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 […]

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 […]

The octopus is an invertebrate animal from the phylum Mollusca (soft-bodied animals, which may or may not be protected by a shell), and within this from the class Cephalopoda. It occurs in marine environment, and has a wide distribution – it can be found in tropical and temperate regions and at different depths. The common […]

Okazaki Fragments definition Okazaki Fragments refers to small single stranded DNA fragments, formed upon DNA replication, more specifically, the back strand.   DNA Replication/Duplication For normal cell growth and division in organisms, an initial step called DNA replication is required. This process is based on semi-conservative copy of DNA in the nucleus of a growing […]

Oocyte I definition Oocyte I designates a female germline diploid cell that forms during the cycle called oogenesis. Mammalian oocytes I enter phase I of meiosis during fetal development. Oocyte I development Oocyte I develops during oogenesis, a cycle through which oogonium develop and produce ovum. This cycle begins in fetal development, where primordial germ […]

Oocyte II definition Oocyte designates a female germline diploid cell that forms during the cycle called oogenesis and derives from oogonium growth. In mammals and most species, oocyte II is a haploid cell derived from the maturation of oocyte I in oogenesis. Oocyte II development At the end of meiosis phase I, in oogenesis, oocyte […]

The osteoblast, cell found within bone tissue, is responsible for bone synthesis and mineralisation over the formation of the skeleton and further bone remodelling (…)

The osteoclast is one of the bone cells. Its function is the resorption of bone tissue over a process called remodelling (…)

Definition of ovum The ovum (or egg cell, figure 1) is the mammalian female gamete (haploid cell), produced in the ovary through a process called oogenesis. This cell is characterized by being a giant cell that contains most of the constituents necessary to give rise to a new organism. Development of the ovum At the […]