The two centrioles in the centrosome lie perpendicular to each other. Each has organisation like a cart wheel. These form the basal body of cilia and flagella of plant/animal cells besides forming spindle fibre in animal cell division. It also helps in the formation of microtubuless and sperm tail.

The DNA present in mitochondria and chloroplast is extrachromosomal DNA. It has nothing to do with the nuclear divisions. In mitosis, only nuclear DNA takes part.

The diagram shows the transition stage between prophase and metaphase stage of mitotic cell division.

The mitotic cell division occurs in somatic cells of an organism. The chromosome number in the daughter cells remain same as that of the parent (dividing) cell, so even at metaphase or anaphase, the chromosome number does not change. The DNA content gets doubled at the synthetic phase of interphase and gets divided at anaphase but the chromosome number remains same.

Such a condition may arise in case of a mosaic or mosaicism, which denotes preserve of two or more populations of cells with different genotypes in one individual. It can result from various mechanisms including non-disjunction, anaphase lagging and endoreplication. It may also result from a mutation during development which is propagated to only a subset of the adult cells. In this case, cells with 16 chromosomes could have arisen from cells with 32 chromosomes.