CELL COMMUNICATION

YOU MUST KNOW… THE 3 STAGES OF CELL COMMUNICATION: RECEPTION, TRANSDUCTION, AND RESPONSE HOW G-PROTEIN-COUPLED RECEPTORS RECEIVE CELL SIGNALS AND START TRANSDUCTION HOW RECEPTOR TYROSINE KINASE RECEIVE CELL SIGNALS AND START TRANSDUCTION

YOU MUST KNOW… HOW A PHOSPHORYLATION CASCADE AMPLIFIES A CELL SIGNAL DURING TRANSDUCTION HOW A CELL RESPONSE IN THE NUCLEUS TURNS ON GENES WHILE IN THE CYTOPLASM IT ACTIVATES ENZYMES WHAT APOPTOSIS MEANS AND WHY IT IS IMPORTANT TO NORMAL FUNCTIONING OF MULTICELLULAR ORGANISMS

CONCEPT 11.1 EXTERNAL SIGNALS ARE CONVERTED INTO RESPONSES WITHIN THE CELL

3 STAGES FOR CELL SIGNALING RECEPTION – THE TARGET CELL’S DETECTION OF A SIGNAL MOLECULE COMING FROM OUTSIDE THE CELL TRANSDUCTION – THE CONVERSION OF THE SIGNAL TO A FORM THAT CAN BRING ABOUT A SPECIFIC CELLULAR RESPONSE RESPONSE – THE SPECIFIC CELLULAR RESPONSE TO THE SIGNAL MOLECULE

CONCEPT 11.2 RECEPTION: A SIGNAL MOLECULE BINDS TO A RECEPTOR PROTEIN, CAUSING IT TO CHANGE SHAPE

THE BINDING BETWEEN A SIGNAL MOLECULE (LIGAND) AND A RECEPTOR IS HIGHLY SPECIFIC RECEPTORS ARE FOUND IN 2 PLACES INTRACELLULAR RECEPTORS – INSIDE PLASMA MEMBRANE IN THE CYTOPLASM OR NUCLEUS. THE SIGNAL MOLECULE IS HYDROPHOBIC SO IT CAN CROSS THE MEMBRANE PLASMA MEMBRANE RECEPTORS – BIND TO WATER-SOLUBLE LIGANDS

G-PROTEIN-COUPLED RECEPTOR MEMBRANE RECEPTOR THAT WORKS WITH THE HELP OF A G-PROTEIN G-PROTEIN BINDS TO SIGNALING MOLECULE AND CAUSES A CHANGE IN THE RECEPTOR CAUSING THE INACTIVE G-PROTEIN TO BECOME ACTIVE G-PROTEIN ACTIVATES THE ENZYME MOLECULAR SHAPE CHANGES ARE TEMPORARY

RECEPTOR TYROSINE KINASE SIGNAL MOLECULES BIND TO THE RECEPTORS THAT FORMS A DIMER DIMER ADDS A PHOSPHATE FROM AN ATP MOLECULE THE ACTIVATED RECEPTOR PROTEIN INITIATES MULTIPLE CELLULAR RESPONSES FOR EACH PHOSPHORYLATED TYROSINE

LIGAND-GATED ION CHANNELS SPECIFIC SIGNAL MOLECULES CAUSE THE CHANNELS IN A MEMBRANE TO OPEN OR CLOSE, REGULATING THE FLOW OF SPECIFIC IONS

CONCEPT 11.3 TRANSDUCTION: CASCADES OF MOLECULAR INTERACTIONS RELAY SIGNALS FROM RECEPTORS TO TARGET MOLECULES IN THE CELL

PHOSPHORYLATION CASCADE A MULTISTEP PATHWAY THAT GREATLY AMPLIFIES THE SIGNAL ENZYMES CALLED PROTEIN KINASES PHOSHORYLATE AND ACTIVATE MANY PROTEIN AT THE NEXT LEVEL ALLOWS FOR A LARGE CELLULAR RESPONSE

SECOND MESSENGERS SMALL, NONPROTEIN WATER- SOLUBLE MOLECULES OR IONS ONCE ACTIVATED, THEY CAN INITIATE A PHOSPHORYLATION CASCADE RESULTING IN A CELLULAR RESPONSE EX. CALCIUM ION AND CYCLIC AMP

CONCEPT 11.4 RESPONSE: CELL SIGNALING LEADS TO REGULATION OF TRANSCRIPTION OR CYTOPLASMIC ACTIVITIES

PURPOSE OF SIGNALING PATHWAYS REGULATE PROTEIN SYNTHESIS, USUALLY BY TURNING SPECIFIC GENES ON OR OFF IN THE NUCLEUS OFTEN ACTS AS A TRANSCRIPTION FACTOR

CONCEPT 11.5 APOPTOSIS INTEGRATES MULTIPLE CELL SIGNALING PATHWAYS

APOPTOSIS PROGRAMMED CELL DEATH CELL IS SYSTEMICALLY DISMANTLED AND DIGESTED TRIGGERED BY SIGNALS THAT ACTIVATE A CASCADE OF “SUICIDE” PROTEINS IN THE CELLS