gap junctions, cell-cell recognition
Name a ways in which cells communicate by direct contact.
plasmodesmata
An open channel in the cell wall of plants through which strands of cytosol connect from adjacent cells
gap junction
Points that provide cytoplasmic channels from one animal cell to another with special membrane proteins.
cell-cell recognition
Name a way in which cells communicate by indirect contact.
local signaling
signaling between adjacent cells
paracrine signaling
a secreting cell discharges local regulators into the extracellular fluid to target nearby cells
synaptic signaling
electrical signal along a nerve cell releases chemical signal in form of neurotransmitters and stimulates a cell across synapse
hormonal signaling
a type of long-distance signaling where an endocrine excretes hormones in a blood vessel to travel to a target cell
paracrine and synaptic signaling
What two types of signaling involve short range signaling?
hormonal signaling
What type of signaling involves long range signaling?
signal transduction pathway
A series of steps linking a mechanical or chemical stimulus to a specific cellular response.
small molecules, secreted proteins, membrane proteins
Name three types of signaling molecules.
benzaldehyde
small molecule used as a signaling molecule for smell
secreted proteins
EGF is an example of what type of signaling molecule? (small molecule, secreted proteins, membrane proteins)
secreted proteins and membrane proteins
Name the two types of secreted molecules that are classified as local signaling.
G protein
A membrane protein that is membrane-anchored, heterotrimeric, and involved in most signal transduction.
G-protein-coupled receptors
7 transmembrane proteins that can respond to a signaling molecule either on the surface or in the transmembrane space
conformation
Binding of signaling molecule changes what of the protein?
G protein
When signaling molecule is present, transmembrane protein bind to what?
GDP is replaced by GTP (phosphorylation)
When transmembrane protein binds to G protein, what happens?
activates it
Phosphorylating G protein does what to the protein?
phosphorylation (GDP -> GTP)
What actives the G protein?
activated enzyme
What inactivates G protein?
inactivated enzyme
After being activated, where does a G protein go to?
GDP
GTP is converted to what after being inactivated?
kinase
enzyme that phosphorylates itself or another protein
dimerized
When a protein is _________, it can phosphorylate itself?
dimerization
the process of bringing two individual receptor tyrosine kinase proteins together
signaling molecule
What causes dimerization to occur?
phosphorylation of each tyrosine group
Once dimerized, what activates the tyrosine-kinase protein?
6
How many phosphate groups does it take to activate receptor tyrosine-kinase protein?
6 ATP
How much energy does it take to activate receptor tyrosine-kinase protein?
relay proteins
Once activated, what attaches to tyrosine receptors?
relay proteins
A cellular protein that transfers a signal from a receptor molecule to another part of the cell
phosphorylation cascade
A series of enzyme-catalyzed phosphorylation reactions commonly used in signal transduction pathways to amplify and convey a signal inward from the plasma membrane.
ATP
WHere does the phosphate group come from in the phosphorylation cascade?
cyclic AMP
When ATP reacts with adenylyl cyclase, what is created?
adenylyl cyclase
An enzyme that converts ATP to cyclic AMP in response to a chemical signal.
pyrophosphate
When ATP reacts with adenylyl cyclase to create cAMP, what is released?
phosphodiesterase and water
WHat does cAMP react with to generate AMP?
AMP
When cAMP reacts with phosphodiesterase and water, what gets created?
adenosine monophosphate
What does AMP stand for?
adenylyl cyclase
Once G-protein is activated, it binds to what to make cAMP?
cAMP
WHen activated G-protein binds to adenylyl cyclase, what is produced?
cyclic AMP
A small, ring-shaped second messenger that activates protein kinase A.
cAMP, DAG, IP3, Ca2+
Name 4 signal molecules.
diacylglycerol
What does DAG stand for?
inositol triphosphate
WHat does IP3 stand for?
DAG
this second messenger is a lipid embedded in membrane
IP3
this second messenger is a small ring-shaped alcohol
phospholipase C
What cleaves PIP2 to create DAG & IP3?
signal molecule activates G-protein-linked receptor, activated G-protein-linked receptor activates G-protein, activated G protein activates phospholipase, activated phospholipase cleaves PIP2 to create DAG and IP3
Describe the steps in takes to create DAG and IP3.
PIP2
Phospholipase cleaves what to create DAG and IP3?,
Phosphatidyl Inositol Biphosphate
WHat does PIP2 stand for?
DAG
After cleaving PIP2, this second messenger functions in other membrane pathways
IP3
After cleaving PIP2, this second messenger quickly diffuses through the cytosol and binds to a gated calcium channel in the ER membrane, causing it to open.
IP3-gated calcium channel
Where does IP3 bind to after being created from PIP2?
channel opens and calcium ions flow out of the ER into cytosol
When IP3 binds to the gated calcium channel, what happens?
down
WHen calcium ions flow out of the ER, are they flowing down or up the concentration gradient?
transduction
the process of relaying a signal
response
the overall effect of signal
epinephrine
A hormone responsible for fight or flight response.
epinephrine
this hormone signals via G protein
glycogen
What is the overall metabolic product when epinephrine binds to G-protein-linked receptor?
bloodstream for glycolysis
Once phosphorylated, glucose can be delivered to where for what?
amplification of signal
What is the advantage of the multiple step epinephrine signaling transduction?
10^6 molecules
What is the amplification of signal in the case of epinephrine? 1 molecule to what?
slower than neuron signaling
What is the disadvantage of the multiple step epinephrine signaling transduction?
slower
Long range hormonal signaling elicits a slower or faster response?
hormonal signaling
this type of signaling involves the receptor performing the signal transduction and transcriptional response
hormonal signaling
This type of signaling does not need signal transduction pathway
lipiphilic
Why can steroid hormones cross the membrane?
1) hormone passes through membrane
2) hormone binds to receptor protein in cytoplasm and activates it
3) hormone-receptor complex enter nucleus and binds to specific genes
4) bound protein stimulates transcription of the gene into mRNA
5) mRNA is translat
Name the steps of hormonal signaling.
male and hermaphrodite
What are the two sexes of C. elegans?
self-fertilization
WHat can a hermaphrodite C. elegan do that a male cannot?
anchor cells
these cells organize vulval cell formation through signal proteins and cause pattern of division
inner and outer
Name the two types of vulva cels.
inner vulva cells
these cells get the largest dose of anchor cell signal protein during vulva formation
outer vulva cells
these cells get the smaller dose of anchor cell signal protein during vulva formation
epidermal cells
these cells get no dose of anchor cell signal protein during vulva formation
vulval precursor cells
these cells are just skin cells but are ready to be changed into vulva cells
larva stage
During what stage of C. elegans development does vulva development occur?
multivulva
mutations that cause too much anchor cell signaling results in this type of C. elegan
vulvaless
mutations that result in no anchor cell signaling results in this type of C. elegan
Ras protein
A type of G protein that is activated by binding of signaling molecules to receptor tyrosine kinases and then initiates a phosphorylation cascade, culminating in a cell response.
raf kinase
Initial kinase in a kinase cascade following activation of ras
receptor tyrosine kinase protein and Ras protein
vulva signaling from anchor cells to vulva precursor cells happens via what 2 proteins?
epidermal growth factor
What does EGF stand for?
epidermal growth factor
WHat is the signal protein coming from the anchor cell?
epidermal growth factor receptor
What does EGFR stand for?
ras G protein
What starts phosphorylation cascade in vulva signaling?
MEK kinase and MAP kinase
AFter raf kinase is activated, what other two enzymes are activated in transduction pathway of vulva formation?
ETS transcription factor
After MAP kinase, what transcription factor is activated?
transcription factor
A regulatory protein that binds to DNA and affects transcription of specific genes.
lin-3
In vulva development signal transduction, what is the specific signal?
let-23
In vulva development signal transduction, what is the specific receptor?
let-60
In vulva development signal transduction, what is the specific ras G protein?
lin-1
In vulva development signal transduction, what is the specific transcriptional change?
lin-45, mek-2, mpk-1
In vulva development signal transduction, what is the specific phosphorylation cascade?
repressor to release from promotors
phosphorylation of lin-1 causes what to happen?
lin-1
Phosphorylation of what causes repressor to release from promotors?
apoptosis
Programmed cell death
ced-9
gene that blocks apoptosis by disabling ced-4
ced-9
mutation at this gene causes all cells to die
ced-3 and ced-4
mutations at these genes prevent cells form dying
Bob Horvitz
leading researcher in the field of apoptosis
laminin
Extracellular matrix glycoprotein that holds nucleus together
caspase
a family of cysteine-dependent, aspartate-specific proteases that are associated with apoptosis in neurodegenerative diseases
cysteine and aspartate
what two amino acids proteases are associated with caspase?
FasR
Death receptor for the extrinsic pathway of apoptosis
mitochondrial membrane
Where is ced-9 protein?
FasL
death signaling molecule that will attach to FasR to activate apoptosis
FasL binds to FasR, FasR inactivates ced-9, inactivated ced-9 cannot inactivate ced-4, activated ced-4 activates ced-3, activated ced-3 activates other proteases and nucleases, activated proteseases cleave laminin
Describe the steps that cause apoptosis? start with FasL.
Bcl-2
this human gene is the same as the gene ced-9 in C. elegans
Mating type a secretes a signal called a factor.
Which of the following is true of the mating signal transduction pathway in yeast?
a) The signal reception, transduction, and response occur in the nucleus.
b) Mating type a secretes a signal called a factor.
c) The pathway carries an electrical signal be
the active site of an enzyme in the cytoplasm that binds to a specific substrate.
Of the following, a receptor protein in a membrane that recognizes a chemical signal is most similar to:
a) an enzyme with an optimum pH and temperature for activity.
b) genes making up a chromosome.
c) RNA specifying the amino acids in a polypeptide.
d)
binding with a receptor protein that enters the nucleus and activates specific genes.
Testosterone functions inside a cell by:
Selected Answer:
a) acting as a steroid signal receptor that activates ion-channel proteins.
b) acting as a signal receptor that activates ion-channel proteins.
c) becoming a second messenger that inhibits adenylyl
GTP
Which of the following is not considered a second messenger?
a) GTP
b) calcium ions
c) inositol trisphosphate
d) diacylglycerol (DAG)
e) cAMP
receptor tyrosine kinases
The receptors for a group of signaling molecules known as growth factors are often:
a) cyclic AMP.
b) ligand-gated ion channels.
c) G-protein-linked receptors.
d) receptor tyrosine kinases.
e) neurotransmitters.
GTP donates a phosphate group to an inactive protein kinase.
Which of the following is not part of the phosphorylation cascade model?
a) A specific protein is activated via phosphorylation.
b) GTP donates a phosphate group to an inactive protein kinase.
c) A cellular response is initiated.
d) Protein kinase is acti
ras G protein
Which one of the following is a membrane-anchored protein?
a) integrin
b) EGF receptor
c) ATP synthase
d) ras G protein
e) epinephrine receptor