Quasar

one of a number of star-like heavenly bodies which are very distant from Earth and which give out light. They are extremely compact and give out light even though they are vast distances away, up to 10¹⁰ light years.

Taken from Dictionary of Science

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A quasi-stellar radio source (quasar) is a very energetic and distant galaxy with an active galactic nucleus. Quasars were first identified as being high redshift sources of electromagnetic energy, including radio waves and visible light, that were point-like, similar to stars, rather than extended sources similar to galaxies.

While there was initially some controversy over the nature of these objects—as recently as the early 1980s, there was no clear consensus as to their nature—there is now a scientific consensus that a quasar is a compact region in the centre of a massive galaxy surrounding the central supermassive black hole. Its size is 10-10,000 times the Schwarzschild radius of the black hole. The quasar is powered by an accretion disc around the black hole.

Taken from Wikipedia

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

Valency

is the bonding potential or combining power of an atom or group, measured by the number of hydrogen ions (H⁺, or equivalent) that the atoms could combine with or replace. In an ionic compound, the charge on each ion represents the valency, e.g., in NaCl, both Na⁺ and Cl^- have a valency of one. In covalent compounds, the valency is represented by the number of bonds formed. In carbon dioxide, CO₂, carbon has a valency of 4 and oxygen 2.

The electronic theory of valency explains bonds through the assumption that specific arrangements of outer electrons in atoms (outer shells of eight electrons) give stability (as with the inert gases, which have such a structure) through the transfer or sharing of electrons. Thus with the combination of sodium with chlorine, sodium has one electron in the outer shell, which it loses to chlorine to form the stable structure of the inert gas neon. Similarly, the gain of one electron by chlorine gives it the stable structure of argon.

Taken from Dictionary of Science

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In chemistry, valence, also known as valency or valency number, is a measure of the number of chemical bonds formed by the atoms of a given element. Over the last century, the concept of valence evolved into a range of approaches for describing the chemical bond, including Lewis structures (1916), valence bond theory (1927), molecular orbitals (1928), valence shell electron pair repulsion theory (1958) and all the advanced methods of quantum chemistry.

Taken from Wikipedia

Bacteriophage or Phage

a virus that attacks and infects a BACTERIUM.

Taken from Dictionary of Science

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A bacteriophage (from 'bacteria' and Greek φᾰγεῖν phagein "to eat") is any one of a number of viruses that infect bacteria. Bacteriophages are among the most common organisms on Earth. The term is commonly used in its shortened form, phage.

Typically, bacteriophages consist of an outer protein capsid enclosing genetic material. The genetic material can be ssRNA, dsRNA, ssDNA, or dsDNA ('ss-' or 'ds-' prefix denotes single-strand or double-strand) long with either circular or linear arrangement. Bacteriophages are much smaller than the bacteria they destroy.

Phages are estimated to be the most widely distributed and diverse entities in the biosphere. Phages are ubiquitous and can be found in all reservoirs populated by bacterial hosts, such as soil or the intestines of animals. One of the densest natural sources for phages and other viruses is sea water, where up to 9×10⁸ virions per milliliter have been found in microbial mats at the surface, and up to 70% of marine bacteria may be infected by phages. They have been used for over 60 years as an alternative to antibiotics in the former Soviet Union and Eastern Europe. They are seen as a possible therapy against multi drug resistant strains of many bacteria.

Taken from Wikipedia

Qualitative Analysis

the chemical examination of a sample to discover what substances are present.

Taken from Dictionary of Science

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In the qualitative analysis procedure, the chemical properties of an unknown substance are determined by systematically reacting the unknown with a number of different reagents. By predetermining what the particular reaction will produce if a specific ion is present, the ions that actually are in the solution can be identified. For example, if a reaction is known to produce a precipitate if ion A is present and a precipitate is formed when the reaction is run, then ion A may be present in solution (there may be, and usually are, other ions that will also precipitate with a particular reagent). If no precipitate is formed when the reaction is run, then ion A is clearly not present in the unknown solution and a different reaction will have to be run to determine what ions are present.

There are two general situations in which qualitative analysis is used - in the identification of a simple salt, or the identification of multiple cations in a solution.

Taken from Wired Chemist

Habit

the term for the characteristic external shapes of crystals due to the number, shape, size , and orientation of the crystal faces. The extent to which perfect habit may be approached depends upon conditions during formation, speed of growth, impurities etc. Individual crystals of particular minerals may show typical growths. Habits include tabular (flat blades), fibrous ( like thin fibres), prismatic (elongated) and acicular (needle-shaped).

Taken from Dictionary of Science

Factor

one of two or more quantities that produce a given quantity when multiplied together. For example, the factors of the number 8 are 1, 2, 4, 8.

Taken from Dictionary of Science

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Factors are the numbers you multiply together to get another number:

Example: 3 and 4 are factors of 12, because 3x4=12.

Also 2x6=12 so 2 and 6 are also factors of 12, and 1x12=12 so 1 and 12 are factors of 12 as well.

So ALL the possible factors of 12 are 1,2,3,4,6 and 12.

Taken from Math Is Fun?