cell bio final Flashcards
(129 cards)
1
Q
only _______ actin is expressed in muscle cells
A
alpha
2
Q
what are the three mechanisms of active transport?
A
- coupled transport
- ATP pumps
- light/redox reactions
3
Q
where does the final shape of collagen happen
A
outside the cell
4
Q
what kind of membranes do autophagosomes have?
A
double membranes
5
Q
a two headed phospholipid exclusively present in the mitochondrial membranes. It is found in many bacterial membranes.
A
cardiolipin
6
Q
kinesin walks towards which end of microtubules
A
plus end
7
Q
two functions of integrins
A
adhesion (cell to ECM linkage) and signalling
8
Q
what are the three phases of actin polymerization (ACTIN GROWTH/formation)
A
- nucleation/lag phase
- elongation/growth phase
- steady state/equilibrium phase
9
Q
enzymes activated by extracellular signals to cleave specific phospholipids to release short- lived intracellular messages (aka second messengers)
A
phospholipases
10
Q
how is mitochondrial DNA inherited
A
from mother to child
11
Q
what do cilia and flagella contain (2)
A
dynein (motor protein) and microtubules
12
Q
highly polar and negatively charged, has a strong tendency in attracting water molecules that give the matrix a gel-like composition
A
GAGs
13
Q
what are cell junctions
A
cell - cell interations!
14
Q
what are the three protein extraction methods?
A
- detergent based lysis
- osmotic shock
- changes in pH
15
Q
connects actin filament bundle in one cell with that in the next one
A
adherens junction
16
Q
what is the largest GAG
A
hyaluronic acid
17
Q
movement of substances across the membrane using energy
A
active transport
18
Q
cell eating
A
phagocytosis
19
Q
nucleates microtubule branching
A
augmin
20
Q
chemical bond forming reactions that generate ATP and membrane transport processes
A
chemiosmotic coupling
21
Q
describes the structure of the plasma membrane as a mosaic of components including phospholipids, cholesterol, proteins, and carbohydrates
A
fluid mosaic model
22
Q
what are the soluble subunits of intermediate filaments
A
dimers and tetramers
23
Q
major sterol found in animal cells
A
Cholesterol
24
Q
what links cells with the ECM
A
inegrins (proteins)
25
during apoptosis PS is externalized to the outer leaflet by
scramblases
26
where are microtubules nucleated
microtubule organizing center (MTOC)
27
how does collagen formation start
with a triple helix molecule (3 molecules of collagen form homo or heterotrimers)
28
what are cytoskeletal filaments made of
big picture: large helical insoluble filaments
zoom in: each filament is made of soluble monomers
29
The inner mitochondria membrane forms numerous folds which extend into the interior of the organelle, what are the folds called
cristae
30
are actin-based motor proteins that generates force by coupling ATP hydrolysis to conformational changes
Myosin proteins
31
what pump uses ATP hydrolysis to drive H + transport
V-type pump
32
the y tubulin ring complex in microtubules is similar to what in actin filaments
Arp2/3 complex (both nucleation complexes)
33
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
34
yellow or orange pigments
carotenoids
35
anchors actin filaments in cell to extracellular matrix
focal adhesions/actin-linked cell matrix junction
36
Anchors intermediate filaments in cell to extracellular matrix
hemidesmosome
37
cell crawling relies on the
actin cytoskeleton
38
cell migration in response to soluble factors (concentration gradients of extracellular signals)
chemotaxis
39
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
40
encloses the matrix and contains all the protein complexes involved in the electron transport chain and the ATP synthase
inner mitochondrial membrane
41
cell drinking
pinocytosis
42
where photosynthesis and the synthesis of ATP takes place
Thylakoid membrane
43
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
44
channels only use what kind of transport
passive transport
45
Four ways of immobilizing specific membrane proteins through protein-protein interactions
1. By forming large self-assembled protein aggregates
2. By tethering(restricting) them to macromolecular assemblies outside the cell
3. By tethering(restricting) them to macromolecular assemblies inside the cell
4. By interacting with proteins on the surface of another cell
46
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
47
which mitochondrial membrane contains B barrel proteins
outer mitochondrial
48
virus that uses dynein (and dynactin) and microtubules only
influenza
49
what are the three functions of accessory proteins in the cell cytoskeleton?
1. assembly and disassembly of filaments
2. link filaments to cells structures and between each other
3. act as a bridge between the cytoskeleton and intra/extracellular signals
50
dynein walks towards which end of microtubules
minus end
51
movement of substances across the membrane without the expenditure of cellular energy
passive transport
52
why does the inner mitochondrial membrane have many pumps, channels and transporters
because it is almost impermeable, hard to cross
53
the most abundant glycolipids, affect the electrical environment of the cell membrane
gangliosides
54
intercellular adhesion complexes of claudin and occludin proteins that control paracellular permeability
tight junctions
55
In most transmembrane proteins, the polypeptide chain crosses the lipid bilayer in an ________ conformation
a-helical
56
a fungal toxin that binds and stabilizes F-actin and effectively prevents the depolymerization of actin fibers, toxic for the cell
phalloidin
57
in microtubules at which ends are alpha and beta tubulins exposed
alpha : minus end
beta: plus end
58
phospholipids have a _______ head and ______ tails, they are ___________
hydrophilic head (water loving head), polar
hydrophobic tails (water fearing tails), non-polar
they are amphiphilic
59
bind to and stabilizes microtubules causing a net increase in tubulin polymerization
taxol
60
name 4 parts of the basal lamina
proteoglycans, nidogen, collagen, laminin
61
a phospholipid that interacts with proteins involved in oxidative phosphorylation and the transport of ATP, in cristae its disposition supports membrane curvature
cardiolipin
62
what are the three major protein filaments in the cell cytoskeleton
actin filaments, microtubules, intermediary filaments
63
what couples uphill transport to the hydrolysis of ATP
ATP-driven pumps
64
connects intermediate filaments in one cell to those in the next
Desmosome
65
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)
66
Contains two central microtubules that are surrounded by an outer ring of nine doublet microtubules
axoneme (core of cilia and flagella)
67
small and transient (short lived) regions of the plasma membrane (microdomains) enriches in cholesterol and sphingolipids
lipid rafts
68
true or false
to study cell migration in the lab we use 2D models
false, we use 3D models
69
the thylakoid membrane corresponds to what in the mitochondria
cristae
70
The switch from polymerization to shrinkage is called a
Catastrophe
71
what cytoskeltal filament is abundant in an animal cell nucleus
intermediate filaments
72
what is the thickness of the plasma membrane
5 to 10 nm
73
what is the function of the plasma membrane
1. encloses the cell
2. defines the cells boundaries
3. maintains differences between cytosol and extracellular environment
4. mediates cell signalling
5. controls passage of molecules in and out of the cell
74
the stroma is similar to what part of the mitochondira
matrix
75
what technique can we use to detect PS on death cells
flow cytometry
76
what is the core of cilia and flagella called?
axoneme
77
from what did mitochondria and chloroplasts originate
bacteria
78
the majorly of y tubulin ring complex is found where
cytoplasm (centrosome is in the cytoplasm)
79
which photosystem takes out electrons from water
photosystem II
80
binds to B tubulin and disrupts microtubule assembly/disassembly dynamics, depolarization agent
nocodazole
81
the structure of the lipid bilayer is
asymmetric
82
what is the major microtubule organizing centre in animal cells
centrosome
83
The electrons used in carbon fixation by chloroplasts ultimately come from:
WATER
84
what does cytochrome b6f complex do in ETC of photosynthesis
pumps protons into the thylakoid space
85
can act as a bridge to connect ECM and cells
glycoproteins...fibronectin
86
Does not provide cell anchorage but allows direct communication via specialized intercellular channels
gap junctions
87
most common protein found in ECM
collagen, fibrous protein
88
normally keep PS inside the cell
flippases
89
where do the protons go from water in photosynthesis
released into the thylakoid space by water oxidation
90
leaves become yellow: defects in chlorophyll produce is the most common viral symptoms
Chlorosis
91
harness energy to drive force and movement
motor proteins
92
has ADP/ATP carrier proteins that carriers ADP in and produced ATP out
inner mitochondrial membrane
93
The switch from shrinkage to polymerization
rescue
94
what macromolecules are founded in the ECM
1. protoglycans and GAGs
2. fibrous proteins
3. glycoproteins
95
what are the subunits for the filaments in the cell cytoskeleton?
1. actin filaments: actin subunits
2. microtubules: tubulin subunits
3. intermediary filaments: elongated and fibrous subunits
96
where is chlorophyll located
within the thylakoid membrane
97
what is the most abundant negatively charged phospholipid in eukaryotic membranes
PS = phosphatidylserine
98
true or false:
healthy and damaged mitochondria CANNOT co-exist
FALSE
healthy and damaged mitochondria can co-exist
99
the places where food-derived molecules are converted into energy (ATP)
matrix and cristae
100
uptake of large amounts of fluids and nutrients (it can also involve the uptake of big particles)
macropinocytosis
101
accessory protein that nucleates assembly and remains associated with the growing plus end of actin
formin
102
what is dynamin involved in
1. endocytosis
2. phagocytosis
3. mitochondria fission
103
what is the structure of microtubules
two globular proteins (alpha and beta) in the form of a heterodimer
104
binds ADP actin filaments, accelerates disassembly
cofilin
105
whats bigger mitochondria or chloroplasts?
chloroplasts
106
Conversion of light energy into chemical energy: occurs entirely within the
thylakoid membrane
107
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
108
a rare inherited blood disease due to a group of metabolic disorders of the heme biosynthetic pathway (altered enzymatic activity)
Porphyria
109
Cell migration depends on the
actin cortex
110
thin membranous cytoplasmic protrusions to sample the extracellular environment
Filopodia
111
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
112
accessory protein that nucleates assembly to form a branches network and remains associated with the minus end of actin filaments
Arp/2/3 complex
113
The removal of bad or damaged mitochondria by autophagy
mitophagy
114
what at the cell cortex determines cell shape
actin
115
stabilize microtubules by binding along sides
MAPs
116
Play critical roles in cell recognition and help maintain the stability of the plasma membrane
glycolipids
117
a hollow cylindrical structure built from 13 parallel protofilaments, each composed of alpha-beta tubulin heterodimers
microtubule
118
at low concentrations it stops the growth of microtubules, while at high concentrations it promotes their depolarization
colchicine
119
what three stimuli can open ion channels?
1. Voltage gated: change in voltage
2. Ligand gated:binding to extracellular or intracellular ligands
3. mechanically gates: mechanical stress
120
virus that uses dynein, kinesin, and microtubules
herpes
121
what kind of charged molecules are favoured into the cell
positively charged molecules
WHY? because inner leaflet is negatively charged
122
nucleates assembly and remains associated with the minus end of microtubules
y-TuRC
123
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
124
building polymers from smaller parts called monomer
polymerization
125
flat and wide cytoplasmic protrusions at the periphery of a migrating cell
- Protrusions are enriched with a branches network of actin filaments
lamellipodia
126
involved in muscle contraction
myosin II
127
what are the two main classes of membrane transport proteins
transporters and channels
128
the principal sites
of intracellular digestion
lysosomes
129
