Ex. 4 Flashcards
All prokaryotic and eukaryotic cells are separated from the external
environment by a
Cell membrane
scientists discovered that the cell membrane is s____, meaning that
some molecules are able to cross the cell membrane while others are prevented from crossing the membrane.
selectively permeable,
defined as the movement of
solute molecules from an area of higher concentration to an area of lower
concentration
Diffusion
water moves across the cell membrane by___ , a membrane process in which water molecules move across the membrane in response to a concentration gradient
osmosis
are lipid–protein assemblies in which the components are held together in a thin sheet by non-covalent bonds
Membranes
are insoluble in water
but dissolve readily in organic solvents.
Lipid molecules
It is the shape and ___ nature of the
lipid molecules that cause them to form bilayers spontaneously in aqueous solution.
amphipathic nature
has been regarded as the universal basis for the cellmembrane structure
The lipid bilayer
the ___ is an impermeable barrier that prevents the diffusion of watersoluble (hydrophilic) solutes.
hydrophobic core
The simple barrier function is modulated by the presence of ____that mediate the transport of specific molecules
across this otherwise impermeable bilayer
membrane proteins
Lipid bilayer exhibits two important properties:1
- Hydrophobic core
- Stability
The bilayer structure is maintained by
hydrophobic and van der Waals
interactions between the lipid chains.
has a strong, obnoxious odor and the fumes are somewhat irritating.
Adequate ventilation is required
Iso-amyl alcohol
Red onion cells contain a high concentration of the red pigment, ___
anthocyanin.
the coming together of 2 different cells, organelles or membranes into one cohesive unit
Fusion
