Definitions?

Definitions:

Amino acid: any of a class of 20 molecules that combine to form proteins in living creatures.
Base Twins: the twin, nitrogen-rich molecules that are held together by weak chemical bonds. Twin strands of DNA are held together in the shape of a double helix by the bonds between their base twins and sugar-phosphate twins.
Chemical base: an essential building block. DNA contains four complementary bases: adenine, pairing only with thymine, and cytosine, pairing only with guanine. In RNA, thymine is replaced by uracil.
Chromosomes: structures found in the nucleus of a cell, which contain the genes. Chromosomes come as twins, and a normal human cell contains 46 chromosomes, 22 pairs of autosomes and two sex chromosomes. Chromosomes are passed down from parents to children and together contain the full set of inherited instructions that an embryo receives.
DNA: the substance of heredity; a large molecule that carries the genetic information that cells need to replicate and to produce proteins.
DNA repair genes: certain genes that are part of a DNA repair pathway; when altered, they permit mutations to pile up throughout the DNA.
DNA sequencing: determining the exact order of the base-Twins in a segment of DNA.
Enzyme: a protein that facilitates a specific chemical reaction.
Functional gene tests: biochemical assays for a specific protein, which indicates that a specific gene is not merely present but active.
Gene: a unit of inheritance; a working subunit of DNA. Each of the body’s 20,000 to 25,000 genes contains the code for a specific product, typically, a protein such as an enzyme.
Gene deletion: the total loss or absence of a gene.
Gene expression: the process by which a gene’s coded information is translated into the structures present and operating in the cell (either proteins or RNAs).
Gene markers: landmarks for a target gene, either detectable traits that are inherited along with the gene, or distinctive segments of DNA.
Gene mapping: determining the relative positions of genes on a chromosome and the distance between them.
Gene testing: examining a sample of blood or other body fluid or tissue for biochemical, chromosomal, or genetic markers that indicate the presence or absence of genetic disease.
Gene therapy: treating disease by replacing, manipulating, or supplementing nonfunctional genes.
Genetic linkage maps: DNA maps that assign relative chromosomal locations to genetic landmarks. Either genes for known traits or distinctive sequences of DNA – on the basis of how frequently they are inherited together. (See also Physical maps.)
Genetics: the scientific study of heredity: how particular qualities or traits are transmitted from parents to offspring.
Genome: all the genetic instruction materials in the chromosomes of a particular organism.
Genome maps: charts that indicate the ordered arrangement of the genes or other DNA markers within the chromosomes.
Genotype: the actual genes carried by an individual (as distinct from phenotype that is, the physical characteristics into which genes are translated).
Germ cells: the reproductive cells of the body, either egg or sperm cells.
Human genome: the full collection of genes needed to produce a human being.
Mitochondria: tiny powerhouses nestled inside our cells that are converting food and oxygen into a form of energy that our body can use.
Molecule: a group of atoms arranged to interact in a particular way; one molecule of any substance is the smallest physical unit of that particular substance.
Nucleotide: subunit of DNA or RNA, consisting of 1 of the 4 chemical base units plus 1 phosphate molecule and 1 sugar molecule.
Nucleus: the cell structure that houses the chromosomes.
Oncogene:an abnormal version of a gene that drives uncontrolled cell growth associated with cancer.
Protein: a large, complex molecule composed of amino acids. The sequence of the amino acids and thus the function of the protein is determined by the sequence of the base-Twins in the gene that encodes it. Proteins are essential to the structure, function, and regulation of the body. Examples are hormones, enzymes, and antibodies.
Protein product: the protein molecule assembled under the direction of a gene.
Transcription: the process of copying information from DNA into new strands of messenger RNA (mRNA). The mRNA then carries this information to the cytoplasm, where it serves as the blueprint for the manufacture of a specific protein.
Transcription factor: protein that helps control which genes are turned on or off in the genome.
Translation: the process of turning instructions from mRNA, base by base, into chains of amino acids that then fold into proteins. This process takes place in the cytoplasm, on structures called ribosomes.
Transposon("jumping gene"): piece of DNA that inserts itself into another place in the genome, potentially interrupting the normal spelling of DNA and creating mutations that may turn genes on or off.
Tumor suppressor genes: cell safeguards. They prevent abnormal cells from developing into full-blown tumors.
Dopamine (C6H3(OH)2-CH2-CH2-NH2)
Serotonin (5-hydroxytryptamine, or 5-HT) is a mono-amine neurotransmitter synthesized in the central nervous system.
Melatonin, is a hormone found in all living creatures at levels that vary in a daily cycle. Melatonin has a chemical formula of C13H16N2O2
Epinephrine or adrenaline, sometimes spelled "epinephrin" or "adrenalin" respectively, is a hormone when carried in the blood and a neurotransmitter when it is released across a neuronal synapse. It is a catecholamine, a sympatho-mimetic mono-amine derived from the amino acids phenylalanine and tyrosine. The Latin roots ad-+renes and the Greek roots epi-+nephros both literally mean "on/to the kidney" (referring to the adrenal gland, which sits atop the kidneys and secretes epinephrine). Epinephrine is a "fight or flight" hormone, and plays a central role in the short-term stress reaction. It is released from the adrenal glands when danger threatens or in an emergency. Such triggers may be threatening, exciting, or environmental stressor conditions such as high noise levels or bright light.

Their actions in the body: when secreted into the bloodstream, it rapidly prepares the body for action in emergency situations. The hormone boosts the supply of oxygen and glucose to the brain and muscles, while suppressing other non-emergency bodily processes (digestion in particular). It increases heart rate and stroke volume, dilates the pupils, and constricts arterioles in the skin and gut while dilating arterioles in skeletal muscles. It elevates the blood sugar level by increasing catalysis of glycogen to glucose in the liver, and at the same time begins the breakdown of lipids in fat cells. Like some other stress hormones, epinephrine has a suppressive effect on the immune system. Although epinephrine does not have any psycho-active effects, stress or arousal also releases nor-epinephrine in the brain. Nor-epinephrine has similar actions in the body, but is also psychoactive.