Atom, organelles, molecules, and cell
Femur (thigh), Tibia (calf), Patella (kneecap).
Answer:
The Moon is closer than the Sun to Earth.
Explanation:
Answer: 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:
- Interface: The cell duplicates its organelles and its DNA to have twice everything before division.
- Prophase: The nuclear membrane breaks, the chromosomes condense, the centrosome duplicates and migrates to the opposite poles of the cell forming microtubules. Also, fibers of the mitotic spindle are formed.
- Prometaphase: The microtubules invade the space where the genetic material is.
- Metaphase: The replicated chromosomes line up in the middle of the cell, called the equatorial plane.
- Anaphase: Microtubules separate chromosomes towards the opposite poles.
- Telophase: The nuclear envelope is re-formed from the remaining fragments of the original.
- Cytokinesis: A cleavage groove is created in the common cytoplasm of the two new cells where the chromosomes were aligned. The cytoplasm is thus strangled until the membrane allows total separation.
<u>Mitosis is then a cellular process that occurs in multicellular organisms to repair damaged tissue, or for growth or development.</u> 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. <u>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.</u>
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, <u>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</u>.
Although the DNA packaging with histones proteins is mean to form nucleosomes (groups of 8 histones proteins), the higher structures why the genetic material is packaged with those molecules is to form chromosomes, as you said.
