The cellular process in which a signal is conveyed to trigger a change in the activity or state of a cell. Signal transduction begins with reception of a signal (e.g. a ligand binding to a receptor or receptor activation by a stimulus such as light), or for signal transduction in the absence of ligand, signal-withdrawal or the activity of a constitutively active receptor. Signal transduction ends with regulation of a downstream cellular process, e.g. regulation of transcription or regulation of a metabolic process. Signal transduction covers signaling from receptors located on the surface of the cell and signaling via molecules located within the cell. For signaling between cells, signal transduction is restricted to events at and within the receiving cell.

The series of events required for an organism to receive a visual stimulus, convert it to a molecular signal, and recognize and characterize the signal. Visual stimuli are detected in the form of photons and are processed to form an image.

The series of events required for an organism to receive a visual stimulus, convert it to a molecular signal, and recognize and characterize the signal. Visual stimuli are detected in the form of photons and are processed to form an image.

The sequence of reactions within a cell required to convert absorbed photons into a molecular signal.

The process in which the structures of a photoreceptor cell are generated and organized. This process occurs while the initially relatively unspecialized cell is acquiring the specialized features of a photoreceptor cell, a sensory cell that reacts to the presence of light. An example of this is found in Drosophila melanogaster.

Development of a cone cell, one of the sensory cells in the eye that reacts to the presence of light. Cone cells contain the photopigment iodopsin or cyanopsin and are responsible for photopic (daylight) vision.

The process in which a relatively unspecialized cell acquires specialized features of a bipolar cell, the last neuron to be generated in the retina.

The space external to the outermost structure of a cell. For cells without external protective or external encapsulating structures this refers to space outside of the plasma membrane. This term covers the host cell environment outside an intracellular parasite.

The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes.

The part of the cytoplasm that does not contain organelles but which does contain other particulate matter, such as protein complexes.

Terminal inflated portion of the axon, containing the specialized apparatus necessary to release neurotransmitters. The axon terminus is considered to be the whole region of thickening and the terminal bouton is a specialized region of it.

The junction between a nerve fiber of one neuron and another neuron, muscle fiber or glial cell. As the nerve fiber approaches the synapse it enlarges into a specialized structure, the presynaptic nerve ending, which contains mitochondria and synaptic vesicles. At the tip of the nerve ending is the presynaptic membrane; facing it, and separated from it by a minute cleft (the synaptic cleft) is a specialized area of membrane on the receiving cell, known as the postsynaptic membrane. In response to the arrival of nerve impulses, the presynaptic nerve ending secretes molecules of neurotransmitters into the synaptic cleft. These diffuse across the cleft and transmit the signal to the postsynaptic membrane.