Notes On Osmosis And Diffusion

     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.

2) Why are onion root tip and whitefish blastula areas that are ideal to view mitosis?

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.

Interphase: This particular stage is divided into three phases, G1 (first gap), S (synthesis), and G2 (second gap). During all three phases, the cell grows by producing proteins and other organelles within the cytoplasm. However, chromosomes are replicated only during the S phase. In all, a cell grows (G1), continues to grow as it duplicates its

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.

Meiosis is the cell cycle for germ cells (gametes) where they are haploid (n) so that is why they have two sets of phases.

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

Cytokinesis – the division of the parent cells by cytoplasm to form two daughter cells caring identical genetic information

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.

Mitosis is one of two main methods of cell replication, the other being meiosis. It is “the simple duplication of a cell and all of its parts” resulting from the splitting of a cell. The ‘parent’ or original cell splits, duplicating its DNA (packaged in chromosomes) producing two ‘daughter’ or new cells with the same genetic code. There are four stages of mitosis; Prophase, Metaphase, Anaphase and Telophase. Interphase is not an official phase of mitosis as the cell is at ‘rest’ and not being divided during this phase. It is often called one of the phases of mitosis as it is one of the stages in the life cycle of a cell; however it is not a phase of mitosis due to the fact that no division takes place.

Cell division may happen by either mitosis or meiosis, depending on what type of cell is invovled. Mitosis is a process by which a cell divides to form two daughter cells. They each have the same exact number and kind of chromosomes as the parent cell. Meiosis occurs in the primary sex cells leading to the formation of viable egg and sperm cells. They reduce the number of chromosomes to half in each gamete so that when they are getting furtilized, the species chromosome number is kept even.

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,

In genetics, the way people retrieve their genes and traits is through cell division; mitosis and meiosis. Mitosis in cell division is the process in making body cells. There are 7 stages in mitosis; interphase, prophase, prometaphase, metaphase, anaphase, telophase, and cytokinesis. In interphase, the cell is growing normally and synthesizes with organelles. In prophase, changes occur in the cell and parts of the structures begin to break down, setting the stage for chromosome division. Prometaphase is the stage where the chromosomes are sorted and made very compact, and metaphase is when the chromatids of each chromosome are attached to a microtube to form a spindle. Anaphase it the process in which the chromosomes split, leading into telophase, which is where the chromatids travel to opposite poles in a cell and new membranes form around the nuclei. The final stage in mitosis, cytokinesis, is when the chromatids split in two.