Zy

Zygote
A single living cell that results when a female egg is fertilized by sperm.
Zymase
Enzymes present in yeast that catalyze fermentation of sugar into alcohol and carbon dioxide.
Zymogen
An inactive precursor of an enzyme.
Zymoscope
An apparatus used for determining the fermenting power of yeast by measuring the amount of carbonic acid produced from a given quantity of sugar.