exam 4 Flashcards
1
Q
Which of the following is a short-range signaling mechanism that enables cells to signal to other cells via secreted local mediators?
A
endocrine
2
Q
Which of the following binding domains enables proteins to bind to phosphoinositides?
A
PH
3
Q
The secondary messenger, cAMP activates which enzyme?
A
PKA
4
Q
Protein that binds to a GTP- binding protein and activates it by stimulating release of tightly bound GDP, thereby allowing it to bind GTP
A
Guanine nucleotide exchange factor (GEF)
5
Q
General term for a protein that binds a specific extracdllular molecule (ligand) and initiates a response in the cell
A
receptor
6
Q
Alteration of sensitivity following repeated stimulation, reducing a cells response to that level of stimulus
A
adaptation or desensitization
7
Q
Compact protein module that binds to a particular structural motif in another protein (or lipid) molecule with which the signaling protein interacts
A
interaction domain
8
Q
Short-range cell-cell communication via secreted local mediators that act on adjacent cells
A
paracrine signaling
9
Q
A signal relay chain involving multiple protein kinases, each of which is activated by phosphorylation and then phosphorylates the next protein kinase in the sequence
A
kinase cascade
10
Q
Small molecule that is formed in the cytosol, or released into it, in response to an extracellular signal and that helps to relay the signal to the interior of the cell
A
second messenger
11
Q
Specialized animal cell that secretes a hormone into the blood
A
endocrine cell
12
Q
Molecule from outside the cell that communicates the behavior or actions of other cells in the environment and elicits an appropriate response
A
extracellular signal molecule
13
Q
Enzyme that transfers the terminal phosphate group of ATP to a specific amino acid of a target protein
A
protein kinase
14
Q
Small signal molecule secreted by the presynaptic nerve cell at a chemical synapse to relay the signal to the postsynaptic cell
A
neurotransmitter
15
Q
Protein that binds to a GTP-binding protein and inactivates it by stimulating its GTPase activity so that its bound GTP is hydrolyzed to GDP
A
GTP-ase activating protein
16
Q
Protein that organizes groups of interacting intracellular signaling proteins into signaling complexes
A
scaffold protein
17
Q
Cell-cell communication in which the signal molecule remains bound to the signaling cell and only influences cells that physically touch it
A
contact-dependent signaling
18
Q
G protein that activates adenylyl cyclase and thereby increases cyclic AMP concentration
A
stimulatory G protein
19
Q
Protein composed of three subunits, one of which is activated by the binding of GTP
A
trimeric GTP-binding protein
20
Q
Ubiquitous calcium-binding protein whose interactions with other proteins are governed by changes in intracellular Ca2+ concentration
A
Calmodulin
21
Q
Enzyme that hydrolyzes cyclic AMP to adenosine 5’-monophosphate (5’-AMP)
A
cyclic AMP phosphodiesterase
22
Q
Cell-surface receptor that associates with an intracellular G protein upon activation by an extracellular ligand
A
G-protein-coupled receptor
23
Q
Enzyme that participates in desensitization of GPCRs by phosphorylating them after they have been activated by ligand binding
A
GPCR kinase
24
Q
Ca2+ release channel in the ER membrane that is activated by Ca2+ binding in the absence of IP3
A
ryanodine receptor
25
Enzyme bound to the cytoplasmic surface of the plasma membrane that converts membrane PI(4,5)P2 to diacylglycerol and IP3
phospholipase C-B (PLCB)
26
Protein that is an a-subunit-specific GTPase-activating protein (GAP)
regulator of G protein signaling (RGS)
27
Second messenger that is released from a phospholipid in the plasma membrane and diffuses to the ER, where it opens Ca2+ release channels
inositol 1,4,5-triphosphate (IP3)
28
Enzyme that phosphorylates target proteins in response to a rise in intracellular cyclic AMP
cyclic AMP-dependent protein kinase (PKA)
29
A Ca2+ dependent protein kinase that is activated by diacylglycerol
protein kinase C (PKC)
30
Light sensitive GPCR in rod photoreceptor cells of the retina
rhodopsin
31
Protein kinase whose activity is regulated by the binding of Ca2+ activated calmodulin, and which indirectly mediates the effects of Ca2+ by phosphorylation of other proteins
Ca2+/calmodulin-dependent kinase (CaM-kinase)
32
Protein that binds to the cyclic AMP response elements found in the regulatory region of many genes activated by cyclic AMP
CRE-binding (CREB) protein
33
The largest class of cell-surface-bound extracellular signal proteins
Ephrins
34
Large family of structurally related, secreted, dimeric proteins that act as hormones and local mediators to control a wide range of biological function in all animals
transforming growth factor-B superfamily (TGFB)
35
Cell-surface receptor that when activated by ligand binding adds phosphates from ATP to tyrosine side chains in its own cytoplasmic domain
receptor tyrosine kinase (RTK)
36
The founding member of a superfamily of monomeric GTPases that help to relay signals from cell-surface receptors to the nucleus
Ras
37
A group of monomeric GTPases that regulate both the actin and microtubule cytoskeletons
Rho family
38
Cytoplasmic tyrosine kinase present at cell-matrix junctions in association with the cytoplasmic tails of integrins
focal adhesion kinase (FAK)
39
A kinase that is involved in intracellular signaling pathways activated by cell-surface receptors and that phosphorylates inositol phospholipids at the 3 position of the inositol ring
phosphoinositide 3-kinase (PI 3-kinase)
40
Cell-surface receptor that activates a tyrosine kinase that is noncovalently bound to the receptor
tyrosine-kinase-associated receptor
41
A three-component signaling module used in various signaling pathways in eukaryotic cells
MAP kinase module
42
One of several intracellular signaling pathways that leads from cell-surface receptors to the nucleus, it is distinguished by providing one of the more direct routes
JAK-STAT signaling pathway
43
Protein domain found in intracellular signaling proteins by which they bind to inositol phospholipids phosphorylated by PI 3-kinase
Pleckstrin homology (PH) domain
44
A protein domain that is homologous to a region in Src, is present in many proteins, and binds to a short amino acid sequence containing a phosphotyrosine
SH2 domain
45
A crucial signaling protein in the PI-3-kinase-Akt signaling pathway, so named because it is the target of rapamycin
TOR or mTOR
46
Receptor protein involved in what may be the most widely used signaling pathway in animal development; its ligands are cell-surface proteins such as Delta
Notch
47
A family of secreted signal molecules that act as local mediators and morphogens during development; they were initially discovered as the products of the Wingless gene in flies and the Int1 gene in mice
Wnt proteins
48
A signaling pathway activated by Wnt binding to both the Frizzled receptor and the LRP co-receptor
Wnt/B-catenin pathway
49
A group of secreted signal molecules that act as local mediators and morphogens during development and whose effects are mediated through the cell-surface receptor Patched and its binding partner Smoothened
Hedgehog proteins
50
A target of Hedgehog signaling, this gene regulatory molecule is a full length gene activator in the presence of Hedgehog and a partially proteolyzed gene repressor in its absence
Cubitus interruptus (Ci)
51
Latent gene regulatory proteins that are present in most cells in both animals and plants and are central to many stress, inflammatory, and innate immune responses
NFKB proteins
52
Hydrophobic signaling molecule with a characteristic four-ringed structure derived from cholesterol
steroid hormone
53
A linear chain of protein subunits joined end to end, which associates laterally with other such chains to form cytoskeletal components
protofilament
54
System of protein filaments in the cytoplasm of a eukaryotic cell that gives the cell its shape and the capacity for directed movement
cytoskeleton
55
The process by which a polymeric protein filament is maintained at constant length by addition of protein subunits at one end and loss of subunits at the other
treadmilling
56
Specialized layer of cytoplasm on the inner face of the plasma membrane, rich in actin filaments
cell cortex
57
Protein assembly that nucleates actin filament growth from the minus end, allowing rapid growth at the plus end and forming a treelike web of filaments
Arp2/3 complex
58
The motor protein in muscle that generates the force for muscle contraction
myosin
59
Long, highly organized bundle of actin, myosin, and other proteins in the cytoplasm of muscle cells that contracts by a sliding-filament mechanism
myofibril
60
The property of sudden conversion feom growth to shrinkage, and vice versa, in a protein filament such as a microtubule or an actin filament
dynamic instability
61
Centrally located organelle of animal cells that is the primary microtubule-organizing center and acts as the spindle pole during mitosis
centrosome
62
Protein assembly containing a special form of tubulin, along with other proteins, that is an efficient nucleator of microtubule growth
y-Tubulin ring complex (y-TuRC)
63
Short cylindrical array of microtubules, a pair of which are embedded in the major microtubule-organizing center of an animal cell
centriole
64
A member of the family of motor proteins that move along microtubules by walking toward the minus end
dynein
65
A motor protein that moves along microtubules by walking toward the plus end
kinesin
66
Bundle of mixrotubules and associated proteins that forms the core of a cilium or flagellum in a eukaryotic cell and is responsible for their movements
axoneme
67
Long, hairlike protrusion from the surface of a eukaryotic cell whose endulations drive the cell through a liquid medium
flagellum
68
A group of closely related monomeric GTPases that includes Cdc42, Rac, and Rho
Rho family protein
69
Flattened, two-dimensional protrusion of membrane, supported by a meshwork of actin filaments, that is extended from the leading edge of crawling epithelial cells, fibroblasts, and some neurons
lamellipodium
70
Essentially a one-dimensional structure that protrudes from a cell and contains a core of long, bundled actin filaments
filopodium
71
A distinct form of membrane protrusion that is often observed when cells are cultured on a pliable extracellular matrix substrate
blebbing
72
The long period of the cell cycle between one mitosis and the next
interphase
73
The orderly sequence of events by which a cell duplicates its contents and divides into two
cell cycle
74
The checkpoint in the cell cycle that governs the cell's commitment to enter S phase
Start or restriction point
75
The phase of the eukaryotic cell cycle between the end of cytokinesis and the start of DNA synthesis
G1 phase
76
A member of the family of protein kinases that have to be complexed with a cyclin protein in order to act
Cyclin-dependent kinase(Cdk)
77
The ubiquitin ligase that promotes the destruction of a specific set of proteins, thereby promoting the separation of sister chromatids and the completion of M phase
anaphase promoting complex or cyclosome (APC/C)
78
The cyclin-Cdk complex responsible for stimulating entry into mitosis at the G2/M checkpoint
M-Cdk
79
One of a family of proteins that rise and fall in concentration in step with the eukaryotic cell cycle, thereby regulating the activity of the crucial protein kinases that control progression through the cell cycle
cyclin
80
The final major checkpoint in the cell cycle, where the control system stimulates sister-chromatid separation, leading to the completion of mitosis and cytokinesis
metaphase-to-anaphase transition
81
A timing mechanism that triggers events of the cell cycle in a set sequence, using feedback from the processes it controls ro ensure that one stage is complete before the next one begins
cell-cycle control system
82
General term for one of the several protein assemblies that form periodically during the cell cycle as the level of cyclin increases, and partially activate the cyclin-dependent kinase component
cyclin-Cdk complex
83
Complex of proteins that holds sister chromatids together along their length until they separate at mitosis
cohesin
84
Large protein complex that is bound throughout the cell cycle at origins of replication in eukaryotic chromosomes
origin replication complex (ORC)
85
Protein that binds to and inhibits ankey component of the prereplicative complex
geminin
86
Movement of tubulin subunits toward the spindle poles as a result of addition of new subunits at the plus ends of microtubules and their disassembly at minus ends
microtubule flux
87
Stage of mitosis in which the spindle poles move apart
anaphase B
88
Mechanism ensuring that cells do not enter anaphase until all chromosomes are correctly bi-oriented on the mitotic spindle
spindle assembly checkpoint
89
Centrally located organelle of animal cells that after duplication organizes each spindle pole suring mitosis
centrosome
90
Imaginary plane midway between the spindle poles in which chromosomes are positioned at metaphase
metaphase plate
91
Microtubules that overlap in the spindle midzone and interact via their plus ends, generating an antiparallel array
interpolar microtubules
92
Final stage of mitosis in which the two sets of separated chromosomes decondense and become enclosed by nuclear envelopes
telophase
93
Complex of proteins that uses the energy of ATP hydrolysis to promote the compaction and resolution of sister chromatids
condensin
94
Protease whose activation at the end of metaphase results in the cleavage of cohesin and the separation of sister chromatids
separase
95
Microtubule that radiates outward from the spindle pole and contacts the cell cortex, helping to position the spindle in the cell
astral microtubule
96
Cytoplasm containing many nuclei enclosed by a single plasma membrane
syncytium
97
Structure formed at the end of cleavage that can persist for some time as a tether between the two daughter cells
midbody
98
Division of the cytoplasm of a plant or animal cell into two
cytokinesis
99
Structure made of microtubules and actin filaments that forms in the prospective plane of division of a plant cell and guides formation of the cell plate
phragmoblast
100
Circular band containing actin and myosin that forms under the surface of animal cells undergoing cell division and contracts to pinch the two daughter cells apart
contractile ring
101
Protease that has a cysteine at its active site and cleaves its target proteins at specific aspartic acids
caspase
102
Wheel-like assembly composed of seven copies of the Apaf1/cytochrome c complex
apoptosome
103
Form of cell death that leads fo fragmentation of the DNA, shrinkage of the cytoplasm, membrane changes, and cell death, without lysis or damage to neighboring cells
apoptosis
104
An assembly of several proteins, including initiator caspases, on the cytosolic portion of the Fas death receptor
Death-inducing signaling complex (DISC)
105
Apoptotic program triggered by the binding of an extracellular signal protein
extrinsic pathway
106
Extracellular signal molecule that inhibits apoptosis
survival factor
107
Apoptotic program that depends on the release into the cytosol of proteins from the mitochondrial intermembrane space
intrinsic pathway
108
Cell-surface molecule that triggers apoptosis when bound by an extracellular signal protein
death receptor
109
When cleaved by an initiator caspase, this protease is activated and participates in the widespread cleavage events that kill the cell
executioner caspase
110
Ras is activated by Sos. What type of protein is Sos?
GEF
111
MEK is downstream of Ras and activates the MAP kinase, ERK. What type of enzyme is MEK?
MAP kinase kinase
112
What type of transcription factors do the JAKs regulate?
STAT
113
In a growing actin filament, which end typically grows fastest?
plus end
114
Which of these actin-binding proteins is required for the formation of Z-disks in skeletal muscle cells?
Alpha-actinin
115
Listeria travels around within cells by constructing actin filaments using host proteins and bacterial proteins. Which of the following proteins is a bacterial protein found on the outer surface of Listeria?
Acta
116
When are microtubules most stable?
when the beta subunit is binding GTP
117
Microtubules radiate out from the MTOC. Which ends are furthest away from the centrioles?
plus ends
118
What transmembrane proteins are present in focal adhesions that help cells gain traction with the extracellular matrix?
myosin
119
Which of the following proteins is involved in the disassembly of actin filaments behind the leading edge of a migrating cell?
cofilin
120
Which cyclins would you expect to be highly expressed during G1?
Cyclin D
121
Which of the following regulatory proteins inhibits the activity of certain cyclin:Cdk complexes?
Wee1
122
If cells are exposed to DNA-damaging agents they might upregulate...
p21
123
What is the role of separase enzymes during the cell cycle?
cleave cohesins
124
Which conditions can activate p53?
DNA double strand breaks caused by exposure to x- or gamma rays
DNA damage caused by UV exposure
excessive stimulation of mitogenic pathways
125
Which transcription factor is inhibited by active Rb proteins?
E2F
126
Which of the following is an anti-apoptotic member of the Bcl-2 family?
BclXl
127
In the extrinsic pathway of apoptosis, what role does caspase-8 play?
it is an initiator caspase
128
Name the different types of intercellular signaling
contact dependent
paracrine
endocrine
synaptic
129
Name the types of cell surface receptors
ion-channel-coupled receptors
G-protein-coupled receptors
Enzyme-coupled receptors
130
How are RTKs activated?
by signaling proteins that cause dimerization and trans-autophosphorylation
131
What are the 3 main types of cytoskeletal protein filament?
actin, microtubules, intermediate filaments
132
What is the location within the cell of actin?
actin is highly concentrated in the cortex just beneath the plasma membrane
133
What is the location within the cell of intermediate filaments?
they can be beneath the inner nuclear membrane as nuclear lamina or extend across the cytoplasm
134
What are microtubules attached to?
a microtubule organizing center (MTOC) called a centrosome
135
What is nucleation?
it is the rate limiting step in the formation of cytoskeletal polymers
136
What does troponin do?
controls skeletal muscle contraction by a troponin complex of T, I, and C polypeptides; tropomyosin binding, inhibitory activity, and Ca2+ binding (TIC)
137
Role of tropomyosin?
Prevents myosin cross bridging with actin in the absence of Ca2+
138
Smooth muscle contraction requires?
Ca2+ dependent calmodulin to activate MLCK or myosin light chain kinase
139
What is kinesin and what does it do? What is dynein?
it is a plus end motor protein that generates force by coupling ATP hydrolysis to conformational changes
dynein is a minus end motor protein that does same thing
140
What are the microtubule motor proteins and what do they do?
kinesins and dyneins;
| they move organelles across microtubules
141
Cell migration occurs how?
by a actin cytoskeleton that generates force
142
What is dynamic instability?
the rapid interconversion between a growing and shrinking state of microtubules
143
What is catastrophe?
the random loss of GTP cap that leads to rapid shrinkage in microtubule dynamic instability
144
What is rescue?
the regain of GTP cap that leads to rapid growth in microtubule dynamic instability
145
What is the function of cohesions?
hold sister chromatids together at the end of S phase
| is a large protein complex that forms a ring around the sister chromatids
