Cell Communication & Differentiation Flashcards
Three ways cells communicate by signals by secreted molecules
Endocrine signaling ( sending molecules into bloodstream )
Paracrine signalling( molecules sent to other cells)
Autocrine signalling ( molecules secreted to own cell)
Describe signal transduction
Activation of specific receptor on plasma membrane by specfic ligand
After signal is received (reception), receptor activated and transmits signal into cell by series of switches and relay molecules
Leads to cellular response
What are different types of receptors
Ligand gated ion channels
G protein coupled receptor
Enzyme linked receptor
Function is to active intracellular switches
What occurs after activation of the receptor
Change in shape induces activation of enzymes that relay signal into cell
What occurs after enzyme linked receptors activated
Ligand binding and dimerisation
Enzyme activity on one receptor molecule helps phosphorylase and activate the other receptor molecule in the dimer
Chnage in receptor acts as a signal for other enzymes to be recruited to the receptor allowing the signal to be relayed to other enzymes which amplify the signal and pass it into to the cell
What do second messengers in a cell do
Amplify a weak signal so cell can respond rapid
What do kinases do
Grouo of enzymes that attach phosphate groups to a target protein
What do phophatases do
Class of enzymes that reverse phosphorylation by removing phosphate grouo
What is phosphorylation
Changes protein structure of target protein leads to a change in activity and acts as on off switch
What is protein phosphorylation
Post translational modification
Addition of negative charge from phosphate group to a protein can lead to conformational change
What proteins does protein phosphorylation typically occur on
Serine theonine tyrosine
What is a key property of second messengers
Small molecules that can diffuse rapidly across the cell
Importance of receptors being enzymes
Can produce lots of product in response to a signal and keep doing so consistently
Different type of stem cell
Totipotent - capable of producing any cell type
Pluripotent- capable of producing cells like ectoderm endoderm mesoderm( in blastocyst )
Multipotent- restricted set of cells
How do stem cells differentiate to differentiated cells
Receive differentiation signals telling them what type of cell to produce
Signals received by cell surface receptors that transmit signal into cell leading to changes in gene expression
Stem cells have multiple receptors that when one or more become activated starts differentiation
