Mitosis and Meiosis

     More than one celled organisms grow by way of mitosis and the cytoplasmic division of body cells. On the other hand, meiosis occurs only in germ cells, which are put aside for the formation of gametes (sperm and egg). Reproduction by meiosis allows for species survival and it increases genetic variability.

Meiosis consists of one DNA replication and two nuclear divisions resulting in 4 daughter cells. The process which provides for genetic variation is crossing over. Crossing over occurs in the early stages when homologous chromosomes move together so that their chromatids form a tetrad. This is called synapsis and allows for the exchange of chromosome sections.

Mitosis: This is the process by which a cell duplicates the chromosomes in its cell nucleus in order to generate two identical daughter nuclei.

Compare and Contrast Mitosis and Meiosis Meiosis and mitosis describes the process by which cells divide, either by asexual or sexual reproduction to produce a new organism. Meiosis is a form of cell division that produces gametes in humans these are egg cells and sperms, each with reduced or halved number of chromosomes. The number of chromosomes is restored when two gametes fuse together to form a zygote. A cell with two copies of each chromosome is called diploid cell and a cell with one copy of each chromosome is called a haploid cell.

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

17) The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called

Response Feedback: Meiosis occurs only in replicating gametes or reproducing cells. In phase one, the number of chromosomes is reduced by half but the chromatid pairs remain together. In phase two, the chromatids split apart forming four daughter cells. Non-germ cells such as red blood cells or skin cells undergo mitosis.For more information on this topic, consult:Carol Mattson Porth and Glen Matfin, Pathophysiology, 8th Edition,

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

There is an additional cost of reduce fitness for organisms in which the genders are separate. Also, there is another cost known as the cost of meiosis, which means that in sexual reproduction, only half of the genes are passed on to the next generation. On the other hand, there are some important benefits in sexual reproduction including purging harmful mutations and creating genetic variation that assistances offspring deal with the variations in the environment. In contrast, asexual reproduction creates clonal offspring only if the parents are perfectly adapted to the

Similar to mitosis, the homologue pair move line up across the equator and microtubules bind to them. This process is also distinct from mitosis because in mitosis the spindles bind to the chromatids, but in meiosis I, the spindles bind to the pairs (Khan Academy). Once the homologue pairs are in position, the microtubules will pull the pairs apart in what is called Anaphase I. Once this phase is completed, telophase I is initiated. This is where the cell actually divides. Cytokinesis, which is the actual separation of the cell, occurs and forms two daughter cells (Khan Academy). These two cells are called haploid cells because they have only one set of chromosomes whereas the original cell was a diploid cell because of the homologue pairs.

Sex is a mode of reproduction and a way for a large number of organisms to reproduce. But is sexual reproduction really advantageous? There are advantages and disadvantages to sexual reproduction.

In mitosis, a parent cell divides in half leaving two daughter cells which are genetically identical to itself. Mitosis occurs in four separate stages called prophase, metaphase, anaphase, and telophase. Starting in prophase, the mitotic spindle (which eventually pulls the chromosomes apart) starts to form and catch the condensed chromosomes and the nucleolus disappears. After the mitotic spindle is complete and full, metaphase begins with the chromosomes lining up at the center of the spindle and ends with the spindle double checking that the chromosomes are attached to the microtubules which are connected to the kinetochores. If the check is not complete, the whole cell division process is halted until it is fixed. Anaphase is the section where the cell started to divide by the sister chromatids pulling apart to opposite ends of the spindle. In telophase, everything is cleaned up and normal cell structures start to form again as the cells finish dividing and return to their normal functions (Khan

Meiosis is a two part cell division (meiosis 1 and meiosis 2) process that produces four daughter cells, each having half the number of chromosomes of the parent cell—such as the product of

One of the vital processes, which are very important for cells’ life, is called cell division. There are two types of it called mitosis and meiosis. In this practical, we will focus on mitosis. Mitosis is a part of eukaryotic cell division cycle, when a nucleus divides into two new nuclei. Prokaryotic cell does not have nucleus, so mitosis does not occur there. According to Kent (2000) and Campbell (2009), mitosis consisted of four steps: Prophase, Metaphase, Anaphase and Telophase. Interphase is the preparation of cell to mitosis: growth of the cell and its’ organelles, replication of DNA occur during this period. Mitosis starts with prophase, when the chromosomes are coiled and become shorter, next stage is metaphase when chromosomes line