quiz 5 Flashcards
(200 cards)
1
Q
What are the three ways cells can communicate with each other
A
direct contact, local signaling, and long distance signaling
2
Q
what are the three steps (in order) that target cells process the signal
A
reception, transduction, response
3
Q
what is a ligand
A
the signaling molecule
4
Q
Ligands bind to what on the target cell
A
receptor proteins
5
Q
receptor proteins can be where in the cell
A
on the plasma membrane or within the cell
6
Q
if the ligand is polar and hydrophillic, where will the receptor protein be on the target cell
A
on the plasma membrane/embedded in the plasma membrane
7
Q
if the ligand is nonpolar and hydrophobic, where will the receptor protein be on the target cell
A
in the cytoplasm
8
Q
how is communication between cells done through direct contact (in other words, describe direct contact communication)
A
molecules on surface of one cell are recognized by receptors on the adjacent cell. An example is gap junction
9
Q
what is moved in between cells during direct contact . And do those molecules go through the plasma membrane? why or why not
A
ions and small molecules move through gap junctions and don’t go through the plasma membrane b/c they go through the gap junction
10
Q
How does direct contact work with plants?
A
ions and small molecules move through the plasmodesmata
11
Q
How is local signaling different from the other types of cell communication
A
local signaling is communication with nearby cells
12
Q
what are the 3 types of local signaling
A
paracrine signaling, autocrine signaling, and synaptic signaling
13
Q
describe paracrine signaling
A
signal released from secretory vesicle and diffuses through the extracellular fluid to the receptors of target cells.
14
Q
what is autocrine signaling and where are the receptor proteins
A
cell communication by local signaling where the target cell is itself and the receptor proteins are on itself
15
Q
what is synaptic signaling
A
electrical signal triggers release of neurotransmitters to a adjacent neuron
16
Q
what is the area where the target neuron in synaptic signaling called
A
synapse
17
Q
what is the neuromuscular junction and what type of local signaling is it
A
the synapse between a neuron and its muscle fiber and its synaptic signaling
18
Q
in long distance signaling, what is another term for the ligand
A
hormone
19
Q
in animals, long distance signaling travels through what
A
circulatory system, through the blood
20
Q
in plants, hormones are in what form and travel through what medium and to what
A
gases through the air to target tissue
21
Q
what is reception, also are receptors specific? and specific to what?
A
the binding of a signal molecule with a SPECIFIC receptor on a target cell. Receptors are specific to signal molecules
22
Q
name an example of a polar signal molecule/ligand
A
epinephrine
23
Q
name an example of a non polar signal molecule/ligand
A
steroid hormones
24
Q
what is transduction
A
the events within a cell that occur in response to a signal. Changes signal into a form that causes a cellular response
25
what is the first thing that happens to the receptor when the ligand/initial signal activates it
the receptor undergoes conformation change
26
what is initiated thanks to the receptor protein changing when activated
a signaling cascade
27
what is response
transduced signal causes a specific cellular response
28
what 2 factors change the type of response a cell will do
the signal and the receptors on the target cell
29
what did we find out in sutherland's work
response was activation of the enzyme glycogen phosphorylase
30
when the ligand binds to the receptor protein, does the ligand undergo a conformation change
no
31
are receptors specific
yes
32
do receptors only bind to one type of signal molecule
yes and sometimes to a closely related group of signal molecules
33
does the receptor ligand complex directly or indirectly interact with a whole host of other signaling molecules within the cell
both directly or indirectly
34
what allows cells to react separately to hormones and growth factors circulating in extracellular fluids
the fact that different cell types contain distinct combinations of receptors
35
is the combination of surface receptors on cell types fixed?
no, it changes as cells develop
36
are there changes when normal cells transform into cancer cells?
yes
37
what are the 3 subclasses of membrane receptors and describe each of them
channel linked receptors- ion channel that opens in response to a ligand
Enzymatic receptors- receptor is an enzyme that is activated by the ligand
G protein couple receptor GPCR- a g protein that assists in transmitting the signal, also is bounded to GTP
38
name an example of an enzymatic receptor
receptor tyrosine kinase
39
what are the two types of G proteins and what are the difference and simliarities
Ras and Trimeric G protein
Ras is monomeric while Trimeric has 3 subunits, alpha beta and gama
both of them bind GTP in their active form and bind GDP in inactive form
40
Guanine nucleotide in GTP binds to which subunit in trimeric g protein
alpha subunit
41
explain the name GPCR
there is a receptor that binds to the g protein (either trimeric or ras)
42
what turns on the g protein
the receptor attached to it
43
An activated G-protein activates what and is it membrane bounded
an effector protein, usually an enzyme, that is membrane bounded
44
what is the first messenger usually
the ligand/signal molecule
45
how does a G protein change from attaching a GDP to GTP?
GDP is kicked off and GTP binds to the activated G protein
46
What happens to the GTP bound subunit after being activated by the ligand
it breaks off and binds to the plasma membrane associated enzyme, aka the effector
47
How does the G-protein subunit inactivate itself
by hydrolyzing GTP to GDP
48
what does the activated effector generate
nonprotein signal molecules called second messengers
49
Are second messengers proteins?
no
50
second messengers directly/indirectly activate what
protein kinases
51
what do protein kinases do in transduction
they initiate a cellular response by phosphorylating specific target proteins
52
what happens to the beta and gamma subunits after detaching from the alpha subunit
it binds itself to the plasma membrane and goes away
53
are second messengers signaling molecules
yes
54
what is the common single cell model used for cell cycle research
Saccharomyces Cerevisiae or S. Cerevisiae
55
why is S. Cerevisiae a good model organisms for cell cycle research (4)
because it has many cells that can be easily visualized
cell cycle can be paused at a specific phase
all cells can be synchronized at one phase
mutations are easily generated
56
what are the two irreversible points of the cell cycle
replication of genetic material and separation of the sister chromatids
57
what are checkpoints
places where the cell cycle can be put on hold to check for accuracy
can be halted if there are errors
58
what allows cells to respond to internal and external signals
checkpoints
59
what are the 3 checkpoints in cellc cylce
G1/S
G2/M
Mitotic spindle checkpoint
60
what do we do to checkpoints to proceed the cell cycle
we have to inactivate the checkpoint
61
Which checkpoint is the primary point for external signal influence
G1/S checkpoint
62
which checkpoint does the cell "decide" to divide
G1/S
63
Which checkpoint assesses the success of DNA replication
G2/M
64
which checkpoint makes the commitment to mitosis
G2/M
65
What is another name for the mitotic spindle checkpoint
Late metaphase checkpoint
66
Which checkpoint ensures that all chromosomes are attached to the spindle
spindle checkpoint
67
is the cell cycle a true cycle and what is a true cycle
yes and it means it is not reversible
68
is the cell cycle under genetic control
yes
69
when are genes transcribed when their products are needed
during the cell cycle right before theyre needed
70
what has helped identify the key regulatory pathways
mutations
71
What can arrest a cell at the G1/S checkpoint (2)
DNA is damaged by radiation or chemicals
| if the cell is nutritionally deficient or growth factors are absent
72
what can deactivate the G1/S checkpoint if the reason for its arrests is DNA damage
DNA is repaired then the cycle starts again
73
When can a cell be arrested in G2/M
DNA was not replicated accurately in S phase or DNA damage by chemicals or radiation
74
What is assessed at the Mitotic spindle checkpoint
whether chromosomes are attached properly to the mitotic spindle so that they align correctly at the metaphase plate
75
Once the cell begins anaphase it is _____ _____ to completing M
irreversibly committed
76
What protein and enzyme (respectively) are involved in the internal control system of cell cycle
cyclins and Cyclin dependent kinases (CDKs)
77
When are Cdk enzymes active
when it is bound to cyclin
78
when does a cdk become inactive
when the cyclin binded to it is degraded
79
Phosphorylation regulates proteins that do what in cell cycle
initiate or regulate key events in cell cycle (DNA replication, mitosis and cytokinesis)
80
what cyclin and CDK is in G1/S and when does it bind to each other. Also this regulates the transition from what phase to what
G1/S cyclin binds to CDK2 near the end of G1. required for transition from G1 to S and to commit DNA replication
81
What cyclin and CDK is in s phase and what is it required for
S cyclin binds to CDK2 and is required for initiation of DNA replication and progression of the cell through S
82
what cyclin and CDK is in G2 and is required to transiton from what phase to what phase
M cyclin binds to CDK1 and transition from G2 to M
83
what CDK does G1 cyclin bind to before the G1/S transition and how many cyclin-CDK complexes does it form. Also what are these complexes used for
CDK4 and CDK6 and 2 cyclin-CDK complexes. They are needed to move the cell through the G1 checkpoint and proceed from G1 to S
84
What is another name for M cyclin-CDK 1 complex called
M phase-promoting factor (MPF)
85
MPF activates which enzyme and when does it happen
when chromosomes are correctly attached to the mitotic spindle, MPF activates anaphase promoting complex (APC)
86
what does activated APC do
degrades an inhibitor of anaphase which leads to separation of sister chromatids, and later APC degrades M cyclin, causing CDK1 to lose activity
87
when does the G1/S cyclin fully degrade? (in what phase) When does it bind together to make the cdk complex
S phase and it is binded in the G1 phase
88
when is the S cyclin-CDK complex formed and when is the cyclin completely degraded
is formed at the G1/S checkpoint or at the beginning of S-phase and degrades in G2
89
when is the M cyclin-cdk complex made (in what phase) and when is the cyclin completely degraded
formed in late S phase and degrades in Mitosis
90
What are CDKs
cyclin dependent kinases. Enzymes that phosphorylate proteins
91
What is the primary mechanism of cell cycle control, or what drives the cell cycle?
CDKs
92
What controls CDK
phosphorylation
93
does phosphorylation activate or inactivate CDK
both. CDK has 2 sites for phosphorylation, one site for activating it and one site that inactivates it
94
Desccribe Johnson and Rao's experiment and its result
Fused 2 different HeLa cells at different stages of the cell cycle,G1 and S and G1 with M. Results show that the G1 cell quickly moved onto the stage of the other cell which proves molecules in the cytoplasm control the cell cycle.
95
Name some external controls for cell growth
peptide hormones and growth factors
96
Reactions triggered by the activated receptor of a cell may ___ ____ or ___ the progress of cell divison
speed, slow, or stop
97
What is contact inhibition
The cell surface receptors on cells recognize contact with other cells and will inhibit division
98
Contact inhibition causes cells to be shunted into what phase? And how would they recover out of this stage
G0 and will divide once contact with other cells are broken
99
Which cell responds to a greater variety of external signals, animal cells or yeasts
animal cells
100
More complex control means more CDKs in eukaryotic cells which means more what?
input into control of the cycle, basically more control
101
what is cancer's most basic definition
uncontrolled cell division
102
what is a tumor
rapidly growing mass of cells
103
what is metastasis
when cancer cells spread throughout the body and produce new tumors in other regions
104
Metastasis is promoted by what? (3)
changes that block contact inhibition
alter cell surface molecules that link cells together
accumulation of mutated genes
105
mutated genes for components of the cyclin/CDK system leads to what
cancer
106
what are oncogenes
mutated form of genes
107
describe Gorbsky experiement and its results
Gorbsky died a portion of the kinetochore microtubules and during anaphase the dyed segment didn't move which mean the the chromosomes were moving by sliding along the microtubule
108
what did gorbsky's experiment prove
kinteochore microtubules are not pulling the cohesin protein apart
109
mitosis evolved from what?
binary fission
110
T/F phosphorylation only activates proteins
false, it can inactivate proteins
111
what is the difference between kinase and phosphatase
kinase adds a phosphate to a protein from ATP
| Phosphatase removes a phosphate from a protein
112
What are the two classes of kinases we need to know for protein phosphorylation? With kinase, what is removed and what is attached
Ser/Thr kinase and Tyrosine kinase. The alcohol group is removed and a phosphate group is added
113
do kinases in a phosphorylation cascade catalyze phosphorylation of another kinase?
yes
114
in a phosphorylation cascade, is the prior protein kinase deactivated by donating its phosphate group to the next protein kinase?
no, it stays active
115
what is it called for the last protein in a phosphorylation cascade
target protein
116
what does cAMP stand for and it is derived from what
cyclic AMP that is derived from ATP
117
what is the effector that produced cAMP
adenyl cyclase
118
does cAMP diffuse through cytoplasm or stay attached to the membrane
diffuse through the cytoplasm
119
What does IP3 and DAG stand
inositol triphosphate and diacylglycerol
120
what is the effector that produced IP3 and DAG and how does it make those second messengers
phospholipase C and it makes IP3 and DAG by breaking down a membrane phopholipid
121
is IP3 water soluble? does it diffuse through the cytoplasm?
yes and yes
122
is DAG hydrophobic? Where does it stay
yes its hydrophobic and it remains and functions in the plasma membrane
123
is cAMP found in animals and fungi? is it found in plants? if so what is its function
yes and yes and yes and its for germination or defensive responses in plants
124
what are some cellular responses that cAMP controls (5)
```
uptake and oxidation of glucose
glycogen breakdown or synthesis
ion transport
transport of amino acids into cell
cell division
```
125
Glucagon triggers a ___ receptor in what organ and what is the response
glucagon triggers a cAMP receptor in liver cells which stimulates them to break down glycogen into glucose units
126
which protein kinase does cAMP activate
protein kinase A
127
which second messenger pathway are universal among eukaryotic organisms
IP3/DAG second messenger pathway
128
what kind of responses does the IP3/DAG pathway control?(4)
sugar and ion transport
glucose oxidation
cell growth and division
smooth muscle contraction
129
in (animal or plant) cells, IP3 activates transport proteins in the (what organelle) that release (what ion) into the cytoplasm, which activates a protein kinase cascade
in animal cells, IP3 activate transport proteins in the ER that release Ca2+ into the cytoplasm which activates a protein kinase cascade.
130
how does phospholipase C make DAG and IP3
cleaves membrane phospholipid PIP2 to produce IP3 and DAG
131
What is the target protein in the IP3/DAG pathway and which second messengers directly activate it
protein kinase C is activated by DAG and Ca2+
132
can different receptors produce the same second messengers ? if so name an example
yes, epinephrine and glucagon
133
describe the signal transduction pathway of epinephrine and glucagon
both ligands attach to the GPCR on the surface of the cell and activates the Gprotein to bind to GTP and activate adenyl cyclase to make cAMP from ATP
cAMP binds to protein kinase A then phosphorylates phosphorylase kinase which phosphorylates glycogen phosphorylase which phosphorylases glycogen to glucose 6 phosphate
134
describe sutherlands experiemental research and its results
centrifuges liver tissue with the pellet containing the cell membrane and the cytoplasm After adding epinephrine we found a second messenger produced then adding the supernatant, active glycogen phosphorylase was detected. Results show enzyme activation did not directly involve epinephrine but required another cellular factor (the second messenger)
135
What is part of a bacterial 2 component signaling
surface receptor protein and intracellular response regulator
136
what are the steps of bacterial 2 component signaling (3)
signaling molecule binds and activates surface receptor
surface receptor phosphorylates and activates response regulator
response regulator binds to regulatory sequences in DNA which turns genes on and off
137
did cell signaling exist in unicellular organisms?(before multicellularity)
yes
138
what is quorum sensing and what kind of cells have it
bacteria release signal molecules in increasing concentration as cell density increases and each cell then responds to adapt to changing environment
139
how does sexual mating occur in unicellular eukaryote
sexual mating begins when one cell secretes hormone that is recognized by a cell of different "sex"
140
when did protein kinases appear in cell communication?
after eukaryotes evolved
141
what does a pathway for cell growth control between a fruit fly (drosophilia) and a human indicate?
this pathway is at least 800 million years old
142
Mickey hayes and Fransie Geringer had what disease?
Progeria
143
children with progeria die at an old age of what
13
144
what is the cause of progeria
error in gene lamin A
145
what is lamin A and where is it
lamin protein that reinforces inner surface of nuclear envelope in animal cells
146
what animal did Thomas Hunt Morgan cultivate to study genetics
drosophila melanogaster or fruit flies
147
what was discovered in the fly room
sex linked genes and sex linkage
148
what animal was chosen to be the model for the human genome project
fruit flies
149
What is true breeding
breeding between a homozygous dominant and homo recessive
150
what were the dominant and recessive phenotypes in fruit flies
dominant was red eyes with normal wings and recessive were purple eyes and vestigial wings
151
what is a testcross
breeding between a homozygous recessive and a suspected heterozygous
152
in a testcross with Morgan's fruit flies, what were the results and from those results what can we determine
an higher amount of parental phenotypes in F2 and lower number of recombinants when the expected outcomes were 25% of each combination. These results show that there is gene linkage in genes on the same chromosome and the distance from each other
153
what is genetic recombination
2 homologs of nonsister chromatids exchange segments during meiosis
154
what is the relationship of frequency of recombination and distance
more recombination frequency means theres more distance between the genes
155
what does progeny mean
offspring
156
Pr+ pr vg+ vg, how many different types of gametes can be produced. How many chromosomes is given?
4 different types of gametes, 2 chromosomes and diploid
157
how do you calculate recombination frequency
(recombinants/total progeny)*100= percent
158
what is a linkage map
shows relative locations of genes
159
what are the two units for linkage map and what is it equivalent to in terms of recombination frequency
map unit (mu) and centimorgan(cM) and 1 mu=1 cM= 1% recombination frequency
160
can we still show linkage between genes that are widely separated and show a high recombination frequency? if so, how?
yes, we find the recombination frequency of a gene inbetween them
161
what does it mean for gene to assort independently
when genes are so likely to undergo recombination
162
T/F some of the genes Mendel studied assort independently, even though they are on the same chromosome
true
163
what are the three most common modes of inheritance
autosomal recessive, autosomal dominant, x linked recessive
164
how many autosomes do humans have
22
165
pedigree analysis is used to track what?
inheritance patterns in families
166
is juvenile glaucoma dominant or recessive? Also what is juvenile glaucoma
dominant and disease that causes degeneration of optic nerve leading to blindness
167
name 3 important things in a dominant pedigree
Heterozygotes exhibit the affected phenotype
males and females are equally affected and may transmit the trait
affected phenotype does not skip generation
168
is achondroplasia an autosomal dominant or recessive trait and describe the disease
dominant and its dwarfism (lack cartilage formation)
169
name 3 important things in a recessive pedigree
Heterozygotes exhibit the affected phenotype
males and females are equally affected and may transmit the trait
may skip generation
170
what is the difference between affected and carrier
affected has 2 recessive genes and shows the phenotype while carrier does not show the phenotype
171
is albinism recessive or dominant
recessive and cannot produce melanin
172
can affected individuals of recessive genes have unaffected parents
yes, both would be carriers
173
is PKU a recessive or dominant trait and what is PKU
phenylketonuria is an autosomal recessive trait and its when the bodies build up amino acid phenylalanine
174
what are other modes of inheritance that are not common (3)
x linked dominant, y linked, mitochondiral
175
what are sex linked genes
genes located on sex chromosome
176
females have how many copies of the x chromosome? forming a ____ pair
2 copies forming a homologous XX pair
177
males have how many x and y chromosomes, which means they have an __ combination
1 copy of X and 1 copy of Y so an XY combination
178
what is a homogametic sex
XX females produce only one type of gamete (X)
179
what is a heterogametic sex
XY males produce two types of gametes (X and Y)
180
what happens when a sperm carrying an X chromosomes fertilizes an X bearing egg cell
individual develops into an XX female
181
what happens when a sperm carrying an Y chromosome fertilizes an X bearing egg cell
individual develops into an XY male
182
what is sex linkage
alleles on sex chromosomes
183
Ducheene muscular dystrophy is an X linked ___ trait. What would this pedigree look like
x linked recessive trait, and the pedigree could skip female generations and mostly affect males
184
enamel hypoplasia is an X linked ___ trait, what would this pedigree look like
x linked dominant trait, and this pedigree would affect a female every generation
185
which gene on the y chromosome determines human sex
SRY gene
186
in early embryonic development, are the reproductive organs different in XX and XY embryos
no, they are the same
187
when the SRY gene is active, what is developed
testes
188
hormones from testes do what to female structures and to male structures
degenerate tissues for female structures and develop tissues for male strucutres
189
what are chromosomal mutations
changes in chromosome structure or chromosome number
190
What are the 4 possible changes in chromosome structure and describe each of them
Deletion- segment lost from chromosome
duplication- segment is broken from one chromosome and inserted into its homolog, adding to the ones already there
(Reciprocal)Translocation- segment is attached to a different non-homolog
inversion-segment reattaches in a reversed orientation
191
what is nondisjunction
failure of homologous pairs to separate during the first meiotic division or chromatids in the second meiotic division
192
what is the difference between euploids and aneuploids
euploids are individuals with a normal set of chromosomes and aneuploids are individuals with extra or missing chromosome
193
nondisjunction in meiosis 1 leads to daughter cells with what ploidy
2 cells with n+1 and 2 cells with n-1
194
nondisjunction in meiosis 2 leads to daughter cells with what ploidy
2 cells with n, 1 cell with n+1 and 1 cell with n-1
195
down syndrome aka?
trisomy 21, extra copy of chromosome 21
196
downs primarily occurs in what gender and increases with what
female and increases with maternal age
197
what is the easiest way to diagnose downs syndrome
a karyotype is taken to see the chromosomes
198
what is a consanguineous marriage and how is it represented in a pedigree
marriage between first cousins, double lines on pedigree
199
is DAG hydrophobic or hydrophillic
hydrophobic
200
connexon proteins is affiliated with what type of signaling
direct contact
