unit 2 exam phospholipids

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 that recieve a signal and initiate a response

general info about enzymes

catalyze chemical reactions with substrate + give rise to product

anchor proteins

proteins that need to be tethered to a cell

help with cell structure

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

enabling cells to distinguish between themselves and foreign cells, and also for cell adhesion and interaction