Biology Membranes and Cell Transport
Membrane proteins assist ions and polar molecules across membranes down their concentration gradient in
facilitated diffusion.
What is the process whereby an ion, an atom, or a molecule crosses a membrane without using energy?
passive transport
What causes diffusion of a substance?
random molecular motion
What type of membrane transport is shown in the picture and lacks a carrier molecule? Area of high concentration to area of low concentration without any help
simple diffusion
What describes osmosis?
simple diffusion of water
When the gradient of a particular solute across a membrane has dissipated due to diffusion, what can be said about the solutions on either side of the membrane?
The concentrations of the solutions are in equilibrium.
A substance is moved from an area where its concentration is low to an area where its concentration is high with the expenditure of energy in
active transport
What type of membrane transport is shown in the picture and requires ATP and a carrier molecule?
active transport
What type of membrane transport requires energy (ATP) and transport proteins?
active transport
In diffusion, a substance moves
by passive transport to a region where the substance is less concentrated.
In a membrane transport process called ______, a cell transports large molecules to the cell membrane in vesicles and releases them to the outside of the cell.
exocytosis
What type of membrane transport is shown in the picture and requires a carrier molecule, but not ATP?
facilitated diffusion
Select all of the following that describe active transport.
-a substance moves against its concentration gradient -transport proteins are required -energy is required
Select all of the following that are occurring in the image. (Tea)
-diffusion -random molecular motion
If an equal amount of water enters and exits a human red blood cell, then the cell's interior is ______ to the cell's exterior.
isotonic
What describes simple diffusion?
A substance moves down its concentration gradient.
The spontaneous movement of a substance from a region where it is more concentrated to a region where it is less concentrated is called
diffusion.
What process is shown in the picture, reading it from the top panel to the bottom panel?
endocytosis
In passive transport, no ___________________ is spent to move a substance across a membrane.
energy
At equilibrium, molecules continue to move back and forth between areas of solution at ______ rates, creating ______ concentrations throughout a solution.
equal; equal
If a solution has a higher solute concentration than a cell, then the solution is ______ compared to the cell.
hypertonic
If more water is exiting a human red blood cell than entering it, then the cell is in a(n) ______ solution.
hypertonic
If a solution has a lower solute concentration than the interior of a cell, then the solution is ______ compared to the cell interior.
hypotonic
If more water is entering a human red blood cell than exiting it, then the cell is surrounded by a(n) ______ solution.
hypotonic
Endocytosis is the process of transporting substances
into the cell using vesicles.
In an isotonic solution, the solute concentration
is equal between two neighboring areas.
facilitated diffusion
movement of solutes from high to low concentration with a transport protein
simple diffusion (passive transport)
movement of solutes from high to low concentration without a transport protein
active transport
movement of solutes from low to high concentration with a transport protein
osmosis
movement of water from areas of high water concentration (low solute concentration) to areas of low water concentration (high solute concentration)
The image shows the diffusion of water across a membrane, which is called
osmosis
The diffusion of water across a membrane down its own concentration gradient and toward the region with a higher solute concentration is called
osmosis.
Exocytosis is the process of transporting substances
out of the cell using vesicles.
