How The Staining Of The Centromere Sequences Using Fish

Chromosome pairs line up across the equator of the spindle at metaphase I (5). In anaphase I the chromosomes separate and travel to opposite ends of the spindle. The chromosomes migrate to the equators of two new spindles for metaphase 2 (7). Next the chromatids are pulled apart in anaphase 2 to form four clusters of chromosomes in telophase 2. The nuclear envelopes reform around four haploid nuclei that will give rise gamete

a) As before follow instructions in the handout and draw pictures for each stage of Meiosis I an Meiosis II – color!

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.

These bivalents line up along the equator during metaphase I, the arrangement of the bivalent is completely random and relative to the orientation of the other bivalents, this is known as the independent assortment of chromosomes. This is followed by anaphase I where the homologous chromosomes separate and move to the opposite poles of the cell. At telophase I the cell divides into two, each cell contains one chromosome from each homologous pair. The second stage of meiosis is similar to mitosis.

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 results in four daughter cells (gametes) which have half the number of chromosomes of the original cell. They are therefore called haploid cell

Define the term crossing over. (3 points) During meiosis’ prophase the homologous chromatids exchange segments.

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

For this assignment, I will use the websites, lab and materials from this week and complete an internet search of my own on chromosomes. I will write a two- page essay that explains how conditions caused by extra or missing chromosomes reflect a meiotic error. I will also choose two conditions or diseases to review. Also, distinguish among the modes of inheritance.

Part B: Genes X, Y, and Z are linked. Crossover gametes between genes X and Y are observed

Anaphase – the chromosomes are divided into single from pair and the chromosomes move to opposite poles

A con for sexual reproduction is during meiosis. An egg and sperm cell usually have 23 chromosomes each. When an egg gets fertilized by a sperm cell it combines to 46 chromosomes. Human beings have 46 chromosomes each. When something goes wrong and a baby inside a womb gets one more extra chromosome, they get Down syndrome.

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 particular type of cell division results in the production of four daughter cells per parent cell with only half the number of chromosomes of the parent cell in each daughter cell. The process of meiosis can be separated into two cycles, the 1st division and the 2nd division. The first division consists of 4 phases. Prophase, Metaphase, Anaphase and Telophase. The Second division consists of prophase II, Metaphase II, Anaphase II and Telophase II. Interphase occurs at the beginning of each phase and Cytokinesis occurs at the end of each phase. Meiosis is used for the production of gametes, or sex cells, in sexually reproducing organisms. These daughter cells have only half the number of chromosomes of a normal body cell. This is important because when two gametes come together, the number of chromosomes in the zygote

In meiosis the pairs of chromosomes (that code for possible outcomes of characteristics) temporarily join and exchange information (crossing over) creating different combinations of gene types (alleles). For example; a pair of chromosomes could be a dominant allele (gene type) and a recessive allele which might code for brown hair. After crossing over it might be recessive which could be blond hair.