About one-third of the retail trade industries â $7.5 million in average annual receipts. A few, such as grocery stores, department stores, motor vehicle dealers (except new car dealers) and electrical appliance dealers have a higher size standard, ranging from $11 million to $38.5 million in average annual receipts.
spindle fibers. Spindle fibers form a protein structure that divides the genetic material in a cell. The spindle is necessary to equally divide the chromosomes in a parental cell into two daughter cells during both types of nuclear division: mitosis and meiosis. During mitosis, the spindle fibers are called the mitotic spindle.
Definition: Spindle fibers are aggregates of microtubules that move chromosomes during cell division. During prophase of mitosis, spindle fibers form at opposite poles of the cell. During metaphase, spindle fibers extend from the cell poles toward the midpoint of the cell known as the metaphase plate. Chromosomes are held at the metaphase plate by the equal forces of the spindle fibers pushing on the centromeres of the chromosomes. In anaphase, spindle fibers pull sister chromatids toward the spindle poles. Spindle fibers not connected to chromatids lengthen and elongate the cell.