In the nervous system, a synapse is a structure that permits a neuron to pass an electrical or chemical signal to another cell (neural or otherwise).
There are two fundamentally different types of synapses:
Longevity escape velocity: the point at which life-extending technologies improve at a fast enough rate to allow new life-extension technologies to be developed before death. If we achieve this as a species, we (or at least some of us) can become effectively “functionally immortal” (mmm, immortality) – we won’t have to die from disease or debilitation, although we can always fall prey to accident or foul-play.
The unique collection of connected neurons that makes up a particular brain; or a system that models or emulates this, in order to attempt to create artificial intelligence. The difference between neurons and, say, network nodes is that neurons are highly connected and “not digital” – they may or may not fire based on the excitation energy from the connected neurons and “ephatic coupling” (see synapse).
An important molecule in biochemistry: proteins are linear chains of amino acids, with various sequences of amino acids forming a variety of proteins. The 22 amino acids naturally incorporated into polypetides are called “standard” or proteinogenic, whilst 9 are labelled “essential” as they cannot be produced by the human body.