Bio chapter 11 Cell communication

Which of the following statements is true of signal molecules?
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Phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because they ________.amplify the original signal many timesLipid-soluble signaling molecules, such as aldosterone, cross the membranes of all cells but affect only target cells becauseintracellular receptors are present only in target cells.What role do phosphatases play in signal transduction pathways?They inactivate protein kinases to turn off signal transduction.Hormones are chemical substances produced in one organ that are released into the bloodstream and affect the function of a target organ. Which of the following conditions is required for the target organ to respond to a particular hormone?The target organ must have receptors that recognize and bind the hormone molecule.The receptors for steroid hormones are located inside the cell instead of the membrane surface like most other signal receptors. How do steroids gain access to their receptors?Steroid hormones are lipid soluble, so they can readily diffuse through the lipid bilayer of the cell membrane.In the figure, the dots in the space between the two structures represent which of the following?neurotransmittersWhich of the following is a type of local signaling in which a cell secretes a signal molecule that affects neighboring cells?paracrine signalingPut the steps of the process of signal transduction in the order they occur. 1. A conformational change in the signal-receptor complex activates an enzyme. 2. Protein kinases are activated. 3. A signal molecule binds to a receptor. 4. Target proteins are phosphorylated. 5. Second messenger molecules are released.3, 1, 5, 2, 4Which of the following statements describes the events of apoptosis?The cell's DNA and organelles become fragmented, the cell shrinks and forms blebs, and the cell's parts are packaged in vesicles that are digested by specialized cells.Protein kinase is an enzyme that functions in which of the following ways?activates or inactivates other proteins by adding a phosphate group to them