Final answer:
To determine the mitotic index, count the number of cells in mitosis and divide by the total number of cells. Estimate the length of each stage in the cell cycle by the proportion of cells in each stage. Test this with a stained sample of cells under microscopy.
Step-by-step explanation:
Determining the Mitotic Index
To determine the mitotic index from a micrograph, a researcher would count the number of cells in mitosis (option C) and divide by the total number of cells observed. The stages of mitosis include prophase, prometaphase, metaphase, anaphase, and telophase, which can be identified by specific structural changes visible under a microscope.
To estimate the length of each cell cycle stage, a hypothesis could be made based on the number of cells observed in each stage relative to the total cell count. The stages of interphase (G1, S, and G2) are part of the cell's preparation for mitosis but are visually less distinguishable than the mitotic phases. Through quantifying and comparing these numbers, one can hypothesize about the duration of each cell cycle stage.
Finally, to test this hypothesis, you would prepare a slide of cells, such as a whitefish blastula cross-section, stain it to reveal cellular structures, and then observe and count the number of cells in each stage using a microscope. Dividing the count of cells in a specific stage by the total cell count and multiplying by the total cycle time (e.g., 24 hours) can give an estimated time spent in that stage.