Final answer:
The aster in whitefish blastula is a star-shaped structure around the centrosome visible during metaphase of mitosis, which can be identified under high-power magnification in a microscope slide of whitefish blastula cross-sections.
Step-by-step explanation:
The aster in whitefish blastula refers to a star-shaped structure that forms around the centrosome during mitosis in cell division. This structure is most visible during the mitotic stage known as metaphase, where the spindle fibers radiate outwards. In a whitefish blastula cross-section prepared for microscope examination, the aster can be identified as part of the mitotic apparatus associated with the spindle formation during cell division.
To locate and identify the aster, you would begin by examining cells under a light microscope, starting with a low-power objective to find the blastula cross-section and then switching to a high-power objective to clearly see the individual cells and their mitotic stages. When a cell is in the metaphase of mitosis, the aster will be recognizable due to the arrangement of spindle fibers emanating from the poles of the cell, surrounding the centrosomes.
The study of mitotic stages in the whitefish blastula is important for understanding cell division and can be used to estimate how long cells spend in each stage. By multiplying the percentage of cells in each stage by 24 hours, researchers can get an estimate of the time cells spend in each stage of the cell cycle.