Which explanation identifies correctly how the G protein-linked receptors are similar? O Insulin is an example of the second messenger cyclic AMP (CAMP), which binds to an enzyme-linked receptor.
O Their cytosolic domain has intrinsic enzyme activity.
They have a ligand-binding extracellular receptor component, which causes changes that activate the protein on the cytoplasmic
side of the cell membrane.
These linked receptors are involved in rapid synaptic signaling between cardiac electrical cells.

Choose the incorrect statement (a) the motor end plate membrane is only capable of generating graded potentials, but it is contiguous with the skeletal muscle sarcolemma, which can generate action potentials. (b) propagation of an action potential through the t-tubules into the sarcoplasmic reticulum triggers the release of ca++ into the cytoplasm of a skeletal muscle fiber. (c) the generation of suprathreshold endplate potentials in multiple muscle fibers could be due to the increased frequency of action potential generation at the axon hillock of a single motor neuron. (d) a greater amount of ach would be found in the presynaptic vesicles of a motor unit that fired several action potentials after exposure to botulinum toxin, than in a motor unit that fired several action potentials after exposure to the venom of the krait snake (which contains α-bungarotoxin).