Mitochondria definition Mitochondria refers to a cellular organelle responsible for production of energy (ATP) necessary for cell optimal functioning. Mitochondria origin and synthesis The existing theory suggests that mitochondria is a semiautonomous organelle, which was originated in endocytosis of a bacterium by an ancestral nucleated cell. This theory, not yet fully confirmed, is called the […]

Mitochondrial DNA definition Mitochondrial DNA (mtDNA) refers to the DNA that is located inside the mitochondria, an organelle present in eukaryotic cells. MtDNA is double stranded but, unlike nuclear DNA, is circular, not packaged in chromatin, the translation of its codons into proteins does not follow the rules of the universal genetic code and has […]

Model Organism’s Concept The study of cellular mechanisms, genes, heredity and development of species were only possible due to the use of model organisms. Model organisms are non-human species whose genomes are known and which have genetic mechanisms common to a large group of related organisms. Gregor Mendel was the first to carry out studies using this […]

Molecular Biology is a branch of Biology that studies the cell at a molecular level. It has the main objective of studying the biochemical interactions between the different systems of the cell. It also studies in which way these interactions are regulated, focusing on the relationship between structure and function of genetic material (DNA and […]

Muscles are the largest set of body tissues and represent about half the weight of the body. Muscle tissue has a mesodermal origin and is composed of…

Mycobacterium tuberculosis is the etiologic agent of tuberculosis discovered in 1882 by Robert Koch and, as such, it is also called Koch’s bacillus.

Concept of necrosis The term necrosis refers to non-apoptotic, i.e. non-programmed, cell death. Cycle and cell death During its life cycle, cell undergoes several morphologic and structural changes. These changes are known and are characterized and divided into phases: interphase (constituted by G1 phase, S phase and G2 phase) and M phse (constituted by mitosis […]

Northern blot definition Northern blot refers to a technique used in Molecular Biology in which genetic expression is studied through detection of messenger RNA (mRNA) in a sample. This technique makes it possible to determine whether a gene is being transcribed into RNA or not. In addition, it is also possible determine the gene expression […]

Nucleosome definition Nucleosome refers to the fundamental structural unit of chromatin in the eukaryotic cell. It is this protein complex that gives the chromatin the ‘necklace of beads’ aspect. Cell nucleus and chromatine The cell stores all information necessary for its growth, metabolism and division into the nucleus, in the form of DNA. However, if […]

Occluding junction definition Occluding junction refers to the cell junction that seals the space between cells of an epithelium in such a way that it creates a barrier, which prevents the passage of molecules. Cell junctions Tissue cells are in constant communication due to existence of cellular junctions. There are various types of cell junctions […]