The type of bonds that are involved in these transient protein - DNA interactions include: IONIC BOND, VANDER WAAL FORCES AND HYDROGEN BOND.
Protein - DNA interaction occur when a protein bind to DNA molecule; this reaction usually occur in order to regulate the function of DNA, especially that of expression of genes. Protein interaction with DNA may be specific or non specific.
Sister chromosome exchanges are recombination events that occur between homologous chromosomes and are often the result of exposure of the cell to DNA damaging agents.
Cross over, or recombination, is the exchange of chromosome segments between non sister chromatids in meiosis. Crossing over creates new combinations of genes in the gametes that are not found in either parent, contributing to genetic diversity.
The same principle apply to stereo microscopes, a 10X eye piece combined with a 4X objective lens will produce 40X magnification.
