Mitosis and Meiosis Practical Report

     The leptotene. This phase differs only slightly from the early stages of mitosis. Usually are the cells and nuclei of meiotic tissues bigger than that of their neighbouring tissues and often do they seem to be longer and are longitudinally structured. At regular intervals can thickenings be found, like beads on a string: the chromomeres. Their number, size and positioning is constant in each species.

Exercise 3A is a study of mitosis. You will simulate the stages of mitosis by using chromosome models.You will use prepared slides of onion root tips to study plant mitosis and to calculate the relative duration of the phases of mitosis in the meristem of root tissue. Prepared slides of the whitefish blastula will be used to study mitosis in animal cells and to compare animal mitosis and plant mitosis.

2.) Based on the data table, what can you infer about the relative length of time an onion root tip cell spends in each stage of cell division?

Mitosis and meiosis are similar in several ways and different in others. The similarities include that both processes involve IPMAT. IPMAT is interphase, prophase, metaphase, anaphase and telophase. The parent cells are diploid. They both end with cytokinesis. In Metaphase and Metaphase II, the sister chromatids line up along the center. Then in Anaphase and Anaphase II, these chromatids are split and pulled towards the centrosomes. The differences are that mitosis consists of 1 division while meiosis consists of 2. Four genetically different, haploid sex cells are the products of meiosis and 2 identical, diploid somatic cells from mitosis. Mitosis occurs in all organisms except viruses and meiosis only occurs in plants, animals, and fungi.

A) Meiosis consists of two cell divisions and is broken up into Meiosis I and Meiosis II. At the beginning of the Cell Cycle, in this case there are four chromatids each from the homologous pairs being A, a, B, b. This is the Diploid number (4) meaning it is 2 times the haploid number that will be seen at the end of meiosis II. During the S phase of interphase, the chromatids replicate and reach the end of G2 phase. Now starting meiosis, during the first stage of prophase I the chromosomes condense and pair up through synapsis with their sister chromatids creating AA, aa, BB, bb. After they pair up they go through a process called crossing over, where the homologous chromosomes share a piece of their genetic material with each other. Crossing over allows for the genetic diversity of chromosomes. Now there are four homologous chromosomes Aa, Aa, Bb, Bb, each containing heterozygous alleles because the sister chromatids exchanged genetic information with their homologous pair. During late prophase I, spindle fibers being to form where they will later attach to a homologous chromosomes centromere. The next stage is Metaphase I. During metaphase I, the homologous pairs line up at the metaphase plate, also known to be the center of the cell. The homologous pairs form a tetrad which is considered a group of four homologous chromosomes. These homologous chromosomes orient themselves randomly, which is know as the process of independent

Although mitosis is just a fraction of time compared to interphase it can be divided into four distinct subphases. If we start viewing a cell under a brightfield microscope right at the end of interphase subphase G2 we would see that throughout the interphase process (fig 1) the cell has grown considerably in size due to production of extra mitochondria and endoplasmic reticulum. The cell has also gone through the labor of duplicating all of its chromosomes, a process known as DNA synthesis. Now that the cell has made all of these preparations it's time to start prophase (fig 2), the first stage of the mitotic phase. This stage is visibly identified by the chromatin becoming the tightly formed chromosomes. During the lab we were able to view these newly formed chromosomes best on the onion root tip

9. Using your data, calculate the time required for the completion of each stage of mitosis in onion root tip cells. Be sure to use the totals for all three count areas. Record these calculated results in the appropriate column of Data Table 1.

Mitosis is the process of duplicating nuclear material one cell becomes two cells. A cell contains 46 chromosomes, this is known as diploid. This process involves prophase, metaphase, anaphase, and telophase. Mitosis ensures the continuation of the organism and helps the body build and repair. Meiosis on the other hand is for production of haploid cells, 23 chromosomes, that together with another human, new organisms are created.

To observe mitosis in onion root tip cells and record the different phases of mitosis.

This study was performed in order to gain more knowledge on mitosis and meiosis. This lab was done by observing mitosis in plant and animal cells, comparing the relative lengths of the stages of mitosis in onion root tip cells, stimulating the stages of meiosis, observing evidence of crossing-over in meiosis using Sordaria fimicola, and estimating the distance of a gene locus from its centromere. Mitosis is the scientific term for nuclear cell division, where the nucleus of the cell divides, resulting in two sets of identical chromosomes. Mitosis is accompanied by cytokinesis in which the end result is two completely separate cells called daughter cells. There are four phases of mitosis: prophase, metaphase, anaphase and

When studying the onion root tip slide, where will you focus to find the most dividing cells? The zone of continual cell division called the

Meiosis and mitosis are very similar, they both go through the same stages at one point and use the same approaches and tactics when it comes to keeping the chromosomes away from each other. But meiosis has a much harder job than mitosis, yes in fact they both need to keep the sister chromatids away from each other but also keep the homologous chromosomes apart. The sister chromatids are the two parts of a duplicated chromosome and the homologous chromosomes are the alike but they are the non-identical pairs which an organism takes from the two parents.

There are many ways that mitosis and meiosis are similar such as them having always having a Prophase, Metaphase, Anaphase,Telophase (PMAT). In addition, both of them have their own interphase at the start of the PMAT. Also, since they have a PMAT then they will always create cells during it which would mean that PMAT will always repeat. Without Mitosis and Meiosis, the human population would already be extinct. Even though they have their similarities they also have their own differents.

During this exam I was thinking about the steps of both mitosis and meiosis. When it came to the exam I thought I had that question, but it turns out I didn’t. The actual process of mitosis is prophase, metaphase, anaphase, telophase/cytokinesis, and lastly the two daughter cells. Along with the steps I also got the difference between the two. Going into the test I thought I had a good enough explanation for it, then I got to the questions and I got it wrong. I put D, which was mitosis produces haploid cells, but meiosis produces diploid cells. The correct answer was B, with is mitosis produces cells genetically identical to the plant cell, but meiosis does not. After reading both answers I understand the difference between the two.

The main focus of this lab was to be able to understand the different phases of mitosis and the cell cycle and also identify what those stages may look like. Mitosis is the process in which concerns the production of new cells. For example, when apoptosis(cell death) the process of Mitosis begins to replace the dead cells. To be able to familiarize ourselves with this concept, we took a sample of an onion root and had it put through a process to be able to look at the different phases under the microscope. We found that the majority of the cells were mostly undergoing Interphase or Prophase which are the phases in charge of crossing over of DNA and where the chromosomes then become visible and the nuclear envelope dissipates. The conclusion of this lab was that Mitosis is essential for the production of new cells. In the case of the onion root sample, the cells were damaged leading to the tester to undergo Mitotic cell division and it was found that mainly Interphase and Prophase were the stages that occurred in this lab.