1.4 - Membrane transport Flashcards
Define diffusion.
Passive movement of molecules such as oxygen, CO2 or glucose from a region of high to low concentration
What does passive mean?
Not requiring energy
Define osmosis.
Passive diffusion of water molecules from a region of higher to lower concentration of water molecules
What are two similarities of osmosis and diffusion?
- Both passive transport
- Both movement of molecules down/against concentration gradient
What is simple diffusion?
Movement of molecules across a semi-permeable membrane until homeostasis is met
What is facilitated diffusion?
The movement of polar molecules/ions across a lipid bilayer with the help of a protein
What do simple + facilitated diffusion not require?
Energy
What is exocytosis?
Exo=exit
The fusion of a vesicle with a plasma membrane
What is endocytosis?
Endo=enter
A cell taking in molecules by forming new vesicles from the plasma membrane
What allows endo + exocytosis to work?
The membrane being in a fluid mosaic - vesicles being able to break away/join the main membrane in any position
Define metabolism.
Describes the totality of chemical processes that occur within a living organism in order to maintain life
