Mitosis & Meiosis
MitosisGoogle Images
Mitosis results in two identical daughter cells. There are five main phases during this form of cell division;they are G0, G1, S, G2, Mitosis and Cytokinesis. During the mitosis phase there are four phases within; prophase, metaphase, anaphase and telophase. G0- This can be considered a resting period. G1- The cells increase in size during this phase. It makes sure the cell is ready for DNA synthesis. There is a checkpoint at the end of this phase. This checkpoint is a chemical one; it determines if the cell is on the right track to divide. S- During this phase all the DNA is replicated. This is so when there are the cell separates into two daughter cells they will have the exact same DNA in them. G2- The cell continues to grow. There is a check point at the end of this phase. This checkpoint makes sure the cell is able to move into the next phase and divide. Mitosis- During this phase the two sets of genetic information are separated in order to be sent to the two daughter cells. Growth does not happen in this phase. During the last portion, the cell divides into two identical daughter cells. There are phases within Mitosis. There is prophase, metaphase, anaphase, and telophase. During prophase, the DNA condenses by coiling. The nuclear membrane begins to dissolve and the spindle apparatus appear. During metaphase, spindle fibers pull to line up chromosomes. During anaphase, chromosomes heard in opposite directions. During Telophase, chromosomes uncoil, the nuclear membrane reforms and the spindle apparatus disappears. Cytokinesis- Most of this phase overlaps with the last portion of Mitosis. The cell divides into two identical daughter cells |
MeiosisGoogle Images
Meiosis results in four genetically different haploid cells. In meiosis homologous chromosomes replicate. These replications are called sister chromatids. Homologous chromosomes are different than sister chromatids. Homologous chromosomes are chromosomes that carry the same genes, but not the same alleles. Sister chromatids not only carry the same genes on the, but all the same alleles. Sister chromatids connect at the centromere while homologous chromosomes really never join together except during the first prophase where crossing over occurs. They line up with their homologous chromosomes and crossing over occurs. Crossing over is when DNA material is swapped between two homologous chromosomes. This allows for more genetic variation. From there the homologous chromosomes separate from one another. The cells cleave results in two cells. That is Meiosis I. Then in Meiosis II the sister chromatids are independently assorted, separate and once again the cell cleaves. This results in the four genetically different haploid cells. Helpful Sites Cells Alive |
Chromosome Duplication
This is an upclose look at a chromosome and it's sister chromatid. Chromosome duplication happens in Mitosis and Meiosis I.
-GVSU BIO 205 Lecture J. Vigna
-GVSU BIO 205 Lecture J. Vigna
Mitosis & Meiosis Videos
Below are links to interesting, informative videos that help better explain the somewhat confusing topics of mitosis & Meiosis
Mitosis and Meiosis Bead Simulation
McGraw-Hill Mitosis Simulation
Meiosis Square Dance
Mitosis Dance
Mitosis and Meiosis Bead Simulation
McGraw-Hill Mitosis Simulation
Meiosis Square Dance
Mitosis Dance