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.
To see prophase animated, click the image. 1  Chromosomes become more coiled and can be viewed under a light microscope. 2  Each duplicated chromosome is seen as a pair of sister chromatids joined by the duplicated but unseparated centromere. 3  The nucleolus disappears during prophase. In the cytoplasm, the mitotic spindle, consisting of microtubules and other proteins, forms between the two pairs of centrioles as they migrate to opposite poles of the cell. The nuclear envelope disappears at the end of prophase. This signals the beginning of the substage called prometaphase.