium
What can diffuse through the plasma membrane?
small, non-polar molecules;
lipids
What is the most common substance to pass through the plasma membrane?
water
Water can pass through specific water channels in the plasma membrane called ___.
aquaporins
name for water diffusion
osmosis
occurs when water concentration is different on the two sides of a membrane
osmosis
Osmosis is dependent on the concentration of other molecules dissolved in the solution called ___.
solutes
more solutes = less ___
water
the concentration of all molecules dissolved in a solution
osmolarity
ability of a solution to alter the cell’s water volume
tonicity
solution with a higher solute concentration (less water)
hypertonic
solution with a lower solute concentration (more water)
hypotonic
when two solutions have the same solute concentration
isotonic
