Name: Student ID: General Biology Laboratory Exercise Laboratory Exercise 9:Mitosis & Meiosis1. The Cell Cycle. The cell cycle can be divided into two major phases: interphase and the mitotic phase. Interphase accounts for about 90% of the cycle, divided into three phases: G1, S, and G2 phases. a. Label the cell cycle diagram with these terms: interphase, G1, G2, S, mitosis, anaphase,metaphase, prophase, telophase, cytokinesis. Identify the key events take place during G1, G2, & S.2. Karyotype. At a computer, open the following internet link:http://www.biology.arizona.edu/cell_bio/tutorials/meiosis/main.htmlClick on “Chromosomes in a Diploid Cell”. Read the section on Karyotyping. Click on the word “Karyotype” to go to the next link. Go through the questions for this section. Scroll to the bottom of the screen and click on “Patient Histories”. Click on “Complete Patient A’s Karyotype”. Answer the questions below as you go through the exercise.a. What number of chromosome does the first homologous chromosome match? b. What number of chromosome does the second homologous chromosome match? Key event: Key event:Key event:c. What number of chromosome does the third homologous chromosome match? d. What number of chromosome does the fourth homologous chromosome match? e. What number of chromosomes does the extra chromosome match? f. What notation would you use to characterize Patient A’s karyotype? g. What diagnosis would you give to Patient A? 3. Mitosis Models. If you need visual models in order to learn then you may use the colored beads provided. You can model the stages of mitoses using colored beads if you feel this is necessary. However, you are not required to use these beads for the drawings. Try to make your drawing from your knowledge and memory and do not use your text book. Mitosis is artificially divided into four phases, but understand that mitotic divisions occur gradually, and the phases are not naturally distinct.a. Prophase. Prophase begins when chromosomes coil and condense. The centrioles (in animal cells) are visible as they move to opposite poles of the cell. Spindle fibers begin to form between the centrioles. i. What cellular material makes up the spindle fibers? ii. Describe the distribution of the chromosomes, which are now visible, during prophase. iii. Draw three pairs of duplicated chromosomes. Each chromosome should consist of a pair of identical chromatids, joined together at the centromere. Individual chromosomescan be different lengths, however sister chromatids must be the same length. Make the different pairs different sizes so you can identify between them. (Optional Beads: On your lab bench, simulate prophase with your six chromosomes.) Draw your results in the “cell” below.2iv. When did the chromosomes undergo duplication to create the sister chromatids? 3b. Metaphase. In metaphase, the chromosomes move to the “equator” of the cell (equatorial plate). The sister chromatids are still held together. i. Draw metaphase in the space below. Include the spindle apparatus in your drawings. (Optional Beads: Position your six chromosomes on your lab table, with the centromeres along the equatorial plate.) Draw your results below.c. Anaphase. The centromeres now begin to split, with the identical chromatids separating and moving to opposite poles.i. What is each of these chromatids now called? ii. Draw anaphase below. How does this cell elongate? ________________________ _____________________________________________________________________ (Optional Beads: With your beads, now separate the sister chromatids for each of your six chromosomes, pulling them in opposite directions, mimicking anaphase.) By separating the chromatids, each has now become a newly independent chromosome. Draw your results below.4d. Telophase. In this phase, the chromosomes have now reached the poles, the nuclear envelope begins to reform around each bundle of chromosomes, and the chromosomes become indistinct. In animal cells, a cleavage furrow begins to form at the equatorial plate, and pinches inward until two separate cells are formed. This final process is knownas cytokinesis, and overlaps with both anaphase and telophase.i. Draw telophase below for both plant and animal cells and describe how cytokinesis is accomplished in both plants and animals 54. Does each new cell formed by this process have the same or different chromosomal material as each other? Is the chromosomal material the same or different from the original cell? 5. Mitosis in Cells. Now we will study the stages of mitosis using prepared slides of animal cells and plant cells. The animal cells we will examine are from the blastula (developing embryo) of a whitefish. The plant cells we will examine are from an onion root tip. For eachstage of mitosis, draw a cell from the onion root tip (on the left) and a cell from the whitefish blastula (on the right) in the spaces below. When possible, label a chromosome, the spindle fibers, the poles, and the equatorial plate.a. Prophase.Onion root tip Whitefish blastulab. Metaphase.Onion root tip Whitefish blastulac. Anaphase.Onion root tip Whitefish blastula6d. Telophase.Onion root tip Whitefish blastulae. Interphase.Onion root tip Whitefish blastula76. Meiosis. In sexually reproducing organisms, the genetic material is combined in the offspring. If gametes contained two sets of chromosomes (diploid or 2n) as most cells do, the offspring would end up with twice as many chromosomes as the parents after fertilization! To avoid this problem, many organisms have cells that undergo meiosis to reduce the chromosome number in half in the gametes (haploid or n).a. What is the diploid number for humans? b. What is the haploid number for humans? c. To study meiosis, we will model the process using either drawings or colored bead chromosomes. Start with three of chromosomes. Duplicate these chromosomes. When would these chromosomes duplicate? ____________ Draw/make a large pair, a medium pair and a small pair of chromosomes. Use your colored pencils. Not Duplicated