Biology Mitosis Lab

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.

2. At the end of meiosis, how many haploid cells have been formed from the original cell?

There should be an observable line of black dots, the mature perithecia, growing along the dividing lines that separate the four quadrants. Next, open the plate and using an inoculating loop, scrape some of the perithecia from the middle of one of the four dividing lines before depositing the sample onto a microscope slide. Use a squirt bottle of water to place a drop of water on top of the sample before covering it with a cover slip. Using a pencil eraser or your finger, apply slight pressure to the sample to release the asci from the perithecia without releasing the individual spores and slide around the cover slip to spread out the asci. Place the slide under a compound light microscope and observe the sample at 100X magnification in order to find the asci, before increasing the magnification to 400X for a clearer view. to Draw a sketch of the perithecium squash and asci in the results section. The final step of the experiment involves scoring (counting) ~10 clearly visible asci and recording how many of each of the three possible patterns of asci (4:4 (no recombination), 2:4:2, 2:2:2:2 (crossing over did occur)) there were in Table 1 of the results section. Following scoring one’s individual sample, clean up the inoculating loop, microscope slide, and cover slip, and put away the microscope. Collaborate with another person or group and combine individual data in

Research groups from the Imperial College of Science, Technology and Medicine and the Institute of Evolution at the University of Haifa have been studying the model organism, Sordaria fimicola, in regards to controlling cross over frequency in response to environmental pressures. Sordaria fimicola is a good model organism because it has a fast life cycle and elongated asci that are easily seen under a microscope. In addition, there are multiple different combinations of ascospore colors due to recombination during meiosis.

For a trisomic cell (when there is 2n+1), this new species would have 27 chromosomes. There could be an extra autosome or an extra sex chromosome.

There are three types of asexual reproduction known as, budding, regeneration, and parthenogenesis. Budding is the production of new individuals that form from bodies of older animals. Regeneration can either replace a damaged tissue or form another individual. An example of regeneration is flatworms. Lastly, parthenogenesis is the development of the offspring from unfertilized eggs. An example of parthenogenesis is honey bees or ants. In the evolution of sex cells divide because it replaces cells that have aged and died. Another reason for why cells divide is because it replaces cells that are lost or damaged known as regeneration. In a cell division chromosomes are replicated and it is passed on to daughter cells. The number of chromosomes

Sordaria fimicola is a commonly studied species of fungi from the phylum of Ascomycota, commonly known as the sac fungi or ascomycetes. Sordaria is more specifically studied in many mycology labs to gain a greater understanding of the exceptional formation of as many as 8 haploid ascospores. Normally Sordaria and other fungi exists as a haploid organism, but occasionally when the mycelium from two individuals meet, a diploid zygote is formed. The diploid cell is formed by the fusion of the haploid wildtype and one of the haploid mutant strain. After DNA replication, we are left with two sister chromatids connected with a centromere. During meiosis a process called synapsis occurs. Synapsis allows matching-up of two homologous pairs of chromosomes prior to their segregation, and possible genetic recombination amongst them by breaking and then reconnecting to the other chromosome thus allowing for crossing over to occur. The further away a gene is from the centromere, the more frequently the crossing over can occur. Both meiosis I and meiosis II generates four haploid products, and after one further round of mitosis, eight products are formed and all retained as haploid together forming a reproductive structure called a perithecium.

In this experiment cells with visible chromosomes were observed in order to find the percent of crossing over during meiosis. Many chromosomes maintain a 4:4 gene ratio but some do truly cross over. The chromosomes that showed a 4:4 ratio as well as the chromosomes that were crossed over were counted and entered into a data table for 2 plates. The map unit and percent of crossover were found using the data collected and also recorded in the chart.

The results of this lab showed the stages and events that occur in meiosis and mitosis. The four stages of mitosis were observed in the blastula staged whitefish embryo slides. The phases of mitosis are prophase, metaphase, anaphase, and telophase. The beginning stages that occur in mitosis take place in interphase, which are G_1, S, and G_2. In the G_1 stage, the cell begins to increase in size. After the size of the cell has increased it proceeds to the S stage where the chromosomes start to replicate themselves and attach together to the centromere. When the chromosomes are finished replicating themselves, it enters the G_2 stage where proteins check the integrity of the DNA. If everything is normal, the chromosomes are allowed to enter mitosis and begin the cell division process.

During prophase II is when spindle fibers begin to emerge, due to the condensing of chromosomes, and the disintegration of the nuclear envelope and nucleolus. In metaphase II, the individual chromosomes line up along the metaphase plate. One sister chromatid is drawn to each pole, in anaphase II, when the spindle fibers connected to each sister chromatid shorten. Around each haploid chromosome set a nuclear envelope is formed. The chromosome sets are split into new cells during cytokinesis, thus forming the four haploid cells in which each chromosome has just one chromatid. Sperm or eggs cells are the products of meiosis in humans.

Abstract A practical was conducted to observe the various stages of mitosis in the root tips of garlic. Mitosis is the process by which a parent cell divides to give two identical daughter nuclei. The main objectives were to achieve a better understanding of how to use a microscope and to help understand previous studies carried out on mitosis. It was not possible to see all the stages of mitosis under the microscope except for anaphase and metaphase.

The interphases of meiosis are similar to the interphase of mitosis. G phases are times of cell growth and preparation for division. The first division, meiosis 1. Consist of the following. Prophase 1, metaphase 1, anaphase 1, and telophase 1. The nuclear envelope starts to break down during prophase 1 of meiosis and microtubules are assembled. Previously replicate chromosomes are condensed to help them move around the cell without being tangled. These condensed chromosomes can only be seen under a microscope. The homologous pairs of chromosomes exchange genetic information. This is called crossing over. The homologous pairs line up in the center of the cell during metaphase 1. Near the

Mitotic division is the forming of two new daughter cell by a parent cell. Mitosis happens because cells need to repair and grow. The steps that mitotic division go through are prophase, metaphase, anaphase, telophase, and cytokinesis. Interphase also happens for mitosis to work, but it happens in the beginning before mitotic division starts. Mitosis only happens to somatic cells, and results in 46 chromosomes being in each new set of daughter cells.

In sexual reproduction, chromosomes can sometimes swap sections during the process of meiosis (cell division), thereby creating new genetic combinations and thus more genetic

According to the Biology-Online Organization (2006), Meiosis contained two type of phases meiosis I and meiosis II. In the prophase I, homologous chromosomes in the nucleus begin to pair up with one another and then split into chromatids where crossing over can occur. For metaphase I, the chromosomes will align at the equator of the cell. The bivalents are aligned randomly increasing the genetic variation via independent assortment. In the anaphase 1, the homologous chromosomes move to opposing poles from the equator. A new nuclei will be formed around each pole alongside each new chromosomes compliment in the telophase I. For prophase II, the second meiotic division will be initiated and the nuclear membrane will disappear. In the metaphase II, the pair of chromatids will be lined up at the equator. For the anaphase II, via the spindle fibers, each of these chromatids will be moved away from the equator to the poles. Lastly, in the telophase II the four new haploid gametes are created which will thus fuse with the gametes of the opposite sex to form a zygote.