If you enjoy murder mysteries,then you know there are many ways a villain can murder a victim.
Many of these methods, like shooting someone with a gun, are pretty straightforward. What might not be so obvious are workings of some of the more subtle weapons in a mystery writer's arsenal. For example, poisons. Let's take a look at a mystery writer's favorite, and learn how cyanide kills.
Cyanide works by interfering with the subtle chemical mechanism of our cells. In order to survive, our cells need energy, and they get this energy, in part, from the sugars in the foods we eat. In a chemical reaction known as "respiration," our cells use oxygen molecules from the air we breath to free up energy from sugar.
Cyanide molecules act like a monkey wrench in a cell's mechanism of respiration. Cyanide looks like oxygen to the parts of the cell responsible for respiration. In fact, if there are both oxygen molecules and cyanide molecules present in the bloodstream, our cells will grab onto the cyanide molecules first, and try to use these, instead of oxygen, to get energy out of sugar. However the cyanide won't work that way, and will only gum up the cell's energy delivery system. It's a little like trying to run a car on peanut butter instead of gasoline, the peanut butter only clogs the car's fuel system.
With its respiration mechanism gummed up, the cell will eventually die. If enough cells die, then the victim dies, and you've got the start of your next mystery novel.