AP BIOLOGY

Detailed explanation-1: -Answer and Explanation: Binding of a signal molecule to an ligand gated ion channel will lead to the change in the distribution of ions when opposite sides of a membrane.

Detailed explanation-2: -Signaling molecules bind to the extracellular domain of two nearby tyrosine kinase receptors, which then dimerize. Phosphates are then added to tyrosine residues on the intracellular domain of the receptors and can then transmit the signal to the next messenger within the cytoplasm.

Detailed explanation-3: -2. Transduction: When the signaling molecule binds the receptor it changes the receptor protein in some way. This change initiates the process of transduction. Signal transduction is usually a pathway of several steps.

Detailed explanation-4: -The release of neurotransmitters is signaled by the arrival of an action potential at the terminus of a neuron (see Figure 12.22). The neurotransmitters then diffuse across the synaptic cleft and bind to receptors on the target cell surface. Note that some neurotransmitters can also act as hormones.

Detailed explanation-5: -Gated ion channels form a pore through the plasma membrane that opens when the signaling molecule binds. The open pore then allows ions to flow into or out of the cell. Ion channel-linked receptors bind a ligand and open a channel through the membrane that allows specific ions to pass through.