Study Guide: Mitosis and Meiosis
prepared by Kathleen Bartholomew
Mitosis is the process of dividing the replicated chromosomes of a single cell into two identical daughter cells. It is a part of cell division and happens during division of somatic cells. Mitosis is a form of asexual reproduction. It begins with a diploid cell, and ends with two diploid daughter cells. The number of chromosomes does not change in mitosis.
Prior to the beginning of mitosis, the DNA of the cell is replicated in S phase of interphase. In G2 of interphase, the DNA of the cell begins condensing (becoming tightly packaged), in order to be ready for mitosis. However, the chromosomes cannot yet be seen in G2. Remember: *DNA must be fully condensed in order to divide.*
M Phase is made up of mitosis and cytokinesis. The mitosis part has five phases: 1) prophase 2) prometaphase 3) metaphase 4) anaphase 5) telophase Following telophase is cytokinesis: division of the cytoplasm, organelles and macromolecules.
-DNA is completely condensed. We can see it…this means there are condensin proteins. -nuclear envelope is still present ** Look closely at the picture. The nuclear envelope will help you identify this stage. -mitotic spindle forms
-nuclear envelope breaks apart. You will not see it in this phase. The nuclear envelope is not destroyed but is re-used in telophase. -the breakdown of the nuclear envelope allows the microtubules from the mitotic spindle to access the chromosomes. -microtubules attach to kinetochore proteins. Kinetochores are the protein area of the centromere on each sister chromatid. The centromere is the area where both the sister chromatids contact one another. There are two kinetochores for each chromosome. -the cell has a circular shape
-mitotic spindle has moved chromosomes to the middle of the cell -**chromosomes are aligned at the metaphase plate (an imaginary line at the middle of the cell)** -all the microtubules...