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Cell migration is a central process in the development and maintenance of multicellular organisms.Tissue formation during embryonic development, wound healing and immune responses all require the orchestrated movement of cells in particular directions to specific locations.
a Cells of the same lineage fuse to form a cell with multiple nuclei, known as a syncytium. The fused cell can have an altered phenotype and new functions such as barrier formation. b Cells of different lineage fuse to form a cell with multiple nuclei, known as a heterokaryon. The fused cells might have undergone a reversion of phenotype or ...
Anisogamy is the form of sexual reproduction that involves the union or fusion of two gametes which differ in size and/or form. [12] The smaller gamete is considered to be male (a sperm cell), whereas the larger gamete is regarded as female (typically an egg cell, if non-motile).
For humans, we're 99.9 percent similar to the person sitting next to us. The rest of those genes tell us everything from our eye color to if we're predisposed to certain diseases.
If life is viewed from the point of view of replicator molecules, cells satisfy two fundamental conditions: protection from the outside environment and confinement of biochemical activity. The former condition is needed to keep complex molecules stable in a varying and sometimes aggressive environment; the latter is fundamental for the ...
The different stages of mitosis altogether define the mitotic phase (M phase) of a cell cycle—the division of the mother cell into two daughter cells genetically identical to each other. [3] The process of mitosis is divided into stages corresponding to the completion of one set of activities and the start of the next.
The history of life on Earth traces the processes by which living and extinct organisms evolved, from the earliest emergence of life to the present day. Earth formed about 4.5 billion years ago (abbreviated as Ga, for gigaannum) and evidence suggests that life emerged prior to 3.7 Ga. [1] [2] [3] The similarities among all known present-day species indicate that they have diverged through the ...
Cells contain hereditary information that is carried forward as a genetic code during cell division. [140] There are two primary types of cells, reflecting their evolutionary origins. Prokaryote cells lack a nucleus and other membrane-bound organelles, although they have circular DNA and ribosomes. Bacteria and Archaea are two domains of ...