Chapter 11- Cell Comunication Flashcards
How do cells identify their sexual mates?
through chemical signaling
What are the two sexes called
a and squiggly a
what is a synonym for two sexes
mating types
what makes the two mating types different
they each secrete a specific factor that only binds only to receptors found on the other type of cell
what happens when the cells are exposed to each other’s mating types
the cells change shape, grow towards each other, and fuse (mate_
What traits does the new cell have after mating
the new cell contains all the genes of both original cells
Why is it beneficial for the new cell to have genes from both original cells
a combination of genetic resources provides advantages to the cell’s descendants, which arise by cell divison
Why is there unique matching between mating factor and receptors
KEY INFO
to ensure mating only among the same species .
How does the binding of a mating factor by the yeast cell surface receptor initiate a signal that brings about a cellular response in mating?
signal transduction pathway
Is cell signaling important among prokaryotes?
OUI (yes sirrr)
quorum sensing
sending the concentration of signaling molecules allows bacteria to monitor their own local density
example of quorum sensing…
biofilm
what is biofilm
aggregation of bacterial cells that adhere to a surface
FIrst type of cell to cell communication
DIRECT CONTACT
what type of cells have direct communication??
EUKARYOTIC CELLS
plant and animal
what does direct communication use?
Cell junctions
gap junctions in animals
plasmodesmata in plants
In regard to direct communication, what can animal cells do that plant cells cannot…
cell-cell recognition( also type of local signaling)
when is cell-cell recognition important
embryonic development and in the immune system response
in most Local Signaling cases…
signaling molecules are secreted by the signaling cells
local signaling in animals is called
paracrine signaling
a more specialized type of local signaling is called
SYNAPTIC SIGNALING
where does synaptic signaling occur
animal nerous system
describe synaptic signaling
an electrical signal along the nerve cell triggers the secretion of neurotransmitter molecules. These molecules act as chemical signals that diffuse across the synapse triggering a response in the target cell
Long Distance signaling usually utilizes
hormones
what is hormone signaling in animals known as
endocrine signaling
three steps of cell communication
reception
transduction
response
reception is when
the target cell detects a signal molecule coming from outside the cell. once it is detected the signal molecule binds to a receptor protein located at the cells surface or inside the cell
Transduction is
the conversion of the signal to a form that can bring about a particular cellular response
is transduction a single path
IT IS BOTH, can be a single path or can be signal transduction pathway
usually requires more than one step
what are the molecules in the pathway of signal transduction pathway called
relay molecules
reponse…
is when the transducted signal finally triggers a response
the response can literally be anything imaginable cellular activity
reception of a signal
depends on the receivor
por ejemplo: yeast a cells mating signals are only heard by prospective squiggly a yeast cells
signaling molecule acts as a
ligand
what is a ligand
a molecule that specifically binds to another molecule
Ligand binding usually causes
receptor protein to undergo shape change
what are the three types of transmember receptor proteins
G protein-coupled RECEPTORS
Receptor Tyrosine Kinases
Ion Channel Receptors
when GDP is connected with G protein what state is it in
inactive
when signal molecule binds to extracellular side of receptor…
the receptor is activated and changes shape , The cytoplasmic side then binds to the inactive protein and activates it by converting GDP to GTP
Once the G-protein is activated what happens
it detached from receptor and attached to enzyme which activates the enzyme and changes its shaped, which hydrolizes GTP into GDP
What is a difference between RTKs and GPCRs
RTKs can activate many pathways while GPCRs can usually activate only one transduction pathway
in RTKs what are the proteins called when they are inactive
monomes
what does each monomer have
ligand binding site, alpha helix spaning the membrane and an intracellular tail containing multiple tyrosines
The binidng of the signal molecules inRTKs causes the two receptor monomers to combine to form
a dimer
the process where it becomes a dimer is caused
dimerization
Dimerization activates the tyrosine kinase region which then causes
every tyrosine to attach to an atp and take a phosphate which then cause an relay protein to come and take phosphate and become activated
Where are ligate gated ion channels especially important
nerve cells / functioning of nervous system
cell surface receptors tend to be
flexible and inherently unstable, and thus difficult to catalyse
protein kinase
an enzyme that transfers phosphate groups from ATP to a protein
what are protein phosphatases
enzymes that can rapidly remove phosphate groups from proteins, dephosphorylation
second messengers
small nonpolar, water soluble molecules or ions that are components of signal transduction
two most commonly used second messengers
calcium and cyclic AMP
Camp is made by
Atp by adenylyl cyclase(embedded in plasma membrane)
HOW MANY phosphates does atp and camp have
3
1
concentration of signal will impact
determine impact of signal
one signal can have ….
many different responses
police to crime vs students to crime
cholera does what to CAMP
increases CAMP in cell which causes ions to leave cells which then causes water to leave cell causing fatal diarrhea
what are the TWO possibilities for a cellular response
turn on or off gene or protein
calcium is regulated where
kidney
proximal and distal tubules
calmodulin…
WILL HAVE FOUR CALCIUM IONS BIND TO IT WHICH CHANGES ITS SHAPE
CALMODILIN DOES WHAT…
activate other enzymes gives hug
how doex calmodulin change other protein’s shape
it hugs them wraps around
