BIOD 101 Module 5 Exam

Which of the following signaling types occurs during periods of development specifically for the secretion of growth factors? paracrine signaling Explain why a steroid hormone would require a carrier protein to transport it through the bloodstream. Steroid hormones are hydrophobic so they would need a carrier protein to carry it through the blood because carriers are hydrophilic Explain what a ligand is and give an example of one. A ligand is a molecule that has specificity for a given receptor and the binding to the receptor causes a change examples: hormones, peptides, sugars, and small hydrophobic molecules. What are the 3 steps involved in cellular communication, specifically when a cell receives an incoming message? reception, transduction, and response Which are the 3 types of cell surface receptors discussed in the module? G protein-coupled receptors (GPCRs), receptor tyrosine kinases (RTKs), and ligand-gated ion channels. What nucleotide does a G protein bind to? What is the broad role of all G proteins? G protein binds to nucleotide guanosine triphosphate (GTP), and the broad role is hydrolyzing GTP to GDP (guanosine diphosphate) What type of enzymes is an RTK, and what is the broad function of that enzyme? RTK is a kinase. Kinases transfer phosphate groups to a protein or another target molecule from an ATP molecule Describe what happens when a ligand binds to the extracellular binding site of a ligand-gated ion channel. A conformational change occurs, which causes the channel to open and allow the passage of ions such as calcium or chloride.