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
channel proteins are
carrier proteins
hydrophilic channel (when open)
bind themselves to molecules they assist
membrane is _____ permeable
selectively
___ ______ allow passage of ions.
ion channels
gated channels:
open or close in response to stimulus message
CONDITIONS TO DETERMINE MOVEMENT
relative concentration on _____ side on membrane
______ differences across membrane
gated channels either ____ or _____
either
voltage
open or closed
cytoplasm of the cell is an ______ solution
water is a _______
dissolved substances are ______
aqueous
solvent
solute
osmosis is
the nest diffusion of water across a membrane toward a higher solute concentration
hypertonic have a _____ solute concentration
hypotonic has a ____ solute concentration
higher
lower
when two solutions have the same osmotic concentration, the solutions are ______
isotonic
aquaporins _______ osmosis
facilitate
OSMOTIC PRESSURE
_____ is needed to stop osmotic flow
cells in a hypotonic solution gain water, causing it to _____ and creating _____
if the membrane is strong enough, the cell ____ _____ osmotic pressure
if membrane is weak, cell may _____
animal cells must be in ______ environments
force swell, pressure counter balances burst isotonic
some cells use ____, where water is ejected through contractile vacuoles
___ ______ involves keeping cells isotonic with their environment
marine organisms adjust internal ______ to match sea water
terrestrial animals ______ isotonic fluid
plant cells use _____ _____ to push the cell membrane against the cel wall to keep it rigid
execution isosmotic regulation concentration circulate turgor pressure
___ is used directly or indirectly to fuel active transport
moves substances from ____ to ____ concentration
requires the use of…
ATP
low to high
highly selective carrier proteins
types of carrier proteins
uniporters (move one molecule)
symporters (move two molecules in the same direction)
antiporters (move two molecules in opposite directions)
the ____-_____ _____ directly uses ATP for active transport
sodium-potassium pump
the sodium potassium pump moves __ Na+ out of the cell and __ K+ into the cell.
goes _____ the concentration gradient
ATP energy is used to change the ______ of the carrier protein
affinity of the carrier protein for either Na+ or K+ changes so the ____ can be carried across the membrane
3,2
against
confirmation
ions
COUPLED TRANSPORT
uses ATP _______
uses energy released when a molecule moves by _______ to supply energy to active transport another molecule
_______ is used
Na+ support captures the energy from Na+ diffusion to move ______ against a concentration gradient
indirectly
diffusion
symporter
glucose
BULK TRANSPORT 1. endocytosis movement of \_\_\_\_\_ in the cell phagocytosis cells take in \_\_\_\_\_\_\_ \_\_\_\_ pinocytosis cells take in only \_\_\_\_\_\_ receptor-meditated endocytosis is specific molecules are taken in after they \_\_\_\_ to a receptor 2. exocytosis movement of substances \_\_\_\_ of a cell \_\_\_\_\_\_ energy
substances
particulate matter
fluid
bind
out
requires
the membranes main job is to _____ ____ _______ and keep the cell ________.
it is selectively ________.
some marterial can _____ enter and exit the cell, others can’t.
define cell boarders, functional
permeable
freely
membrane _____ the nature of its interaction with its environment.
cell has _______ that allow other cells to recognize it. this plays a roll in self vs nonself ________.
inter gram proteins act as _______ processing activators.
HIV is…
determines
markers, distinction
intercellular
human immunodeficiency virus
the plasma membrane was found in _____
chemical components were found in ____
principle components were ____ and ______
1890
1915
lipids, proteins
in ____ davson and danielli proposed the plasma membrane structure
first model that was ______ accepted
based on ____-_____ appearance
theorized structure resembled a ________
_____ were the bread, _____ were the filling
plasma membrane ranges from _-__ mm
phospholipids are made up of _____, two ____ _____ and a ______ linked head group
cholesterol is four fused ______ rings. they’re situated beside __________.
protein make up __%, lipids make up __% and carbs make up __%
amphiphilic means-
plasma membrane includes…
1935 widely rail road sandwich proteins, lipids 5,10 glycerol, fatty acids, phosphate carbon phospholipids 50, 40, 10 nonpolar, dual-loving phospholipids, cholesterol, proteins, and carbohydrates
integral proteins ____ completely into the membrane structure.
peripheral proteins are on the _____ and _____ surface, and attach to integral proteins and phospholipids.
both may serve as ______
integrate
exterior and interior
enzymes
carbs are the _____ major plasma membrane component
bound to ______ or ______.
third
proteins, lipids
component phospholipid cholesterol integrins peripheral proteins carbohydrates
location main membrane fabric attached between phospholipids/layers embedded in phospholipid layer bilayers inner and outer surface attached to proteins outside membrane layer
plasma membranes are ___________
asymmetric
factors that affect diffusion
- extent of the ______ gradient
- _____of molecules diffusing
- higher ________ increases energy and movement
- as ______ increases, _____ rate decreases
- nonpolar ______ material from ass through membrane easier
- increased ______ ______ increases the diffusion rate
- greater the _______ a surface must travel, the slower the diffusion rate
- concentration
- mass
- temperature
- density
- soluble
- surface area
- distance
tonicity is how an ______ solution can change a cells volume by affecting osmosis
extracellular
plasmolycsis is when the cell membrane _______ from the cell wall and constricts the cytoplasm
detaches
