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An egg (in the female) or sperm (in the male) cell.

The process by which a blastula becomes a gastrula or, in forms without a true blastula, the process by which three germ cell layers are acquired. In humans, the conversion of a bilaminar to a trilaminar embryonic disc (ectoderm, mesoderm, endoderm).

A functional unit of heredity that is a segment of DNA found on chromosomes in the nucleus of a cell. Genes direct the formation of an enzyme or other protein.

Gene Therapy
Use of Genetically Modified Stem Cells in Experimental Gene Therapies

Genetics, the introduction to:
Genetics is a discipline of biology. It is the science of heredity. This includes the study of genes, and the inheritance of variation and traits of living organisms. In the laboratory, genetics proceeds by mating carefully selected organisms, and analysing their offspring. More informally, genetics is the study of how parents pass some of their characteristics to their children. It is an important part of biology, and gives the basic rules on which evolution acts.

The fact that living things inherit traits from their parents has been known since prehistoric times, and used to improve crop plants and animals through selective breeding. However, the modern science of genetics, which seeks to understand the process of inheritance, only began with the work of Gregor Mendel in the mid-nineteenth century. Although he did not know the physical basis for heredity, Mendel observed that organisms inherit traits via discrete units of inheritance, which are now called genes.

Genomics is a discipline in genetics that applies recombinant DNA, DNA sequencing methods, and bioinformatics to sequence, assemble, and analyze the function and structure of genomes (the complete set of DNA within a single cell of an organism).

Germ Cell:
A germ cell is any biological cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate near the gut of an embryo and migrate to the developing gonads. There, they undergo cell division of two types, mitosis and meiosis, followed by cellular differentiation into mature gametes, either eggs or sperm.

Germ Layer:
A germ layer, occasionally referred to as a germinal epithelium, is a group of cells, formed during animal embryogenesis. Germ layers are particularly pronounced in the vertebrates; however, all animals more complex than sponges produce two or three primary tissue layers (sometimes called primary germ layers). Animals with radial symmetry, like cnidarians (species of animals found exclusively in aquatic and mostly marine environments), produce two germ layers (the ectoderm and endoderm) making them diploblastic. Animals with bilateral symmetry produce a third layer between these two layers (appropriately called the mesoderm) making them triploblastic. Germ layers eventually give rise to all of an animal's tissues and organs through the process of organogenesis.

German Stem Cell Research:
The Germans are light years ahead of The US in stem cell research. Read why.

Glial cells, sometimes called neuroglia or simply glia, are non-neuronal cells that maintain homeostasis, form myelin, and provide support and protection for neurons in the brain, and for neurons in other parts of the nervous system such as in the autonomic nervous system.

Glycoconjugates is the general classification for carbohydrates covalently linked with other chemical species such as proteins, peptides, lipids and saccharides.

Glycosaminoglycans (GAGs) or mucopolysaccharides
Are long unbranched polysaccharides consisting of a repeating disaccharide unit. The repeating unit (except for keratan) consists of an amino sugar (N-acetylglucose amine or N-acetylgalactose amine) along with a uronic sugar (glucuronic acid or iduronic acid) or galactose.

Golgi apparatus:
Also known as the Golgi complex, Golgi body, or simply the Golgi, is an organelle found in most eukaryotic cells. It was identified in 1897 by the Italian physician Camillo Golgi and named after him in 1898.

Part of the cellular endomembrane system, the Golgi apparatus packages proteins inside the cell before they are sent to their destination; it is particularly important in the processing of proteins for secretion.

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