Describe the situations in which a normal human cell would enter the cell cycle and undergo mitotic cell division. Explain how spindle fibers help ensure the products of mitosis are two identical cells with a full set of chromosomes.

An example of a specific case is when a skin lesion occurs. Through mitosis, new skin cells are generated to repair damaged tissue. These cells have to be genetically identical to each other. The spindle fibers are structures formed by microtubules extending from one pole to another to orient the duplicated chromosomes in the spindle, bringing them to the position they occupy during metaphase.

Explanation:

Mitosis is a process of cell division that occurs in eukaryotic cells, i.e. cells that have a nucleus where their genetic material is located. This process generates two identical cells with the same DNA, that is, with two identical nuclei, so it does not provide genetic variability except in case of specific mutations. The objective of mitosis is cell multiplication while preserving genetic information. But in general, in mitosis there is an equal distribution of the cell nucleus as well as the rest of the cell content.

The phases of mitosis are as follows:

Mitosis is then a cellular process that occurs in multicellular organisms to repair damaged tissue, or for growth or development. An example of a specific case is when a skin lesion occurs. When a person suffers an injury, many reactions take place in the repair process to repair the damage including inflammatory, proliferative, and remodeling phases.  Through mitosis, new skin cells are generated to repair damaged tissue. These cells have to be genetically identical to each other, to have the same genetic fingerprint and the same function.

The spindle fibers are structures formed by microtubules extending from one pole to another. The kinetochore microtubules attach to the kinetochore, a structure that forms at the centromere of each duplicated chromosome, and orient the duplicated chromosomes in the spindle, bringing them to the position they occupy during metaphase and attracting the newly separated chromosomes to the poles during anaphase.

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.