The atmosphere is quite dusty, giving the Martian sky a light brown or orange-red color when seen from the surface; data from the Mars Exploration Rovers indicate that suspended dust particles of roughly 1.5 micrometres diameter.
Glutamate is a powerful excitatory neurotransmitter that is released by nerve cells in the brain. It is responsible for sending signals between nerve cells, and under normal conditions it plays an important role in learning and memory.
In biochemistry, the glutamate-glutamine cycle is a sequence of events by which an adequate supply of the neurotransmitter glutamate is maintained in the central nervous system. Neurons are not able to perform new synthesis of the neurotransmitter glutamate and y-aminobutyric acid (GABA) from glucose.