Question

Region	Function	Protein
Dendrite
Soma
Axon
Axon terminal

Complete the table above on the regions of the neuron, their primary function(s), and a specific protein that supports that function. Explain your choice of protein.

Answer 1

Region	Function	Protein
Dendrite	Dendrites are finger like extensions of the neurons that receive impulses or signals from other neurons/external environment and pass them to cell body/soma. The signals can be excitatory or inhibitory. Dendrites contain numerous synapses. At the synapse, the pre-synaptic neuron releases the neurotransmitter. This neurotransmitter bind to the receptors present on the dendrites of post-synaptic neuron. Some neurons have small protrusions called dendritic spines, which increase detection of neurotransmitters.	Dendritic synapses contain protein receptors that bind to neurotransmitters. Receptors are present for neurotransmitters such as dopamine, serotonin, norepinephrine, GABA and glutamate. These receptors can be ionotrophic (ligand gated ion channels) or metabotropic (G-coupled receptors). Ionotrophic glutamate receptors bind to neurotransmitter glutamate. The transmitter diffuses across the synaptic cleft. It can either stimulate or inhibit the next cell in by interacting with receptor proteins. The channels of these receptors will open only when glutamate is present. Once the channel opens, charged ions such as sodium or calcium will enter through, causing depolarization. As a result, the signal is passed to the cell body.
Soma	Soma or cell body is the spherical part of neuron that harbor the nucleus. It connects the dendrite to the axon. The cell body receives signal from the dendrites and passes it to the axon. The nucleus is responsible for regulating all processes in the cell body. Cell body contains ribosomes, endoplasmic reticulum and the Golgi, that helps to synthesize and package proteins to different parts of neuron. These proteins will form new axons and dendrites and help transmit signals. The mitochondria will provide energy to neuron. Microtubules are involved in transmission of signals	Beta tubulin is present in the cell body. It is a part of the microtubules and binds to other cytoskeletal filaments. Tubulins provide stability to the cell body and also help transmit signals to the axons.
Axon	Axons carry signals away from the cell body and conduct nerve impulses. Axons split into several branches to send impulses to different neurons. Axon contains a myelin sheath around it, present as concentric circles. Myelin sheath protects the axon and is involved in signal transmission. Schwann cells (PNS) synthesize myelin and are wrapped around the axon. In CNS, Oligodendrocytes are present, instead of Schwann cells.	V-gates ions channels, passive on channels and Na-K pump is present in the axons. V-gated ion channels transmit sodium and potassium in axons of neurons. Integral proteins are associated with these channels. They have an alpha subunit that is associated with auxillary beta subunits. Potassium channel has an alpha subunit that is organized in four domains with six transmembrane segments. Tau protein is associated with axon. It is involved in microtubule stabilization an assembly by binding to it. Increase phosphorylation is involved in formation of neurofibrils in Alzheimers disease. This results in neurodegeneration.
Axon terminal	Axon terminals are sites of neurotransmitter release. They release the neurotransmitter acetylcholine. Acetylcholine is a neurotransmitter that is causes muscle contraction.	Acetylcholine is a protein neurotransmitter that is released by axon terminal at synaptic cleft in response to an electrical impulse. It binds to the receptors on the synaptic cleft and causes release of calcium ions. Calcium then causes the interaction between actin and myosin to allow muscle contraction.