cell membranes and transport Flashcards
why sis the phospolipid bilayer good
allows lipid soluble molecules across but not water soluble.
what is the role of extrinsic proteins
structural support and recognition sites by identifying cells and receptor sites for hormone attachment.
role of intrinsic proteins
carriers for water soluble molecules
-other allow active trasnport of ions by forming channles
the carbohydrate layer around the membrane is called the glycocalyx what roles does the molecules within this have
hormone receptors and cell to cell recognition
what moleules are transported by simple diffusion
non-opolar small e.g 02 and c02 or lipid soluble molecules.
what is the ficks law equation
conc x surface area /thickness of membrane
what is facilitated diffusion
reuires channel proteins for ions or carrier proteins for large polar molecules e.g glucose.
protein molecules are filled with water so charged molecules can pass.
active trasnport
uses protein carrier molecules or a portein pump. Requires eergy to change chape of carrier molecule.large no . of ATP/mitochondria e. sodium/potassium pump in nervous system.
pinocytosis
small liquid molecules eengulfed by cell
endocytosis
bulk transport into cells for substances too large to pass and is engulfed by plasma membrane.
hypertonic
higher conc of solution than inside cell.
hypotonic
lower conc of solution than inside
what happens to hypertonic plnt cells
beome plasmolysed.
what happens tp hypotonic plant cells
become turgid
what is incipient plasmolysis
as a turgid cell loses water a point is reached where the cytoplasm no longer pushes he plasma membrane outward on the cell wall but is yet to be pulled away.
