Pretest: Heredity
The Correct Answer and Explanation is:
Based on the diagrams of cell division, here are the correct labels for each stage:
- Top Image: Anaphase of Mitosis
- Second Image: Telophase and Cytokinesis of Mitosis
- Third Image: Metaphase I of Meiosis
- Bottom Image: Metaphase of Mitosis
Explanation
The images you provided illustrate distinct stages of mitosis and meiosis, which are critical processes for heredity, growth, and reproduction. Understanding these phases is key to understanding how genetic information is passed on.
The first diagram at the top depicts Anaphase of Mitosis. In this stage, the defining characteristic is the separation of sister chromatids. These identical copies of each chromosome are pulled apart by the spindle fibers and move to opposite poles of the cell. This ensures that each resulting daughter cell will receive a full, identical set of chromosomes. The cell also elongates in preparation for its final division. This process is essential for creating new somatic, or body, cells for growth and tissue repair.
The second diagram shows Telophase and Cytokinesis of Mitosis. This is the concluding phase of mitosis. The separated chromatids, now considered individual chromosomes, have arrived at the cell poles. Two new nuclear envelopes begin to form around the two sets of chromosomes. Concurrently, the process of cytokinesis splits the cytoplasm, cleaving the cell into two separate, genetically identical diploid daughter cells.
The third diagram illustrates Metaphase I of Meiosis. This stage is unique to meiosis, the process that produces gametes or sex cells. Here, homologous chromosome pairs, not individual chromosomes, align at the center of the cell, known as the metaphase plate. This pairing is crucial for genetic recombination. The random orientation of these pairs, called independent assortment, and the prior crossing over of genetic material create genetically unique daughter cells, which is the foundation of genetic diversity in sexual reproduction.
The fourth and final diagram represents Metaphase of Mitosis. During this phase, individual chromosomes, each made of two sister chromatids, line up in a single file along the metaphase plate. This precise arrangement is a checkpoint to ensure that when division proceeds to anaphase, the sister chromatids will separate evenly into the two new cells
