Final answer:
Neurotransmitters are chemicals that diffuse across the synaptic cleft and are not usually attached to the cell surface; they bind to postsynaptic receptors to transmit signals. The incorrect statement is that neurotransmitters, like Delta or Notch, are usually attached to the cell surface. This is false, as they function by diffusing and not by remaining attached.
Step-by-step explanation:
The correct statement that is not true regarding a neurotransmitter is that 'Like Delta or Notch, neurotransmitters are usually attached to the cell surface'. This statement is incorrect because neurotransmitters are chemical messengers that diffuse across the synaptic cleft to transmit a signal from one neuron to the next, or to a muscle cell; they do not remain attached to the cell surface as do some proteins involved in cell signaling like Delta or Notch. Instead, neurotransmitters are released by presynaptic neurons and bind to receptors on the postsynaptic neuron. The characteristics of a synapse can vary based on the specific neurotransmitter involved, and neurotransmitters such as acetylcholine, dopamine, GABA, and glutamate have different effects depending on the receptors they activate on target cells.
Neurotransmitters aid in functions such as muscle contraction, but they are not growth factors although they can influence cellular functions including growth under certain conditions. The accurate statements about neurotransmitters are that they are produced by neurons, operate over short distances, and influence muscle contraction, but they are not usually attached to the cell surface.