membranes Flashcards
what is the usual diameter for human cells
10-15 um in diameter
what is the diameter of human egg cells
100 um
axons can be up to ___m long
1
what is the diameter of a human red blood cell
7-8 um
what are two reasons cells are so small
SA to volume ratio would make it
-inefficient for nourishment/ waste removal
-time required for diffusion would be too long
when one side doubles in length of a cell, the surface area increses _____-fold, and the volume increases ____-fold
4
8
breakdown in % of
phospholipids
cholesterol
glycolipids
protein
in a cell membrane
phospholipids: 75%
cholesterol: 20%
glycolipids: 5%
protein: 2%
function of phospholipids, cholesterol, glycolipids, and protein in a cell membrane
phospholipids: billayer properties
cholesterol: stiffness
glycolipids: cell non-self recognition
protein: 50% of weight (only 2% composition)
what are transmembrane proteins
completely go through membrane into the cytoplasm
what are the rafts made of that proteins on the membrane are clustered on
cholesterol
what type of transmembrane protein is this:
binds to chemical messengers sent by other cells
receptor
what type of transmembrane protein is this:
breaks down a chemical messenger and terminates its effect
enzyme
what type of transmembrane protein is this:
constantly open and allowed solutes to pass in and out of the cell
channel
what type of transmembrane protein is this:
opens and closes to allow solutes through but only at certain times
gated channel
what type of transmembrane protein is this:
glycoprotein distinguishing the body’s own cells from foreign cells
cell identity marker
what type of transmembrane protein is this:
molecule that binds one cell to another
cell adhesion molecule
where does the second messenger come from
a receptor in the cytoplasm that received its messenger from a different messenger in the extracellular environment
what is the glycocalyx
the fuzzy coat external to the plasma membrane
glycocalyx is unique in everyone except
identical twins
what is the function of the glycocalyx
an identification tag that enables the body to distinguish its own healthy cells from t
what are microvilli and what is their function
projections on a cell membrane that increase surface area
what is the boarder that is composed of microvilli called
the brush boarder
what are cilia and what is their size relative to microvilli
projections on a cell membrane that are larger than microvilli
what is the function of cilia (2)
to help the cell move
in the lungs, dust gets caught in them
what are flagella
what do they do
what are the only cells theyre found in
projections on cell membrane
move a cell
sperm
most cells have 1 _______ cilia, and its called the
nonmotile
primary cilium
what are pseudopods
what are their function (3)
membrane extensions
engulf/ move/ interact with different cells
what 2 types of transport require energy input
active transport
bulk transport
what 3 types of cell transport do not require energy input
osmosis
diffusion
facilitated diffusion
is filtration active or passive
how does it work
passive
particles driven though membrane with physical pressure
what is facilitated diffusion
does it go with or against the gradient
does it require energy input
diffusion with the help of a protein on the cell membrane
with
no
what do cells look like when theyre in a _____ solution
hypertonic
hypotonic
shriveled
inflated
how do uniport carriers work
channel with one thing that moves though it
how do symport channels work
2 different molecules move though it in the same direction
how do anti port channels work
moves 2 different things at the same time in OPPOSITE directions
how does secondary active transport work
when one thing can move up its concentration gradient because its coupled with something else moving down the gradient
(both going into the cell)
what is vesicular transport
what does it move
does it require ATP
moves partivels by creating a vesicle around them and motor proteins are involved in this process
large/ multiple particles and fluid droplets
yes
brief description of these types of endocytosis:
phagocytosis:
pinocytosis:
cell “eating”
cell “drinking”
receptor mediated endocytosis in 3 steps
what is the protein involved with this process
- molecules bind to receptors on membrane and receptors cluster together
- membrane sinks inward and creates a pit
- pit separates from membrane and becomes its own vesicle
clathrin
what is transcytosis
transporting materials by capturing it on one side and releasing it on the other
what are 2 functions of exocytosis
secreting material
replacement of plasma membrane removed ny endocytosis
what are peripheral proteins in the cell membrane
do not protrude into the phospholipid layer, but adhere to either the inner or outer face of the membrane
