For example, your standard fixed overhead cost is $3 per unit. If your actual fixed overhead cost is $4 per unit, you have an unfavorable variance of $1. You spent $1 more per unit than you had originally budgeted.
In biology, histones are highly alkaline proteins found in eukaryotic cell nuclei that package and order the DNA into structural units called nucleosomes. They are the chief protein components of chromatin, acting as spools around which DNA winds, and playing a role in gene regulation. Without histones, the unwound DNA in chromosomes would be very long (a length to width ratio of more than 10 million to 1 in human DNA).
Thus, within the nucleus, histones provide the energy (mainly in the form of electrostatic interactions) to fold DNA. As a result, chromatin can be packaged into a much smaller volume than DNA alone. Histones are a family of small, positively charged proteins termed H1, H2A, H2B, H3, and H4 (Van Holde, 1988). DNA is negatively charged, due to the phosphate groups in its phosphate-sugar backbone, so histones bind with DNA very tightly.