CH 9 Cell Communication Flashcards Preview

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Flashcards in CH 9 Cell Communication Deck (22):

What are the four steps of cell signalling?

Receptor activationSignal transductionResponseTermination


Define receptor activation

The signal nods to a receptor which is then activated


Define signal transduction

Signal is transmitted to the interior of the cell by a signal transduction pathway


Define response

Cell responds for example by activating an enzyme or turning on transcription


Define termination

The response is terminated so that new signals can be received


What is the most important factor for communication in bacterial cells?

The number of cells (cell density)


What are the four types of signalling and how far does the signal travel?

Endocrine - large distancesParacrine - up to 20 cellsAutocrine - cell is the signalling and responding cell (self)Juxtacrine - direct physical contact


During endocrine signalling how is the signalling molecule transmitted?

Though the circulatory system


Why do Paracrine signalling cells not signal themselves?

They do not contain receptors


Does juxtacrine signalling cause a confirmational change ?



Define ligand

Signalling molecule


Define ligand binding site

Location on the receptor to which the ligand binds


Polar molecules require which type of receptors to communicate?

Cell surface receptors


Non Polar molecules require which type of receptors to communicate?

Intracellular receptors


What are the three types of cell surface receptors?

G protein coupled receptorsReceptor kinasesLigand gated ion channels


How are ions able to pass through ligand-gated ion channels?

Confirmational change, changes the shape of the ion channel to allow ones to pass through


What are the three phases of G protein activation?

Alpha subunit is joined by three subunits and G protein is inactiveG protein gets bound by an activated receptor causing GDP to turn into GTP therefore activating the proteinActivated G proteins binds and activates target protein


Explain the amplification of the adrenaline signal

Each activated receptor activates multiple G proteins which activates adenylyl Cyclase enzymesEach adenylyl Cyclase enzyme produce cAMP which activates protein kinase AEach protein kinase A activates multiple protein targets


Explain termination of the G protein signal

Signal molecule detaches from the receptor after a certain amount of timeGTP is converted back to GDP in the G protein Enzymes in cytosol degrade cAMPPhosphotases removes phosphate groups from proteins causing them to become in active


Explain receptor kinase activation and signalling

Signalling molecules bind to receptor causing a confirmational changeThis creates a dimer Each member of the receptor pair attaches phosphate groups to the other member The phosphate groups provide binding sites for intracellular signalling proteins


Explain the MAP kinase pathway

Signalling molecule binds to inactive receptor causing it to be come active this activate the Ras proteinRas protein activates kinase 1 converting ATP to ADP which activates kinase 2 so fourth down to kinase 3 Causing change in gene expression


What are the four essential elects for communication?

Signalling cellSignalling moleculeReceptor moleculeReceptor cell