Biology Y
What is Y chromosome ?
The nuclei of human cells contain 22 autosomes (any chromosome that is not a sex chromosome) and two sex chromosomes. In females, the sex chromosomes are the two X chromosomes, and in males there is one X chromosome and one Y chromosome. The presence of the Y chromosome leads to a baby boy.
What is yeast ?
Considered to be the oldest “plant” cultivated by humans. Yeast is a unicellular fungus that belongs to the family Saccharomycetaceae. It lives in the soil, on plants, and is airborne, and it has been used in the production of bread, beer, and wine because it drives the process of fermentation. It produces carbon dioxide and alcohol when in the presence of sugar.
What is yellow fever ?
A tropical mosquito-borne viral hepatitis caused by an arbovirus (yellow fever virus) from the Flaviviridae family. It is transmitted by the mosquitoes Aedes aegypti and Haemagogus capricorni, among others.
What is yolk sac ?
An extraembryonic tissue (membranous sac) that is attached to an embryo and contains the nutritive food yolk. In fish larvae, the alevin-stage embryos swim with the yolk sac attached until it is absorbed. In placental mammals, it is vestigial (contains no nutrients). The primitive yolk sac divides into two parts: one portion becomes the fetal gastrointestinal tract, while the second portion connects to the fetal body via the vitelline duct and is located in the fluid space outside the amnion, the extraembryonic coelom. It produces the embryo’s first blood cells and germ cells that develop into gonads; is the source of the mucous membrane of almost the entire intestinal tract; and deals with the transfer of nutritive fluid to the embryo from the trophoblast, primary mesenchyme, and extraembryonic coelom.
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