The myelin sheath that covers many cns axons is formed by oligodendrocytes.
Oligodendrocytes are type of neuroglia (non-neural cells found in central nervous system) with protective, trophic and supportive role. Their function is to insulate axons (with myelin sheath), in the central nervous system (CNS) which is, equivalent to the function performed by Schwann cells in the peripheral nervous system (PNS).
Answer:
Anaphase of meiosis II
Explanation:
I think you are asking during which phase of cell division sister chromatids are mostly likely to fail to separate properly, a phenomenon that can lead to genetic disease.
This is sometimes called non-disjunction, and it is most likely to occur in anaphase during meiosis II. During this stage, sister chromatids of the two daughter cells produced by meiosis 1 are separated and brought to opposite parts of the cell. If something goes wrong at this stage, the sister chromatids can fail to separate properly, meaning the daughter cells do not have the correct number of chromosomes (see attachment).
An example of such a genetic disorder is Down syndrome
Whats the question that is the biology question
If a point mutation does not change the amino acid, it's called a SILENT mutation. If a point mutation changes the amino acid to a “stop,” it's called a NONSENSE mutation. Hope this helped :)