Karyotype

the number, shapes and sizes of the chromosomes within the cells of an organism. Every organism has a karyotype that is characteristic of its own species, but different species have very different karyotypes. For example, all normal human females have 22 pairs of DIPLOID chromosomes with a similar shape and size, but all female horses have 32 pairs of diploid chromosomes which have their own unique shape and size.

Taken from Dictionary of Science

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A karyotype is the characteristic chromosome complement of a eukaryote species. The term may also be used of a cell, or an individual. The preparation and study of karyotypes is part of cytogenetics.

The basic number of chromosomes in the somatic cells of an individual or a species is called the somatic number and is designated 2n. Thus, in humans 2n = 46. In the germ-line (the sex cells) the chromosome number is n (humans: n = 23).

So, in normal diploid organisms, autosomal chromosomes are present in two copies. There may, or may not, be sex chromosomes. Polyploid cells have multiple copies of chromosomes and haploid cells have single copies. The study of whole sets of chromosomes is sometimes known as karyology. The chromosomes are depicted (by rearranging a microphotograph) in a standard format known as a karyogram or idiogram: in pairs, ordered by size and position of centromere for chromosomes of the same size.

Karyotypes can be used for many purposes; such as, to study chromosomal aberrations, cellular function, taxonomic relationships, and to gather information about past evolutionary events.

Taken from Wikipedia

Vacuum Distillation

distillation performed under reduced pressure. Since a reduction in pressure also reduces the boiling point of substances it means that certain substances which at normal pressures would decompose (break down), can be distilled.

Taken from Dictionary of Science

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Vacuum distillation is a method of distillation whereby the pressure above the liquid mixture to be distilled is reduced to less than its vapor pressure (usually less than atmospheric pressure) causing evaporation of the most volatile liquid(s) (those with the lowest boiling points). This distillation method works on the principle that boiling occurs when the vapor pressure of a liquid exceeds the ambient pressure. Vacuum distillation is used with or without heating the solution.

Taken from Wikipedia

Y-chromosome

the small chromosome that carries a dominant gene for maleness. All normal males have 22 matched pairs of chromosomes and one unmatched pair, one large X-chromosome and one small Y-chromosome. The X-chromosome, which is inherited from the mother, carries many more genes than the Y-chromosome, which is inherited from the father. During sexual reproduction, the mother must contribute one X-chromosome, but the father can contribute either an X or Y-chromosome. The effect of the Y-chromosome is that a testis develops in the embryo instead of an ovary. Thus the sex of the resulting offspring is dependent on the father's contribution -- female (X,X) or male (X,Y).

Taken from Dictionary of Science

Calcium

a metallic substance with the symbol Ca which is common in nature being found in both plants and animals. It is essential for the normal growth and development of animals, being found in bones, teeth, blood and nerves.

Taken from Dictionary of Science

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Calcium (pronounced /ˈkælsiəm/, KAL-see-əm) is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth most abundant element by mass in the Earth's crust. Calcium is also the fifth most abundant dissolved ion in seawater by both molarity and mass, after sodium, chloride, magnesium, and sulfate.

Calcium is essential for living organisms, particularly in cell physiology, where movement of the calcium ion Ca²⁺ into and out of the cytoplasm functions as a signal for many cellular processes. As a major material used in mineralization of bones and shells, calcium is the most abundant metal by mass in many animals.

Taken from Wikipedia

When Words Appear Backwards

A dook si harb ot reab wheu you avea learmimg bisadlity.

This is what those with dyslexia might see when they attempt to read a normal sentence.

Known as the "invisible handicap" or "word blindness," dyslexia is a learning disorder that affects a person's ability to read letters or words.

Reading can become almost impossible because letters and words may appear backward, sideways or seem to float off the edge of a page. The letters most often confused are b, d, p and q. For example, dog may be seen as bog.

Dyslexics also have difficulty recognizing and remembering printed shapes. This often causes writing that is cramped and difficult to read.

Dyslexia occurs in boys three times as often as in girls and research reveals that it runs in families. Unnoticed at birth because there are no visible physical imperfections, dyslexia can affect as many as 10 percent of school-age children. What causes it is unknown and there seems to be no cure.

Dyslexia has nothing to do with intelligence--most who suffer from it are above average in intelligence. The frustration occurs with the dyslexic's inability to transfer thoughts correctly to paper.

Parents and teachers not understanding the problem may accuse dyslexics of not trying hard enough or being lazy. Many dyslexics in the past have been classified as slow or retarded.

What effect can this disability have on you as a teen? There is a good chance that someone you know is dyslexic.

If so, you can help by reading assignments aloud and helping correct his or her spelling mistakes. Most important of all, accept the person.

Dyslexia is not a disease, but a difference.

- By Lu Anne Girard Warren

Taken from Youth 90 magazine