Week 1 (Exam 1): Cell Communication & Development; Cell Form & Function (Diversity, Multicellular Tissues) Flashcards
1
Q
endocrine signaling
A
signaling through the circulatory system
2
Q
paracrine signaling
A
signaling by diffusion with small, water-soluble molecules such as growth factors
3
Q
growth factor
A
causes responding cell to grow, divide, or differentiate
- influences the types of cells their neighbors will become
4
Q
what are growth factors secreted by
A
embryonic cells
5
Q
synaptic signaling
A
specialized form of short-range signaling
-communication between neurons and between neurons and muscle cells
6
Q
response to synaptic signaling
A
-if the adjacent cell is a neuron, it will respond by carrying on the nerve impulse
-if the adjacent cell is a muscle cell, it may respond by contracting
7
Q
autocrine signaling
A
self-signaling by diffusion
8
Q
contact-dependent signaling
A
a transmembrane protein on the surface of one cell acts as the signaling molecule, and a transmembrane protein on the adjacent cell acts as the receptor
9
Q
what is contact-dependent signaling important for?
A
the development of the nervous system of vertebrates
10
Q
what is Delta?
A
a transmembrane protein
11
Q
what happens if a cell has more Delta?
A
it will become a neuron
12
Q
what does Delta bind to?
A
Notch receptors
13
Q
what happens if a cell has more Notch receptors?
A
it becomes a glial cell
14
Q
are there more glial cells or neurons in the central nervous system?
A
glial cells
15
Q
ligand
A
signaling molecule
16
Q
ligand-bonding site
A
the specific part of the receptor protein that the signaling molecule binds to
17
Q
where are receptors for polar signaling located?
A
cell membrane
18
Q
what does the location of receptors depend on?
A
whether the signaling molecule is polar or nonpolar
19
Q
what domains do transmembrane proteins have
A
an extracellular domain, a transmembrane domain, and a cytoplasmic domain
20
Q
extracellular domain
A
the part of a transmembrane protein that lies outside of the cells
21
Q
transmembrane domain
A
the part of a transmembrane protein that lies on the cell membrane
22
Q
cytoplasmic domain
A
the part of a transmembrane protein that lies inside the cell
23
Q
where are the receptors for nonpolar signaling molecules located
A
inside the cell
24
Q
totipotent cell potential
A
can form all the cell types in an organism
-ex zygote
25
pluripotent cell potential
can generate all the different types of cells in the body
-ex embryonic stem cells
26
multipotent cell potential
can produce some or all of the mature cell types found within a particular tissue
-ex neural progenitor cells
27
why is cell communication so important?
it is integral for coordinating cellular division, function, and cell differentiation (specialization)
28
four requirements to build a multicellular organism
-cell growth & division
-cell communication
-cell specialization
-cell-cell adhesion
29
which molecules can cross the cell membrane by simple diffusion?
lipids
30
what happens to a signal after it binds the receptor?
it eventually dissociates from the receptor
-doesn’t necessarily need the termination signal, because it takes a lot more energy to wait for the termination signal
31
is a protein always active when it is phosphorylated?
no
32
four major steps of the signal transduction process
-receptor activation
-signal transduction
-response
-termination
33
receptor activation step
the signal binds to a receptor
34
signal transduction step
the signal is transmitted to the interior of the cell by a signal transduction pathway
35
response step
the cell performs a task
36
termination step
the signal pathway is cut off so no new signals can be received
37
what is the role of phosphorylation?
phosphorylation is conducted by the kinases enzyme, and it phosphorylates proteins
38
what is the role of dephosphorylation
removing a phosphate group from a protein with phosphotases
39
kinase function
phosphorylation
40
phosphotase function
dephosphorylation
41
short-term cellular response
trigger movement within the cell, such as changes in cell shape or movement of vesicles to the membrane
42
long-term cellular response
trigger permanent changes to the cell, such as activation of transcription
43
four types of tissues
epithelial, connective, muscle, and nervous
44
tissues
collections of cells that carry out a specific function
45
organs
a combination of tissues, such as the heart, lung, or kidney
46
epithelial tissue function
provides a lining for all the spaces inside and outside hte body
47
where is epithelial tissue found?
-outer lining of the skin
-inner lining of the gut, bladder, & blood vessels
48
characteristics of epithelial tissue
-closely packed together and connected by cellular junction
-continuous sheet of cells
-layered
-may absorb and secrete substances as well as forming a boundary
49
simple epithelial tissue
one layer of cells
50
stratified epithelial tissue
more than one layer of cells
51
squamous epithelial tissue
made of flat cells
52
cuboidal epithelial tissue
made of round/square cells
53
columnar epithelial tissue
made of tall cells
54
connective tissue
underlies epithelial tissue
-has extensive extracellular matrix & few cells
55
extracellular matrix
an insoluble meshwork composed of proteins & polysaccharides
56
function of extracellular matrix
contributes structural support & provides informational cues that determine activity of cells it contacts
57
types of connective tissue
-basal lamina
-dermis
58
basal lamina
specialized connective tissue
59
dermis
made of cells that secrete the components of the extracellular matrix
60
characteristics of dermis
-strong and flexible bc it contains tough protein fibers
-contains blood vessels
-cushions the body
61
muscle tissue
made of cells called fibers that are able to shorten or contract
62
what are muscle fibers composed of
actin thin filaments & myosin thin filaments
63
myosin
a motor protein that uses ATP energy to change conformationally, which causes individual muscle cells to shorten, & the muscle tissue to contract
-only present in bilateraians
64
three types of muscle tissue in vertebrates
skeletal muscle, cardiac muscle, & smooth muscle
65
skeletal muscle
attaches to bone & controls voluntary movements
66
cardiac muscle
contracts to control the heartbeat
67
smooth muscle
found in the gut, where it causes waves of contraction that push food along the digestive tract, & blood vessels
68
nervous tissue
takes in sensory issue, processes info, & sends signals to target organs to elicit a response
69
organ system
combination of organs
70
sponge tissue characteristics
only have a simple epithelial lining
71
cnidarian tissue characteristics
have tissue diversity but no organs
72
bilaterian tissue characteristics
have true organs
73
zygote
fertilized egg
74
morula
ball of cells formed within 4-5 days after fertilization
75
early cell development stages
zygote -> 2-cell stage -> 4-cell stage -> morula -> blastocyst with inner cell mass -> gastrula with 3 germ layers
76
gastrula germ layers
ectoderm, mesoderm, endoderm
77
what does the ectoderm develop into
outer layer of the skin, brain & spinal cord, peripheral nerve cells, pigment cells
78
what does the mesoderm develop into?
inner skin layer, muscle, bone, blood
79
what does the endoderm develop into
inner gut lining & lung lining, liver, pancreas
80
blastocyst
hollow sphere that develops from the morula
81
inner cell mass
attached to the inside of the blastocyst wall & develops into the body of the embryo (pluripotent)
82
what happens to the blastocyst once it is developed
it implants in the uterine wall
83
gastrula
cells of the blastula become organized in the three germ layers
84
stem cells
totipotent, pluripotent, & multipotent cells
85
nuclear transfer
the nucleus of one cell is placed into the cytoplasm of another cell without a nucleus
86
regenerative medicine
aims to use the natural processes of cell growth & development to replace diseased or damaged tisses
87
how to create induced pluripotent stem cells (iPS cells)
activating a few genes in adult cells
88
signal transduction
an extracellular molecule acts as a signal to activate transmembrane proteins that, in turn, activate molecules
89
apoptosis
programmed cell death
90
necrosis
cell death that occurs in response to injury
91
proteases
enzymes that cleave proteins
-called caspases
92
cytoskeleton
structural protein networks in the cytoplasm that determine and maintain the shape of the cell
93
cell junctions
complexes of proteins in the cell membrane where a cell makes contact with another cell or the extracellular matrix
94
keratinocytes
specialized to protect the underlying tissues & organs
-elaborate system of cytoskeletal fibers
95
fibroblasts
synthesize the extracellular matrix
-strong & flexible
96
cytoskeletal elements
microfilaments, microfibers, and sometimes intermediate filaments (only in animal cells)
97
function of cytoskeletal elements
enable cells to change shape, move about, & transport stuff
98
microfilament
a double helix of actin monomers
99
intermediate filament
a strong fiber composed of protein subunits
100
microtubule
hollow tube formed from tubulin dimers
101
what protein makes up intermediate filaments in epithelial cells
keratines
102
what protein makes up intermediate filaments in fibroblasts
vimentins
103
what protein makes up intermediate filaments in neurons
neurofilaments
104
epidermolysis bullosa
a mutation in keratin genes that causes the intermediate filaments to not polymerize
105
how do protein subunits get longer
by adding subunits to their ends
106
plus end of a protein subunit
faster-assembling end
107
minus end of a protein subunit
slower-assembling end
108
dynamic instability
cycles of depolymerization & polymerization
109
motor proteins
small accessory proteins that allow microtubles & microfilaments to move
110
what motor proteins are associated with microtubule tracks
kinesin & dynein
111
kinesin function
transports molecules towards the plus end of microtubules
112
dynein function
transports molecules toward minus end of a microtubule
113
subunits of microfilaments
actin monomers
114
major functions of microfilaments
-cell shape & support
-cell movement
-cytokinesis
-vesicle transport
-muscle contraction
115
subunits of intermediate filaments
diverse
116
major functions of intermediate filaments
cell shape & support
117
subunits of microtubules
tubulin dimers
118
major functions of microtubules
-cell shape & support
-cell movement
-cell division
-vesicle transport
-organelle arrangement
119
type of cell junctions
-tight junction
-adherens junction
-desmosome
-hemidesmosome
-gap junction
120
primary function of a tight junction
epithelial boundary
121
what proteins are involved in the tight junction
claudins, occludins
122
does the tight junction attach to the cytoskeleton
no
123
primary function of the adherens junction
establish a physical connection among the actin cytoskeletons of cells in the epithelial layer
124
what proteins are involved in the adherens junction
cadherins, actin
125
does the adherens junction attach to the cytoskeleton
yes - microfilaments
126
primary function of the desmosome
cell-cell adhesion
127
what protein is involved in the desmosome junction
cadherins
128
does the desmosome junction attach to the cytoskeleton
yes - intermediate filaments
129
what is the main use for desmosomes
anchoring cells together while allowing food & waste to get through
130
primary function of hemidesmosome
connects cells to the basal lamina
131
what protein is involved in the hemidesmosome junction
integrins
132
does the hemidesmosome attach to the cytoskeleton
yes - intermediate filaments
133
primary function of the gap junction
communication between animal cells
134
what proteins are involved in the gap junction
connexions
135
does the gap junction attach to the cytoskeleton
no
136
microfilaments are composed of _____ in _____ arrangements
repeating actin subunits; a thin double-helix
137
microfilaments help a cell…
maintain its size & shape
138
cell movement can be facilitated by microfilaments in what way?
by dynamic growing & shrinking at the ends
139
which would be more likely to cause the development of a microvillus on an intestinal epithelial cell?
plus end growth of microfilaments at the tip of the microvillus but no shrinkage at the minus end
140
which best describes a role that microfilaments play in the structure and function of red blood cells?
they maintain the bioconcave shape to maximize gas exchange
141
microtubules form dimers of _____ and _____ subunits that polymerize into a ______.
alpha-tubulin; beta-tubulin; hollow tube
142
microtubules are _____ because they _____ and depolymerize at their ends.
dynamic; polymerize
143
the ability of microtubules to undergo rapid _______ and slower ______ is associated with the ability of the ______ to explore the cell and locate chromosomes
depolymerization; polymerization; spindle apparatus
144
microtubules can grow by the addition of tubulin dimers to ______, and they can shorten by the removal of dimers from ______.
both plus and minus ends; both plus and minus ends
145
the plus ends of both microtubules and microfilaments differentiate from the minus ends:
in that new tubulin or actin subunits are added more quickly
146
contraction of muscles is an example of how the motor protein _______ interacts with the cytoskeletal elements called ______ to produce movement
myosin; actin filaments
147
the basis for the movement of cilia and flagella is the interaction of the motor protein ______ with the cytoskeletal elements called _______
dynein; microtubules
148
when cells communicate by the signaling process, one cell produces a _______ that must be received by the ______ on or in the responding cell
signaling molecule; signal receptor
149
signal molecules that are _______ usually have their corresponding receptor ______ of the cell
polar; on the surface
150
a receptor that is inside the cell would require a _______ signal molecule that can ________ the plasma membrane
nonpolar; pass through
151
a ______ expresses a gene or genes that direct the production of the signaling molecule, and the ______ expresses a gene or genes that direct the production of the ______
signaling cell; responding cell; receptor protein
152
true/false: the ability of cells to adhere to each other is fundamental to multicellularity
true
153
many of the signaling pathways used for signaling between cells in complex multicellular organisms first evolved in…
unicellular eukaryotes
154
the ability of a specific tissue or organ to respond to the presence of a hormone is dependent on…
the presence of the appropriate receptors on the cells of the target tissue or organ
155
true/false: signaling pathways have been conserved in a wide range of organisms
true
156
true/false: a cell can only respond to signals from other cells, not from the physical environment
false
157
which signaling system involves the longest distance between release of a signaling molecule and activation of a receptor?
endocrine
158
kohler and lipton first discovered platelet-derived growth factors (PDGF) by observing that fibroblasts
grew better in cell culture containing blood serum containing proteins released by platelets during clotting
159
growth factors such as platelet-derived growth factor (PDGF) function in:
paracrine signaling
160
how do signaling molecules involved in paracrine and autocrine signaling travel?
by diffusion
161
what type of cell-surface receptor undergoes changes in phosphorylation in response to binding of its ligand?
a receptor kinase
162
true/false: most ligands form covalent bonds with their associated receptors, these complexes are more or less permanent and can only be broken through the hydrolysis of ATP
false
163
how does an “activated” receptor transfer information into the cell?
through a conformational change of the receptor
164
which type of protein adds a phosphate group to another molecule?
kinase
165
what is the end-result of activating the MAP kinase pathway?
a change in gene expression
166
the first step following platelet-derived growth factor (PDGF) binding of the receptor is
dimerization of the receptor
167
cells differentiate through
gene regulation
168
true/false: as cells differentiate, they lose their ability to become other cell types because they delete subsets of genes
false
169
cellular differentiation progressively restricts cell fate because the unexpressed genes in the cell:
-undergo irreversible repression
-become more densely packed with nucleosomes
170
signal transduction in development is often amplified by
sequential phosphorylation of proteins in the cytoplasm
171
signal transduction is the process by which
an extracellular molecule activates a membrane protein, which in turn activates molecules inside the cell
172
which tissue type is made up of cells that can contract?
muscle tissue
173
which tissue type can perform absorption or secretion in the body?
epithelial tissue
174
which tissue type helps form a barrier between the body and the external environment?
epithelial tissue
175
could melanin granules be moved by dynein and kinesin along an actin microfilament?
no, these motor proteins are specific to microtubules and cannot move along microfilaments
176
dynamic instability is a feature of
microtubules
177
myosin is a motor protein that associates with
microfilaments
178
which of the cell junctions is involved in creating a barrier between cells?
tight junction
179
cadherins bind to which type of cytoskeletal elements?
both intermediate filaments & microfilaments
180
what do gap junctions and plasmodesmata have in common?
they both allow direct transport of materials between cells
181
cadherins are
cell adhesion molecules found in cell junctions
182
what is the basal lamina?
a specialized form of the extracellular matrix found beneath all epithelial tissues
183
what is the extracellular matrix?
a network of proteins and polysaccharides outside the cell that play a role in structural support
184
the strength of collagen comes from
its triple helical structure & bundling
185
how do cells connect to the extracellular matrix?
through integrins
