(not all on exam) Cell Structure, Passive + Active Transport Flashcards
what do all cells do?
4 points
digest nutrients
excrete waste
synthesize chemicals
reproduce
what is
cell theory
3 points
all life composed of 1+ cells
cell is the smallest unit of life
cells can only come from other cells that already exist
common features of all cells
2 points (organelles)
cell membrane
cytoplasm
for most cells: presence of nucleus + DNA
classifying cells
prokaryote, eukaryote
depends on type of nucleus
what is
cytoplasm
everything within the cell membrane, excluding nucleus
includes liquid and organelles
what is
cytosol
liquid part inside cell
extension of nuclear membrane
rough ER
role of nucleus (if the mitochondria is the powerhouse then what is the nucleus)
directs cell activities
hereditary information is stored in…?
nucleus (chromosomes (DNA))
chromosomes store
genes
purpose of
genes
has instructions on making a specific protein
nuclear envelope is made of
2 lipid bilayers
what do plant cells have that animal cells don’t
chloroplast, central vacuole
present in animal cells and not plant cells
centrioles
nuclear membrane is made of
1 lipid bilayer
property of
nuclear membrane
selectively permeable
embedded in nuclear membrane
proteins, e.g. receptors, transporters
can cross the nuclear membrane freely
water + some gasses
where are ribosomes assembled
nucleolus
what is the nucleolus
physical characteristics + position
dense, dark region within the nucleus
function of nucleolus
assemble subunits of ribosomes from proteins + RNA
what is the nucleoplasm
semifluid interior portion of the nucleus
chromatin is
all DNA molecules and associated proteins in the nucleus
what is the endomembrane system
a group of interacting organelles b/w the nucleus and cell membrane
function of endomembrane system
make lipids, enzymes, proteins for use in cell
main organelles involved in endomembrane system
nucleus, ER, vesicles, golgi body
physical description of ER
lots of folds, shaped like flattened sacs + tubes
ER
endoplasmic reticulum
rough ER vs smooth ER
physical characteristics
rough ER covered in ribosomes
rough ER function
polypeptide chains are folded and take on their final complex structure (occurs in the interior of the ER)
function of ribosomes on rough ER
synthesize polypeptide chains
function of smooth ER
contains enzymes that produce lipids, break down material
example of material broken down by smooth ER
carbs, fatty acids, some drugs + poisons
what are vesicles
sac-like organelles
how do vesicles form
bud from other organelles or cell membrane
examples of vesicles
3 points
peroxisomes, vacuoles, lysosomes
organelles without a membrane
2 points
ribosome, centriole
purpose of transport vesicles
transport substances within a cell, or release them from the cell
secretory vesicles release substances, transport vesicles transport subs
golgi body physical characteristics
folded membrane, looks like a stack of flat sacs
function of golgi body
finalize peptide chains and lipids (from ER)
transport products using vesicles
how does the golgi body modify peptide chains + lipids
enzymes ! may attach phosphate groups or sugars, or cut chains
function of nucleus
protect + control access to DNA
where are lipids synthesized
smooth ER
organelle that generates ATP
mitochondria
function of chloroplast
produce sugars using light energy, CO2 and H2O
function of peroxisome
digest fatty acids and amino acids
function of vacuoles
isolate and dispose of waste, debris, toxic materials
function of lysosomes
carry out intracellular digestion and waste disposal using powerful digestive enzymes
which organelle inactivates toxins
peroxisome
which organelle aids in storage, and contains waste?
vacuole
purpose of vacuole unique to plants
maintain cell size and shape
function of centriole
produces microtubules for cytoskeleton, involved in cell division
function + composition of cilia
movement, made of microtubules
function of flagella
movement
properties of cell membrane
fluid, selectively permeable
name of structure of cell membrane
fluid mosaic model
cell membrane is made up of (molecule)
phospholipid molecules
cell membrane general structure
2 layers - bilayer
each layer of the cell membrane is called
a leaflet
intracellular
inside cell
something on the outside leaflet of the cell membrane is called
extracellular
a watery environment is
polar
molecule that forms membranes around all organelles
phospholipids
another name for intrinsic protein
integral protein
meaning of
transmembrane
spans the entire width of the bilayer
function of integral proteins
4 points
structural support, recognition, communication, transport
proteins responsible for recognition
within the cell membrane
e.g. in immune system
intrinsic proteins and glycoproteins
proteins responsible for communication
within the cell membrane
intrinsic and glycoproteins
proteins responsible for structural support
within the cell membrane (maintain shape)
integral and peripheral
peripheral provides support for other proteins
function of glycoproteins
attachment site for other cells
communication + recognition of proteins
proteins responsible for transport
within cell membrane
regulate molecules coming in and out of cell
integral proteins
types of proteins embedded in cell membrane
3 points
integral/intrinsic, glyco-, peripheral proteins
membrane protein classification
2 classes
polytopic, monotopic
definition of polytopic
faces both sides of the membrane
what is a glycoprotein
protein containing a sugar/carb bound to an amino acid
what is an integral protein
a protein embedded in the lipid bilary
typically transmembrane
single pass
polytopic protein
crosses membrane once
protein that crosses the cell membrane multiple times
multi-pass
monotopic
does not span entire bilayer, only on 1 leaflet/side
examples of transmembrane proteins
receptor, recognition, transport
attached to glycoproteins
carbohydrate groups
example of non transmembrane proteins
1
peripheral proteins
how are peripheral proteins bound to the membrane?
non-covalently
function of intracellular peripheral proteins
communication
function of extracellular periipheral proteins
structural support
receptor protein function
usu used as signalling molecules
how do receptor proteins work
ligand binds to binding site
example of recognition protein
glycoprotein - carb group helps identify cells
2 types of transport proteins
channel, carrier/pump
2 types of channel proteins
ungated/leak, gated
how do channel proteins work
no energy required, move small molecules/charged ions through tunnel-like proteins
ungated channels are
always opened
gated proteins
have open and closed conformations
how do gated proteins open/close
stimulated by changes in environment
carrier proteins vs channel proteins
carrier undergo conformational changes
what type of transport are carrier proteins involved in
passive and active
intracellular peripheral proteins are attached to
cell cytoskeleton, anchored/immobile on membrane
what is the cytoskeleton
a network of fibers extending throughout the cytoplasm
property of cytoskeleton
dynamic, easily dismantled and reassembled
3 components of cytoskeleton
microfilament, intermediate filament, microtubules
microfilaments made of
2 intertwined strands of actin
intermediate filaments made of
fibrous protein supercoiled
microtubules made of
hollow tube of 13 tubulin columns
microfilament functions (2)
maintain cell shape, muscle contraction
intermediate filament function
anchor organelles and cytosolic proteins
microtubule functions (2)
path for organelle/vesicle/chromosome movement, cell motility
organelles involved in cell motility
cilia, flagella
ecm made of
glycoproteins secreted by cells
function of extracellular matrix (3 points)
cell signalling, anchors cell - supports cell structure, separates tissue
where are carbs found (cell membrane)
extracellular side of the membrane
glycolipid
carb + lipid (or phospholipid)
function of carbs in cell membrane
identify the cell, act as a signaller for communication between cells
where is cholesterol found in the cell membrane
within fatty acid tails of bilayer
function of cholesterol in cell membrane
stabilize membrane
what affects fluidity of membrane
cholesterol, temperature, saturation of fatty acids, hydrophobic restrictions
how does saturation of fatty acids affect membrane fluidity
unsaturated = more fluid (kinks), saturated = viscous (packed too tightly)
5 types of mvmt w/i membrane
lateral diffusion, rotation, swing, flexion, transverse diffusion/flip flop
what is lateral diffusion
phospholipids transpose with neighbouring molecules (same leaflet)
what is swing (phospholipids)
tails move from side to side
what is flexion (phospholipids)
contractions
what is transverse diffusion
phospholipids move from 1 leaflet to the other
flipase
facilitates transverse diffusion
2 useful properties of cholesterol
large molecule size, non polar
how does cholesterol stabilize the membrane
large size interrupts intermolecular forces, non polarity stabilizes hydrophobic interactions + fills in kinks for unsaturated phospholipids
large size of cholesterol is more significvant
at low temperatures
non polarity of cholesterol is more significant
at high temperatures
importance of transverse motion being rare
helps maintain membrane asymmetry
2 types of cell junctions/cell adhesions
channel-forming, occluding
what are gap junctions
membrane proteins line up and form a channel, creates gaps that connects animal cells
occluding/tight junctions
form impermeable barriers between cells
homeostasis
constant internal environment is maintained despite changes in external environment
maintaining cellular environments is similar to
homeostasis in the body
2 forms of cellular transport
active, passive
3 types of passive transport
diffusion, osmosis, facilitated diffusion
simple diffusion
occurs directly through lipid bilayer
facilitated diffusion
occurs through a channel or carrier protein
molecules that go through facilitated diffusion
typically ions
proteins that facilitate osmosis
aquaporins
kmt full word
kinetic molecular theory
what is the kmt (3 points)
particles in constant random motion
particles collide, bounce off e/o, spread out
molecular collisions cause diffusion
another name for constant random motion
brownian motion
diffusion occurs until
equilibrium achieved
characteristics of molecules that go through simple diffusion
small, neutral molecules (e.g. O2 CO2)
concentration gradient relevance to diffusion
particles move from high concentration areas to low concentration areas
after equilibrium has been reached
molecules continue to move across the membrane, concentrations stay the same, no net mvmt
3 factors that affect diffusion
concentration, temperature, pressure
concentration effects on diffusion
increased concentration = increased speed of diffusion - more molecules = more collisions
how can diffusion rate increase
more collisions b/w molecules
temperature effects on diffusion
increased temperature = increased rate of diffusion
pressure effects on diffusion
increased pressure = increased rate of diffusion
3 types of solutions
hyper-, hypo-, isotonic
tonicity is
the osmotic pressure due to a diff. in concentration across a semi-permeable membrane
tonicity is affected by
solutes unable to cross the membrane
hypertonic solution definition
concentration of solute is higher outside than inside the cell
hypotonic solution definition
concentration of solute is lower outside than inside the cell
isotonic solution definition
concentration of solute is equal outside and inside the cell
shriveled cells were
placed in a hypertonic solution
lysed cells were
placed in a hypotonic solution
flaccid plant cells were
placed in an isotonic solution
tonicity related terms that only apply to plants
turgid, flaccid
water mvmt in hypertonic solution
water diffuses outwards
water mvmt in hypotonic solution
water diffuses inwards
water mvmt in isotonic solution
water diffuses in and out at an equal rate
what happens to cells in a hypertonic solution
shriveled, plasmolyzed
what happens to cells in a hypotonic solution
lysed
what happens to rbc in hypertonic solution
crenation
what happens to rbc in hypotonic solution
hemolysis
crenation occurs when
hypertonic solution, higher solute concentration outside of cell
hemolysis occurs when
hypotonic solution, higher solute concentration inside of cell
is facilitated diffusion active or passive
passive
example of molecules that use facilitated diffusion
K+ Na+ Cl-
moleculues that use facilitated diffusion
larger hydrophilic molecules
speed of facilitated diffusion depends on
proteins available, not concentration gradient
aquaporin charge
inside ins positively charged, outside is neutral
why do ions use channel proteins
have trouble crossing hydrophobic core
function of aquaporins
speed up diffusion of water
carrier proteins (active or passive)
passive
pumps (active or passive)
active
molecules that use carrier proteins
charged particles + large uncharged molecules (e.g. K+, glucose)
moving against the concentration gradient requires
active transport
active transport requires
energy from breakdown of atp
atp full word
adenosine triphosphate
atp rxn
atp -> adp + 1 inorganic phosphate + energy
coupling pumps means
transporting 2 molecules against the gradient at the same time
types of coupled transport
symport, antiport
example of a frequently used pump
sodium potassium pump
sodium potassium pump mechanics
3Na+ out of cell, 2K+ into cell - pump oscillates b/w conformational states
in a Na-K pump, which molecules move in/out of the cell
Na+ out of cell, K+ into cell
mvmt of ATP for a Na-K pump
atp split into adp + p (p stuck at pump) for Na+ to leave, K+ binding from outside triggers release of p which restores the original conformation
process of protein changing its conformation
phosphorylation
Na-K pump actual uses
nerve impulse conduction
2 types of bulk transport
endocytosis, exocytosis
bulk transport is used for
very large or very polar molecules - e.g. proteins, polysaccharides
3 types of endocytosis
phagocytosis, pinocytosis, receptor-mediated
process of endocytosis
cell engulfs extracellular fluid, folds into plasma membrane, pinched off inside, vesicle usu fuses w lysosome
pseudopod
extension of cell that wraps around particles
what is a phagosome
vacuole with food particles enclosed in it
what is a phagolysosome
phagosome fused with lysosome
why does the phagosome fuse with a lysosome
lysosome digests particles using hydrolytic enzymes
what happens after the lysosome has digested the food particles (in the phagolysosome)
indigestible material left in the vacuole (now called residual body) removed via exocytosis
what is a phagocyte
white blood cell specialized for protecting the body by ingesting foreign substances
purpose of phagocytosis
defense mechanism, form of feeeding
lysosome enzymes work best at what pH
pH of 5
how is lysosome pH maintained
pumping H+ into the lumen
why is lysosome pH different from cytosol pH
so that the enzymes do not break down the cell if they’re released
pinocytosis
phagocytosis but liquid
what is a ligand
a molecule that binds to a receptor
where are receptor proteins usually found
clustered in coated pits
which proteins help form vesicles for endocytosis
coat proteins - help with pinching
what is receptor mediated endocytosis
intake of molecules that bind specifically to a receptor
process of receptor mediated endocytosis
ligand bind to receptor, membrane pinches, ligand splits from receptor, ligand fuse with lysosome
what is a coated vesicle
vesicle containing ligands, receptors and coat proteins
organelle involved in exocytosis
golgi body (or the vesicle is from endocytosis in which case no organelle is involved)
function of exocytosis (3 points)
secretion, recycling membrane proteins, restoring cell membrane - keeping SA of membrane constant
