chapter 5 structure and function plasma membranes Flashcards
MEMBRANE STRUCTURE highly \_\_\_\_\_\_\_\_\_ \_\_\_\_\_\_\_\_ are arranged in a bilayer globular \_\_\_\_\_\_ insert into the lipid bilayer fluid mosaic model-
organized
phospholipids
proteins
mosaic of proteins floating in/on the fluid lipid bilayer
4 components of cell membrane
phospholipid bilayer
transmembrane protein
interior protein network
cell surface markers
the fluid mosaic model of the plasma membrane describes the plasma membrane as a fluid combination of _______, ______, and _______.
______ attach to the lipids and proteins extend from the outward facing surface of the membrane
phospholipids, cholesterol, and proteins
carbohydrates
phospholipid structure consists of
glycerol (a 3-carbon polyalcohol)
2 fatty acids attached to the glycerol
a phosphate group attached to the glycerol
BILAYER
fatty acids are on the ______
phosphate groups are on ____ surfaces.
inside
both
the phospholipid bilayer is composed of a ______ head and two _____ tails.
the ____ consists of a phosphate-containing group attached to a _____ molecule.
the tails contain either _____ or an ______ fatty acid.
their hydrophobic tails face ______.
hydrophilic, hydrophobic
head, glycerol
saturated, unsaturated
inward
membrane proteins
tansporters enzymes cell-surface identity markers cell-surface receptor cell-to- cell adhesion proteins attachments the the cytoskeleton
mom-polar regions of the protein are embedded in the ______ of the bilayer
poplar regions of the protein profited from ____ sides of the bilayer
interior
both
the transmembrane domain _____ the lipid bilayer
hydrophobic amino acids arrange into a ______
spans
helice
interfere membrane proteins may have one or more ____-____ that span the membrane, or they may have ___-____ that span the membrane
alpha-helices
beta-sheets
HIV binds to the ___ receptor, a glycoprotein in the surfaces of t-cells
CD4
PASSIVE TRANSPORT
movement of ______ through a membrane
no _____ required
molecules move in response to a ______ gradient
diffusion is…
will continue until the _____ is same in all regions.
molecules energy concentration movement of molecules from high to low concentration same
major barrier to crossing a biological membrane is the hydrophobic interior that _____ polar molecules.
_______ molecules will move until the concentration is ______ on both sides
limited permeability to _____ polar molecules and ions
repels
nonpolar, equal
larger
diffusion through a permeable membrane moves a substance from an area of ____ concentration down the concentration ______.
high, gradient
______ transport moved substances down the concentration gradients. they may pass the plasma membrane with aid of…
facilitated, channel proteins
major barrier of the plasma membrane ____ ____, thst repels _____ molecules, but not _____ molecules
hydrophobic interior, polar, nonpolar
nonpolar molecules will move until the concentration is ____ on both sides.
limited permeability for _____ polar molecules, and very limited permeability for ____ polar molecules and atoms
equal
small, larger
molecules that can’t pass the membrane easily may enter through ___
protein so