The science of Twilight vampires (i.e. vampires in the Twilight universe) is based around "vampire venom." This venom is not merely an organic chemical substance, it is actually a fluid-based lifeform. It also behaves like a virus or, more specifically, a retrovirus. It will attach itself to a host cell, sometimes shrinking to the size of a virus or most likely dividing itself into many virus sized molecular structures and attaching themselves to the host cell's membrane. The venom-virus then infects the host cell, making a DNA copy of the genome for use in making RNA. This RNA could be used as a template for making more viral genomes and as mRNA to produce viral proteins, which is known as reverse transcription. Venom cells grown in size and seem to attack white blood cells first. The hos