Mitosis Essay Research Paper In order for

Mitosis Essay, Research Paper

In order for a cell.s surface area to provide its volume with sufficient nutrients, a cell must grow and divide. This division, along with the four other phases of mitosis, make up the whole cell cycle. In this graph, .Cell Division & Its Divisions,. we will explore the many different elements, relationships, and points of importance involved in the cell cycle.

The first phase of the cell cycle is known as interphase, which is the longest phase of the five. Interphase contains three subphases: G1, S, and G2. G1, also known as the growth mode, lasts approximately eight hours. It is the period of major cytoplasmic activity and growth within the cell, which reduces the surface area : volume ratio. The G represents Gap, or a break between cell divisions. However, this is not a period of rest. It is rather a period of rapid growth, especially in younger human cells. During G1, the amount of DNA per cell remains the same at y as the cell grows continually. The cell.s radius increases steadily because of the its cytoplasmic growth. The cell.s MTE, or Membrane Transport Efficiency, is a measure of how well a cell is able to transport nutrients and wastes through its membrane. If the MTE drops below its .comfort level,. or the level in which the cell can transport these things, it is in danger unless it divides soon afterwards. If the MTE drops below its .death level,. which is very low, the cell will die from lack of nutrients and excessive wastes. During G1, the MTE decreases and reaches the .comfort level. by the end of the phase. The end of G1 depends on the rate at which the cell.s MTE drops and passes its .comfort level..

The S phase begins the division mode of interphase. This is where the DNA within cells are replicated to provide both daughter genes with their needed genes. This subphase lasts approximately six hours, bringing us to the 14 hour mark of the cell cycle. During the S subphase, the amount of DNA per cell constantly increases until it has doubled itself, reaching 2y. The cell.s radius still increases throughout the S subphase, but it does so at a slower rate than during the G1 subphase. The cell.s MTE decreases at a slower rate than it had been during the latter subphase, but this decrease brings the MTE below the .comfort level.. This means that the cell should divide soon or else major problems will occur. The DNA replication process has been executed and achieved!

The final division of interphase is the G2 subphase, which prepares the cell for its division. G2 lasts approximately four hours, which makes it the shortest subphase of interphase. During this subphase the cell continues to grow and it makes proteins needed for the cell division process. The G2 subphase continues the division mode of interphase. During G2, the amount of DNA per cell ceases to replicate itself and remains the same at 2y as the cell grows continually. The cell.s radius is still growing larger, but at an even slower rate than that of the S subphase. The cell.s MTE decreases constantly at even a slower rate than that of its latter subphase. Oh no! This is not good news for the cell.s transport efficiency, but at least the MTE level is a safe distance away from its .death level!. Interphase has ended and the cell is now fully prepared for its division. I.m so excited!

After 18 long hours of interphase, the cell is ready to divide by the process of mitosis. Mitosis includes four phases: prophase, metaphase, anaphase, and telophase. This process lasts only approximately 45 minutes, but a lot can happen in that short amount of time. The amount of DNA per cell begins its sudden and rapid decline down to y, its starting point. This splits the amount of DNA in half to provide both daughter cells with the sufficient number of genes. The cell.s radius continues to grow until mitosis is almost complete. Then the radius divides itself among the two daughter cells and finishes where it began to start growing again. The cell.s MTE continues to decrease, getting closer and closer to its .death level.. However, at the very last stages of mitosis, the MTE increases rapidly and ends up at its starting point to begin decreasing once again. Mitosis has ended successfully.

Due to the cell cycle, one cell has brilliantly divided itself, including its radius, number of organelles, chromosomes number and amount of DNA per cell. As a result, the cell.s surface area : volume ratio and MTE are increased, which also improves the quality of the cell.s life. Now both daughter cells are immediately ready to begin the cell cycle again.

A student knows that cells from a particular species have 18 chromosomes as their diploid number. This student observed two daughter cells from a recent mitosis, and noted that one had 19 single chromosomes and the other had 17. Apparently some failure in the mitotic process occurred. The most likely and most logical explanation for this abnormality was that the in one double chromosome, centromere separation failed to occur at the end of metaphase, but did occur at some later time in the cell division process.

The reason for this mitotic abnormality was not that cytokinesis failed to occur at the end of telophase. Cytokinesis is known to be somewhat imprecise, which would explain the misplacement of a cell part. However, cytokinesis only distributes the divided cytoplasm and its organelles to