Cell Membranes Flashcards
Active Transport
Movement of substances across membranes against their concentration gradient, requiring the use of energy in the form of ATP. Active transport usually involves the use of transport proteins.
ATP
Molecule used to store energy temporarily in organisms.
Carrier Protein
A protein found in membranes, which is capable of carrying a specific molecule or ion through the membrane by active transport or large molecules by facilitated diffusion.
Cell Signaling
Processes that lead to communication and coordination between cells. Hormones binding to their receptors on the cell surface membrane are an example.
Chanel Protein
A protein pore that spans a membrane, through which very small ions/charged molecules may pass by facilitated diffusion.
Concentration Gradient
The difference in concentration of a substance between two regions.
Crenation
State of animal cells when they have been immersed in a solution of lower water potential and have lost water by osmosis. They become shrivelled.
Diffusion
The net movement of molecules or ions in a gas or liquid from an area of high concentration to an area where they are less concentrated until dynamic equilibrium occurs.
Diffusion Gradient
The gradient in molecular concentration (the difference in concentrations) that allows diffusion to occur.
Endocytosis
The process of taking materials into a cell by surrounding them with part of the plasma membrane, which then pinches off to form a vesicle inside the cell. This is an active process requiring ATP.
Exocytosis
The process of removing materials from the cell by fusing vesicles containing the material with the plasma membrane (cell surface membrane).
Facilitated Diffusion
The passive movement of molecules across membranes down their concentration gradient, which is aided by transport (carrier) protein molecules. No metabolic energy is required.
