Y-Chromosome. The sex-chromosome found only in the heterogametic sex. Usually differs from the X-Chromosome in size. Often only a short part of it pairs with the X-chromosome at meiosis, and it usually contains few or no major genes.
Yeasts. Widely distributed unicellular fungi, belonging mainly to the Ascomycetes, which multiply typically by a budding process. Of great economic importance. The brewing and baking industries depend upon capacity of yeasts to secrete enzymes that convert sugars into alcohol and carbon dioxide.
In the former industry alcohol is the important product, in the latter escaping carbon dioxide causes dough to rise. Yeasts are also used commercially as a source of proteins and vitamins
Y-linked. One which can only be transmitted through the hemizygous sex, i.e. males in mammals.
Yolk. The food material scored in form of protein and fat granules, in eggs of majority of animals.
