7.3 Flashcards
What is osmosis?
The diffusion of water across a selectively permeable membrane. During this process, water will move across a membrane until the concentration of solute is the same on both sides.
What state are Particles in solids, liquids, and gasses in?
constant random motion.
What is Diffusion?
The net movement of particles from an area of high concentration to an area of lower concentration.
What is dynamic equilibrium?
When diffusion occurs over a long enough time, concentrations will become uniform, and the solution will reach this state. Molecules continue to move, but the overall concentration remains the same.
What is Facilitated diffusion?
It uses transport proteins to move ions and small molecules across the plasma membrane.
What is a process that requires no additional energy?
Passive transport
What are isotonic, hypertonic, and hypotonic solutions?
An isotonic solution has the same concentration of water and solutes as the cytoplasm of the cell. Water still moves through the membrane, but it enters and leaves at the same rate.
A hypotonic solution has a lower concentration of solutes than the cytoplasm of the cell.
The net movement of water is into the cell. As water moves into the cell, pressure increases.
Animal cells can burst when placed in extremely hypotonic solutions.
A hypertonic solution has a higher concentration of solutes than the cytoplasm of the cell.
The net movement of water is out of the cell. As water moves out of the cell, pressure decreases. Hypertonic solutions cause wilting in plants.
How does active transport occur?
With the aid of carrier/transport proteins, often called pumps.
Where are Na+/K+ ATPase pumps found?
In the plasma membrane of animal cells.
What is coupled transport?
A process in which sugars can pair with Na+ ions and enter the cell through a membrane protein called a coupled channel. Allow sugars to enter through facilitated diffusion – saving energy
What is Endocytosis?
The process by which a cell surrounds an object in the outside environment in a portion of the plasma membrane.
What is Exocytosis?
The excretion of materials at the plasma membrane.
What is the diffusion of water across a selectively permeable membrane?
Osmosis
Why is additional energy not required for diffusion?
Because the particles are already in motion.
What is the net movement of particles from an area of high concentration to an area of lower concentration?
Diffusion.
When diffusion occurs over a long enough time, concentrations will become uniform, and the solution will reach this state. Molecules continue to move, but the overall concentration remains the same.
Dynamic equilibrium
What process uses transport proteins to move ions and small molecules across the plasma membrane?
Facilitated diffusion
What are two examples of passive transport?
Diffusion and facilitated diffusion
What is the movement of particles across the cell membrane, against the concentration gradient, and requires energy called?
Active transport.
What is active transport?
The movement of particles across the cell membrane, against the concentration gradient, and requires energy.
