7 Flashcards
(19 cards)
What is passive transport?
The movement of molecules across a membrane without the use of energy.
Define simple diffusion.
The spreading of molecules across a membrane until equilibrium is reached.
What is equilibrium in the context of diffusion?
A state where molecules are equally concentrated on both sides of the membrane.
In simple diffusion, molecules move _______ a concentration gradient.
down
Give an example of molecules that undergo simple diffusion.
O2 and C2 and other small, nonpolar molecules.
What is facilitated diffusion?
A process where a transport protein helps to facilitate the diffusion of molecules that normally couldn’t pass through the cell membrane.
What role do transport proteins play in facilitated diffusion?
They can act as a channel or a carrier.
In facilitated diffusion, molecules move _______ a concentration gradient.
down
Provide an example of molecules that undergo facilitated diffusion.
Polar molecules like glucose (C6H12O6) and ions like calcium (Ca+2).
Define osmosis.
The simple diffusion of water across the cell membrane.
In osmosis, water molecules move _______ a concentration gradient.
down
What does high water concentration indicate?
Low solute concentration.
What does low water concentration indicate?
High solute concentration.
In hypertonic solutions, water concentration is _______ than the cell’s cytoplasm.
higher
What happens to a cell in a hypertonic solution?
The cell shrinks.
In hypotonic solutions, water concentration is _______ than the cell’s cytoplasm.
lower
What happens to a cell in a hypotonic solution?
The cell swells.
In isotonic solutions, water concentration is _______ to the cell’s cytoplasm.
identical
What happens to a cell in an isotonic solution?
The cell stays the same.
