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what is the cell membrane made out of
proteins, lipids, and cholesterol
how do membranes orient themselves in a double membrane area
the polar end is on the aqeous inside/intracellular space and they’re also on the outsie/extracellular fluid
what does the phosphate head of the phospholipid contain
a phosphate group that are in an ionized/charged state
what kind of phospholipid does a bulky head have
a single-layer lipid sphere with a polar function exterior and fatty acid interior
what kind of phospholipid does a less bulky head have
micelle
a double layer/lipid bilayer sphere: where the outermost layer faces the extracellular fluid meanwhile the interior=orientated so the phosphate heads face the inner hole/like a donut so water can be in the empty pocket and the fatty acid tails are facing each other
true or false, phospholipids and cholesterol are both ampiphathic
true
(have a polar and nonpolar side)
cell membrane needs a section to interact and exclude water
why must membranes not be stiff
so they can grow and heal
what is the main component that distributes membrane fluidity
cholesterol
what specifically makes the cholesterol support fluidity
the kink in one of the fatty acid tails(caused by a double bond of carbon/unsatruation)
which prevents tight rigid packing
how does cholesterol avoid stiffness
the bulkiness of rings help prevent lipid packing/ a solid membrane
where is cholesterol on the phospholipid
in the fatty acid chains
general info about transporter proteins
embedded in the phospholipid bilayer, allows material to pass from one side of the membrane to another
info abt receptor proteins
chemical signals + transit that signal to cells interior through signal transduction pathways
general info about enzymes
catalyze chemical reactions with substrate + give rise to product
anchor proteins
important for cell-cell interactions/proteins that need to be tethered to a cell in extra/intra cell space
which proteins are integral proteins
transporter, receptor, enzyme, and anchor proteins
how does the plasma membrane help with homeostasis
it keepts things stable by regulating which elements come in and out of the cell
what is the fluid mosaic
the phospholipid molecules vibrate, move around, and exchange places and they’re in the plasma membrances of plants+ animal cells
true or false, proteins do not have charges in the phospholipid bilayer
false, they have hydrophilic and hydrophobic areas so some aprts are charged
membranes
large nonpolar span limiting what passes through them
small nonpolar elements can pass through them
what are the functions of membranes
to keep inside diff from the outside(makes a concentration gradient)
be selectively permeable
let proteins hang out + do whatever
create a boundaries
in the presence of integral peripheral proterins/enzymes, the site of chemical reactions
cell recognition (elements of extracellular enviro )
what is simple diffusion
moving from areas of high to low concentration w/o protein support
ex: small nonpolar elements
uses lipids, energy from concentration gradient, can’t saturate
what is facillitated diffusion
going from areas of high to low concentration with the help of transport proteins/channels/carriers
ex: for polar charged molecules like water, amino acid, sugar
uses proteins, energy from the concentration gradient, can saturate
what is active transport and what are the two types
goes from low to high transport and uses ATP
primary and secondary active transport
uses proteins, energy from ATP hydrolysis/diff concentration gradient, can saturate
what is primary active transport
uses energy-carrying molecules like ATP/GTP to give protein energy to pump a molecule/ion against its concentration gradient
what is secondary active transport
uses existing concentration gradient
one thing goes from area of high to low concentration, allowing the other thing to go from low to high
ex: like wind opening a door allowing smth to sneak inside too
true or false, nonpolar tails=smaller than polar regions and easier to get through
false
if a small nonpolar molecule is sneaking into the phospholipid membrane what will it be able to sneak past
the hydrophilic heads and nonpolar tails
what can polar molecules sneak through
the hydrophilic heads but not the nonpolar tails w/o help
how does cholesterol regulate the membrane in low and high temps
it increases fluidity at low temps to prevent freezing
it decreases fluidity at high temps to prevent phospholipids from dissembling and letting things through
what do glycoproteins do
sugar group involved in immune recognition
what do transport proteins do
channels, pumps, carriers that let things that can’t norm pass through pass through the membrane
proteins can also be channels, carries, etc, proteins=the molecules that usher in do things in our body
what do proteins in cell-cell junctions do
bind cells tightly together as exemplified in gap junctions and tight junctions
what do cell-cell recognition proteins do
identify a cell as part of the same individual or as a foreign, facilitate cell-cell linking, binds cells to extracelllular matrix/ECM and link ECM to cytoskeleton
