Stem cells are the primal cells which develop from adult body tissues and embryos. These are present in the adult body through out their life. These are also called tissue specific or somatic stem cells. These are more specialised than embryonic stem cells. These stem cells are found in bone marrow, brain, blood and blood vessels, skeletal muscles, skin and the liver. Differentiation is the process where an unspecialised cell acquire cellular character which allows it to perform specialised functions. During embryonic stage, the cells of embryo make a number of cell fate decision that result in the decreasing capability eventually producing the specialised cells. Stem cells can divide and produce new cells, Hence they have the potential to be transplanted to the patient to treat medical conditions and disease. They are removed form the embryo where they exist as unspecialised stem cells and they will differentiate into any cell type. Specialised cells include many cells like nerve cells, blood cells, ovum cells etc. These specialised cells help in reproduction, energy metabolism, regeneration, information transfer etc.
The rate at which a parent atom creates daughter atoms is always constant and unique.
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Without genetic variation there would not be evolution. genetic variation sometimes is a result of a change in the environment. some variation occurs to help the animal better survive in their habitat. maybe there was a disruption in their ecosystem and their species will become vulnerable unless they change somehow
Petit-mal seizure
Petit mal seizure is a form of
epilepsy with short sudden, unannounced lapses in consciousness. Impairment of
consciousness is the essential symptom. The sufferer experiences loss of
consciousness for 10 to 30 seconds, eye or muscle flutterings and a loss of
muscle tone.
A single animal cell ( like a red blood cell) placed in a hypotonic solution will fill up with water and then burst.