Apoptosis is the programmed death of cells. It is a mechanism of the organism to maintain a relative constant and normal number of cells. It also includes a cascade of biological processes that result to the death of a cell, when it is seriously damaged or infected by a virus.

Adipocyte is the main type of cells that compose adipose tissue and are also known as fat cells, or lipocytes. Their main function is to store energy in the form of fat.

Allele is one member of the pair that makes up a gene. Genes come in pairs and each allele is an alternative form of the gene.

Amino acids are components of proteins. Some are synthesized by the body (nonessential amino acids) and others must be obtained through diet (essential amino acids).

Antioxidant is a substance that can protect the cells from damages caused by conditions of oxidative stress.

β (beta)-pancreatic cells are a type of cells in pancreas which are responsible for the production and secretion of insulin.

BMD (Bone Mineral Density) is a measure of bone density. BMD test is used to define loss of bone mass and detect osteoporosis.

BMI (Body Mass Index) is a statistical measurement, used to estimate whether individuals have normal body weight. It compares weight and height based on the mathematic formula: BMI= mass (kg)/ height2(m2)

Carcinogen is an agent (substance or radiation) that is involved in the development of cancer. Carcinogens can cause serious damage either to the DNA or the metabolic functions of cells.

Detoxification is the process of removing or inactivating toxic substances from the body. It is crucial for cells to maintain their ability to detoxify themselves from substances, which have the potential to cause serious damages.

DNA is a large molecule found in the nucleus of the cell. It contains the essential genetic information for the function of living organisms and has a significant role in the development of all traits that define our individuality. Its molecular structure in place has the shape of a double spiral, called double helix.

DNA sequence is a succession of nucleotides in the DNA molecule.

DNA testing utilizes techniques that enable scientists to define the DNA sequence or detect certain nucleotides at specific positions of the DNA.

Carbohydrate is a compound of carbon, hydrogen and oxygen. It is an important source of energy found in food.

Cell is the smallest functioning unit in the structure of an organism. It is enclosed by a membrane and contains a nucleus and organelles with certain functions (mitochondria, lysosomes, ribosomes).

Cell cycle is the series of events that result to cell division and cell proliferation. A process very important for development, growth, wound healing.

Cholesterol is a waxy, fat-like substance essential for the structure of cell membrane. It is also a component of certain hormones and some Vitamins and is transported with lipoproteins through blood circulation.

Chromosome is a rod-shaped compound of DNA and proteins found in a cell nucleus. The structure serves the DNA package in the nucleus and the control of DNA functions. A human body cell normally contains 46 chromosomes arranged in 23 pairs.

Chromatin is the combination of DNA and proteins which when condensed makes up chromosomes.

Enzyme is a protein that controls biochemical reactions, resulting to either production or inactivation of substances in cells.

Genes represent small segments of the DNA molecule which are the structural units of heredity in all living organisms. They contain the genetic information which can be used by cells. The human genome contains approximately 30,000 genes, which are located at specific positions on chromosomes.

Genetic profile results from analysis of several genes in the DNA of an individual. It can be informative for the genetic tendencies of individuals regarding the trait under consideration.

Genotype describes the constitution of gene (the type of the gene). It refers each time to a specific gene under investigation, describing the alleles that the gene contains. It often refers to the pair of the nucleotides found at a specific position of the DNA sequence.

Genome is the total genetic material of a cell. It is the full complement of genetic information that an organism inherits from parents.

Glucose is a very important carbohydrate in biological systems. It is used by cells as a source of energy and is also an intermediate of metabolism.

HDL (High Density Lipoprotein) transports lipids through blood circulation. Due to its ability to remove cholesterol from arteries to liver and prevent serious damages, it is also called "good cholesterol".

Homeostasis is a state of equilibrium (balance) or the tendency to reach equilibrium. It is the ability of a living organism to regulate its internal environment in order to maintain a stable condition.

Homocysteine is an amino acid, important for the production of another amino acid called Cysteine. Homocysteine metabolism and maintenance of normal levels is crucial for the health, as elevated homocysteine levels in blood associate primarily with problems of the cardiovascular system.

HR max (Heart Rate max) is the maximal number of heartbeats per unit of time. It should be estimated by specialized medical staff before an individual begins an exercise training program.

HR reserve (Heart Rate reserve) describes the difference between a person's HR max and resting Heart rate (heart beats during resting). It is used in some cases of measuring the intensity of physical exercise.

Immune response is the response of the immune system: the mechanism activated to defend against foreign harmful substances that come into the body, pathogens, and tumor cells.

Inflammation is a process by which the body activates certain types of cells to protect us from infections and substances recognized as foreign.

Insulin is a hormone produced in pancreas. It causes cells of fat tissue, liver and muscle to take up glucose from blood and use it as energy source.

LDL (Low Density Lipoprotein) transports lipids through blood circulation. LDL is often called "bad cholesterol" as elevated LDL levels are harmful for the cardiovascular system.

Lipid is a molecule naturally produced in the body with the main role of energy storage. Certain types of lipids are obtainedthrough diet from fats contained in food. With lipid metabolism, the body synthesizes or degrades the fats to produce lipids with the essential characteristics. Triglycerides and fatty acids belong to lipids.

Lipoprotein is a compound of lipid and protein which transport lipids (fats) and cholesterol around the body through blood circulation. HDL, LDL, and VLDL belong to lipoproteins.

Metabolism is a group of chemical reactions that take place in a living organism to maintain life, develop and reproduce. It includes the processes of constructing components of cells (anabolism) and breaking down compounds (catabolism) to produce energy.

Molecule is the smallest part of a chemical compound which can exist independently. It consists of one or more atoms held together by chemical forces.

Mutagen is an agent which can cause a change in the genetic material of an organism.

Mutation is a change in the genetic material of an organism. Regarding human cells, mutation refers to a change in the sequence of the DNA. Mutations are responsible to a significant degree for the variability of characteristics observed in the human population. Mutations can be beneficial, harmful or even neutral, having no effect. They result to different forms of alleles in genes, and are often called polymorphisms. The effect of mutations is often affected by environmental factors.

Nucleotides are the structural molecules of the genetic material. In DNA each nucleotide is represented by a letter, which can be A, T, C, or G, each defined by the base that the nucleotide contains (Adenine, Thymine, Cytosine, or Guanine). When they are joined together and based on their succession, nucleotides define certain genetic information.

Oxidative stress is caused in cells due to their reduced ability to fight against oxidative factors, which are substances like peroxides and free radicals. These can be either by-products of normal functions of cells or can be produced by environmental toxic substances when they enter the body. In both cases they can have toxic effects as they can damage seriously the components of cells (proteins, lipids, DNA).

Pharmacogenomics is the field of Pharmacology and Genetics, which investigates how the DNA of individuals affects their response to drugs. Based on DNA testing, it aims to identify which drugs have increased efficacy or cause reduced toxicity to an individual.

Predictive genomics is the field of Medicine which identifies mutations in the DNA of an individual in order to predict the likelihood of this individual to develop certain characteristics, abilities or conditions.

Proteins are molecules made of amino acids. They are essential parts of organisms and take part in energy metabolism.

Vitamin is a compound necessary for an organism to function properly. A compound is characterized as Vitamin, when it is essential to be provided by diet as it cannot be synthesized in adequate amounts by an organism.

VLDL (Very Low Density Lipoprotein) transport lipids through blood circulation.

VO2 max is the maximal oxygen consumption, describing the amount of oxygen transported and used during physical exercise of individuals. It is an important factor for the physical fitness.

Xenobiotic is a chemical which can be found in an organism but it is not normally produced by it nor obtained by diet. Drugs and antibiotics are examples of xenobiotics.