Select Page

Archives: Dictionary

Y chromosome

(Science: genetics) The small chromosome that is male-determining in most mammal species and found only in the heterogametic sex. Thus in mammals the male has one y chromosome and one x chromosome. One region of the y chromosome, the pseudoautosomal region, is homologous to and pairs with the X chromosome. The primary determinant of male sexual development is found on the unpaired, differentiated segment of the y chromosome. It carries few other genes besides those dictating sperm development and triggering appropriate hormonal output. The sex chromosome that is carried by men; human males normally have one x chromosome and one Y chromosome.One of the sex chromosomes that has the genetic information to produce male offspring, that is accompanied by chromosome X. Some inherited characteristics in offspring (such as hairy ears and colour blindness in men) are believed to be sex linked, I.e. in....

Read More


/ˈjɪəlɪŋ,ˈjəː-/ Noun 1. An animal (especially a sheep, calf, or foal) that is a year old or that is in its second year (Google Dictionary); An animal that is between one and two years old ( 2. A racehorse that is considered to be one year old until a subsequent January 1st ( Adjective 1. Having lived for a year; a year old. (Google...

Read More


/yēst/  Noun, pl. yeasts 1. A microscopic fungus consisting of single oval cells that reproduce by budding, and are capable of converting sugar into alcohol and carbon dioxide. (Google Dictionary) 2. A grayish-yellow preparation of this obtained chiefly from fermented beer, used as a fermenting agent, to raise bread dough, and as a food supplement. (Google Dictionary) 3. Any unicellular fungus that reproduces vegetatively by budding or fission, including forms such as candida that can cause disease. (Google Dictionary) 4. These are eukaryotic microorganisms classified in the kingdom Fungi, with 1,500 species currently described (estimated to be 1% of all fungal species). Yeasts are unicellular, although some species with yeast forms may become multicellular through the formation of a string of connected budding cells known as pseudohyphae, or false hyphae, as seen in most molds. ( 5. An often humid, yellowish froth produced by fermenting malt worts, and used to brew beer, leaven bread, and also used in certain medicines. ( 6. A type of single-celled fungus....

Read More


/jəʊk/ Noun, plural yolks 1. Material stored in an ovum that supplies food to the developing embryo and consists chiefly of proteins, lecithin, and cholesterol. ( 2. The yellow internal part of a bird’s egg, which is surrounded by the white, is rich in protein and fat, and nourishes the developing embryo (Google Dictionary); The yellow, spherical part of an egg that is surrounded by the white albumen, and serves as nutriment for the growing young. ( 3. Also called Deutoplasm, the nutritive material of an egg, used as food by a developing, embryonic animal. ( 4. A corresponding portion of the egg of other animals, consisting of protein and fat that serve as the primary source of nourishment for the early embryo and protoplasmic substances from which the embryo develops. ( 5. The grease in a sheep’s fleece. ( Word origin: Old English geolca, geoloca “yolk,” literally “the yellow part,” from geolu...

Read More

Struggling in Biology?

Are You Premed?

Confused about the MCAT? Not sure how to prepare? This guide will show you how