cell bio final Flashcards
only _______ actin is expressed in muscle cells
alpha
what are the three mechanisms of active transport?
- coupled transport
- ATP pumps
- light/redox reactions
where does the final shape of collagen happen
outside the cell
what kind of membranes do autophagosomes have?
double membranes
a two headed phospholipid exclusively present in the mitochondrial membranes. It is found in many bacterial membranes.
cardiolipin
kinesin walks towards which end of microtubules
plus end
two functions of integrins
adhesion (cell to ECM linkage) and signalling
what are the three phases of actin polymerization (ACTIN GROWTH/formation)
- nucleation/lag phase
- elongation/growth phase
- steady state/equilibrium phase
enzymes activated by extracellular signals to cleave specific phospholipids to release short- lived intracellular messages (aka second messengers)
phospholipases
how is mitochondrial DNA inherited
from mother to child
what do cilia and flagella contain (2)
dynein (motor protein) and microtubules
highly polar and negatively charged, has a strong tendency in attracting water molecules that give the matrix a gel-like composition
GAGs
what are cell junctions
cell - cell interations!
what are the three protein extraction methods?
- detergent based lysis
- osmotic shock
- changes in pH
connects actin filament bundle in one cell with that in the next one
adherens junction
what is the largest GAG
hyaluronic acid
movement of substances across the membrane using energy
active transport
cell eating
phagocytosis
nucleates microtubule branching
augmin
chemical bond forming reactions that generate ATP and membrane transport processes
chemiosmotic coupling
describes the structure of the plasma membrane as a mosaic of components including phospholipids, cholesterol, proteins, and carbohydrates
fluid mosaic model
what are the soluble subunits of intermediate filaments
dimers and tetramers
major sterol found in animal cells
Cholesterol
what links cells with the ECM
inegrins (proteins)
during apoptosis PS is externalized to the outer leaflet by
scramblases
where are microtubules nucleated
microtubule organizing center (MTOC)
how does collagen formation start
with a triple helix molecule (3 molecules of collagen form homo or heterotrimers)
what are cytoskeletal filaments made of
big picture: large helical insoluble filaments
zoom in: each filament is made of soluble monomers
The inner mitochondria membrane forms numerous folds which extend into the interior of the organelle, what are the folds called
cristae
are actin-based motor proteins that generates force by coupling ATP hydrolysis to conformational changes
Myosin proteins
what pump uses ATP hydrolysis to drive H + transport
V-type pump
the y tubulin ring complex in microtubules is similar to what in actin filaments
Arp2/3 complex (both nucleation complexes)
how can we visualize actin cytoskeleton in vivo?
incorporating fluorescently labeled actin
ex. staining F-actin in vivo with SiR- Actin, a cell-permeable noncytotoxic compound
yellow or orange pigments
carotenoids
anchors actin filaments in cell to extracellular matrix
focal adhesions/actin-linked cell matrix junction
Anchors intermediate filaments in cell to extracellular matrix
hemidesmosome
cell crawling relies on the
actin cytoskeleton
cell migration in response to soluble factors (concentration gradients of extracellular signals)
chemotaxis
why does the matrix have a slightly higher pH than the cytosol
cristae traps the proton because of its shape, this lets the protons stay close to the ATP synthase and makes synthesis of ATP more effective
encloses the matrix and contains all the protein complexes involved in the electron transport chain and the ATP synthase
inner mitochondrial membrane
cell drinking
pinocytosis
where photosynthesis and the synthesis of ATP takes place
Thylakoid membrane
WHO use the energy stored in concentration gradients to couple the uphill transport of one solute across the membrane to the downhill transport of another
couple transporters
channels only use what kind of transport
passive transport
Four ways of immobilizing specific membrane proteins through protein-protein interactions
- By forming large self-assembled protein aggregates
- By tethering(restricting) them to macromolecular assemblies outside the cell
- By tethering(restricting) them to macromolecular assemblies inside the cell
- By interacting with proteins on the surface of another cell
actin-based structures that act as platforms for the localized release of lytic enzymes that degrade the extracellular matrix (matrix degrading structures)
podosomes and invadopodia
which mitochondrial membrane contains B barrel proteins
outer mitochondrial
virus that uses dynein (and dynactin) and microtubules only
influenza
what are the three functions of accessory proteins in the cell cytoskeleton?
- assembly and disassembly of filaments
- link filaments to cells structures and between each other
- act as a bridge between the cytoskeleton and intra/extracellular signals
dynein walks towards which end of microtubules
minus end
movement of substances across the membrane without the expenditure of cellular energy
passive transport
why does the inner mitochondrial membrane have many pumps, channels and transporters
because it is almost impermeable, hard to cross
the most abundant glycolipids, affect the electrical environment of the cell membrane
gangliosides
intercellular adhesion complexes of claudin and occludin proteins that control paracellular permeability
tight junctions
In most transmembrane proteins, the polypeptide chain crosses the lipid bilayer in an ________ conformation
a-helical
a fungal toxin that binds and stabilizes F-actin and effectively prevents the depolymerization of actin fibers, toxic for the cell
phalloidin
in microtubules at which ends are alpha and beta tubulins exposed
alpha : minus end
beta: plus end
phospholipids have a _______ head and ______ tails, they are ___________
hydrophilic head (water loving head), polar
hydrophobic tails (water fearing tails), non-polar
they are amphiphilic
bind to and stabilizes microtubules causing a net increase in tubulin polymerization
taxol
name 4 parts of the basal lamina
proteoglycans, nidogen, collagen, laminin
a phospholipid that interacts with proteins involved in oxidative phosphorylation and the transport of ATP, in cristae its disposition supports membrane curvature
cardiolipin
what are the three major protein filaments in the cell cytoskeleton
actin filaments, microtubules, intermediary filaments
what couples uphill transport to the hydrolysis of ATP
ATP-driven pumps
connects intermediate filaments in one cell to those in the next
Desmosome
Approximately 50% of the dry mass of the plasma membrane
membrane proteins (protein channels, globular protein, peripheral protein, glycoprotein, integral protein, surface protein, a-helix protin)
Contains two central microtubules that are surrounded by an outer ring of nine doublet microtubules
axoneme (core of cilia and flagella)
small and transient (short lived) regions of the plasma membrane (microdomains) enriches in cholesterol and sphingolipids
lipid rafts
true or false
to study cell migration in the lab we use 2D models
false, we use 3D models
the thylakoid membrane corresponds to what in the mitochondria
cristae
The switch from polymerization to shrinkage is called a
Catastrophe
what cytoskeltal filament is abundant in an animal cell nucleus
intermediate filaments
what is the thickness of the plasma membrane
5 to 10 nm
what is the function of the plasma membrane
- encloses the cell
- defines the cells boundaries
- maintains differences between cytosol and extracellular environment
- mediates cell signalling
- controls passage of molecules in and out of the cell
the stroma is similar to what part of the mitochondira
matrix
what technique can we use to detect PS on death cells
flow cytometry
what is the core of cilia and flagella called?
axoneme
from what did mitochondria and chloroplasts originate
bacteria
the majorly of y tubulin ring complex is found where
cytoplasm (centrosome is in the cytoplasm)
which photosystem takes out electrons from water
photosystem II
binds to B tubulin and disrupts microtubule assembly/disassembly dynamics, depolarization agent
nocodazole
the structure of the lipid bilayer is
asymmetric
what is the major microtubule organizing centre in animal cells
centrosome
The electrons used in carbon fixation by chloroplasts ultimately come from:
WATER
what does cytochrome b6f complex do in ETC of photosynthesis
pumps protons into the thylakoid space
can act as a bridge to connect ECM and cells
glycoproteins…fibronectin
Does not provide cell anchorage but allows direct communication via specialized intercellular channels
gap junctions
most common protein found in ECM
collagen, fibrous protein
normally keep PS inside the cell
flippases
where do the protons go from water in photosynthesis
released into the thylakoid space by water oxidation
leaves become yellow: defects in chlorophyll produce is the most common viral symptoms
Chlorosis
harness energy to drive force and movement
motor proteins
has ADP/ATP carrier proteins that carriers ADP in and produced ATP out
inner mitochondrial membrane
The switch from shrinkage to polymerization
rescue
what macromolecules are founded in the ECM
- protoglycans and GAGs
- fibrous proteins
- glycoproteins
what are the subunits for the filaments in the cell cytoskeleton?
- actin filaments: actin subunits
- microtubules: tubulin subunits
- intermediary filaments: elongated and fibrous subunits
where is chlorophyll located
within the thylakoid membrane
what is the most abundant negatively charged phospholipid in eukaryotic membranes
PS = phosphatidylserine
true or false:
healthy and damaged mitochondria CANNOT co-exist
FALSE
healthy and damaged mitochondria can co-exist
the places where food-derived molecules are converted into energy (ATP)
matrix and cristae
uptake of large amounts of fluids and nutrients (it can also involve the uptake of big particles)
macropinocytosis
accessory protein that nucleates assembly and remains associated with the growing plus end of actin
formin
what is dynamin involved in
- endocytosis
- phagocytosis
- mitochondria fission
what is the structure of microtubules
two globular proteins (alpha and beta) in the form of a heterodimer
binds ADP actin filaments, accelerates disassembly
cofilin
whats bigger mitochondria or chloroplasts?
chloroplasts
Conversion of light energy into chemical energy: occurs entirely within the
thylakoid membrane
why do many many proteins need to be imported into the mitochondria
the mitochondria contains less than of the proteins that the mitochondria needs to funciton
a rare inherited blood disease due to a group of metabolic disorders of the heme biosynthetic pathway (altered enzymatic activity)
Porphyria
Cell migration depends on the
actin cortex
thin membranous cytoplasmic protrusions to sample the extracellular environment
Filopodia
how are anthocyanins formed
reaction between sugar and proteins in cell sap!
- sugar concentration must be high and it is since temperatures are cooled and this causes leaf veins to close, and sugars are stuck
accessory protein that nucleates assembly to form a branches network and remains associated with the minus end of actin filaments
Arp/2/3 complex
The removal of bad or damaged mitochondria by autophagy
mitophagy
what at the cell cortex determines cell shape
actin
stabilize microtubules by binding along sides
MAPs
Play critical roles in cell recognition and help maintain the stability of the plasma membrane
glycolipids
a hollow cylindrical structure built from 13 parallel protofilaments, each composed of alpha-beta tubulin heterodimers
microtubule
at low concentrations it stops the growth of microtubules, while at high concentrations it promotes their depolarization
colchicine
what three stimuli can open ion channels?
- Voltage gated: change in voltage
- Ligand gated:binding to extracellular or intracellular ligands
- mechanically gates: mechanical stress
virus that uses dynein, kinesin, and microtubules
herpes
what kind of charged molecules are favoured into the cell
positively charged molecules
WHY? because inner leaflet is negatively charged
nucleates assembly and remains associated with the minus end of microtubules
y-TuRC
is the carbohydrate-rich zone on the cell surface that protects the membrane from the harsh and dynamic microenvironment that could damage the lipids and proteins
glycocalyx
building polymers from smaller parts called monomer
polymerization
flat and wide cytoplasmic protrusions at the periphery of a migrating cell
- Protrusions are enriched with a branches network of actin filaments
lamellipodia
involved in muscle contraction
myosin II
what are the two main classes of membrane transport proteins
transporters and channels
the principal sites
of intracellular digestion
lysosomes
