Meiosis and Sexual Reproduction Lab Report.
Meiosis and Sexual Reproduction Lab Report.
BioLab3 Meiosis and Sexual Reproduction Lab Report Name, date, course and section required for password: The lab report is unique each semester and checks have been put into place to ensure students are doing their own work. Copying from other students or from outside resources will result in a zero on the accompanying lab quiz. I. Homologous Chromosomes 1. On a pair of homologous chromosomes, two alleles both code for blue eyes. Is this condition considered homozygous or heterozygous? 2. What does heterozygous mean? 3. What is the difference between diploid and haploid cells? 4.
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Based on Lab, Exercise 1, what do the letters F and B represent? II. Meiosis in Eukaryotes 1. At the end of meiosis II, are the resulting cells haploid or diploid? 2. Print the document found in Lab, Section 1. Use this document to follow along with Exercise 2 and draw the beads as they appear at the end of each stage of meiosis I and meiosis II. Sign and date your completed document and include with this lab report. III. Oogenesis and Spermatogenesis 1. What type of cells undergo meiosis? 2. Where does meiosis occur in human males and females? © 2016 Access Learning Systems SP22 1 3. After fertilization occurs, are the resulting cells diploid or haploid in chromosome number? IV. Summary of Mitosis and Meiosis 1.
Compare mitosis and meiosis in the table below. Mitosis Meiosis Number of chromosomes in resulting cells Number of nuclear divisions V. Meiosis and Life Cycle 1. How many total chromosomes do frogs have? 2. How many pairs of chromosomes do frogs have? 3. Determine whether the following types of cells are haploid (1n) or diploid (2n). Type of cell Haploid or Diploid Body cell Sperm cell Egg cell Zygote Summary Questions 1. Distinguish between meiosis and mitosis. 2. If a horse has 64 chromosomes before meiosis, how many chromosomes would exist in each nucleus after meiosis I? After meiosis II? © 2016 Access Learning Systems SP22 2 3. Is meiosis I or meiosis II most like mitosis? Explain why. 4. Name the male and female gametes that are produced by meiosis. 5. A trait is given the alleles aa. It this homozygous or heterozygous? 6. Before mitosis begins one sister chromatid of a duplicated chromosome has the allele f, what allele will the other sister chromatid have?
7. What would happen if gametes were produced by mitosis instead of meiosis? 8. Differentiate between homologous chromosomes and sister chromatids. © 2016 Access Learning Systems SP22 3 Lab 10 – Meiosis and Sexual Reproduction EXERCISE 1 Construction of homologous chromosomes 1. Select twenty-four pop beads of one color and two magnets. Construct two strands of pop beads consisting of five beads of one color on one side of the magnet and seven beads of same color on other side of the magnet. Each colored bead represents a gene segment. Each strand represents a chromosome. The two strands represent a replicated chromosome (Figure 2). 2. Place a piece of tape with the letter F on the two top beads of one set and a letter B on the two bottom beads. Join these identical sections at their magnets representing the sister chromatids of a replicated chromosome (Figure 2). The magnets represent the centromere of the replicated chromosome. 3. Select a second color of pop beads. Construct the homologue to the replicated chromosome above. Construct the same size structure as the one in steps 1 and 2. Place a letter f on the top two beads of this set and a letter b on the bottom two beads of the set. Join this set by their magnets. 4. You have constructed a model of two replicated chromosomes that are homologous to each other. They have two gene positions along their length labeled F, B, or f, b (Figure 2). sister chromatids sister chromatids Figure 2 Model of Replicated homologous chromosomes EXERCISE 2 Modeling the stages of meiosis with pop beads Meiosis I begins with a nucleus that is diploid. The chromosomes are in their replicated state. Meiosis I has four stages: Prophase I, Metaphase I, Anaphase I, and Telophase I. 1. Place the strands of pop beads constructed in Exercise 1 on the lab table and draw a chalk circle representing the cell nucleus around the two sets of pop beads. During interphase the chromosomes are replicated and consist of two identical parts termed sister chromatids. The replicated chromosomes are randomly dispersed throughout the nucleus. Draw the pop beads during Interphase (Figure 4). Be sure to include the letters which represent the alleles. 2. Prophase I During this stage the nuclear envelope disassociates and the replicated chromosomes become condensed. The spindle apparatus will begin to extend toward opposite poles. The spindle apparatus can be represented with pieces of string as the spindle fibers and two X’s as the centrosomes. Prophase I is unique because homologous chromosomes pair with each other and intertwine as a tetrad. This pairing process is called synapsis. Using the 2 strands of each color bead representing the homologous pair, illustrate synapsis. During synapsis the non-sister chromatids exchange genes at the F and f positions. When gene segments are exchanged between non-sister chromatids of homologous chromosome pairs, it is termed crossing-over (Figure 3). Remove one color bead with the F and exchange with the other color bead f. In late prophase, the homologous chromosome pairs begin to move to the spindle equator as a tetrad and the spindle fibers attach to the centromeres. Tie a length of string to each of the two homologues at the centromere region. Draw the pop beads during prophase I (Figure 4). Include the letters indicating the alleles of each sister chromatid. Figure 3 Model of gene exchange between homologous chromosomes 3. Metaphase I The centromeres of each homologue are situated on opposite sides of the equator and spindle fibers attach each one to opposite spindle poles. Position the loose ends of the strings that are attached to each homologue at opposite poles. Illustrate this step of meiosis I with the pop beads. Draw the pop beads during metaphase I (Figure 4). 4. Anaphase I During anaphase I, homologous chromosomes separate and are pulled to opposite poles by the shortening of the spindle fibers. Each homologue still contains two sister chromatids. Demonstrate this step by pulling the strings attached to each homologue in opposite directions toward a pole marked with an “X” on your lab table. Draw the pop beads during anaphase I (Figure 4). 5. Telophase I Each homologue is now at its respective pole and cytokinesis is completed. Demonstrate this by drawing a chalk circle around each of the two homologues, or replicated chromosomes, representing the two cells formed by cytokinesis. Draw the pop beads during telophase I (Figure 4). The first meiotic division is complete. There are two daughter cells each containing one replicated chromosome consisting of two sister chromatids.
The nucleus of each cell is now haploid. This is why meiosis is known as reduction division, reducing the number of chromosomes in the cells by half. Indicate the alleles on each of the chromatids in the 2 cells. Meiosis II occurs in each of the daughter cells that resulted from meiosis I which contain half the amount of chromosome material as the beginning cell nucleus. Meiosis II has four stages: Prophase II, Metaphase II, Anaphase II, and Telophase II. 6. Prophase II The sister chromatids are still attached by their centromeres. The spindle apparatus forms again and begins to migrate and spindle fibers attach to the centromeres. Draw the pop beads during Prophase II (Figure 4). Indicate the alleles on each of the chromatids. 7. Metaphase II The replicated chromosomes align along the equator, the centromeres lying on the equator. The spindle fibers attach each chromatid to opposite spindle poles. Draw the pop beads during metaphase II (Figure 4). Indicate the alleles on each of the chromatids. 8. Anaphase II The sister chromatids separate, moving toward the opposite poles. After the sister chromatids separate, each is an individual (not replicated) chromosome. Cytokinesis (cytoplasmic division) begins during anaphase II. Separate the two lengths of pop beads at the magnet and pull them toward opposite polls.
Change the chalk circle so that it dips inward in the center to illustrate cytokinesis. Draw the pop beads illustrating anaphase II (Figure 4). Indicate the alleles on each of the chromatids. 9. Telophase II The two chromosomes are at opposite poles. The nuclear envelope forms around each set and cytokinesis is completed forming four cells. Meiosis and Sexual Reproduction Lab Report.
Four daughter nuclei now exist. Each nucleus contains one individual chromosome of the homologous pair originally present within the parental nucleus. Illustrate telophase with the pop beads, and with the use of chalk, complete the nuclear membrane around the beads and the plasma membrane of the new cells formed by cytokinesis. Draw the result of telophase II (Figure 4). Indicate the alleles in each cell. Interphase (2n) MEIOSIS I Prophase I Metaphase I Anaphase I Telophase I (Continued) * * Figure 4 Stages of meiosis (Meiosis continued) * MEIOSIS II * Prophase II Metaphase II Anaphase II Telophase II Figure 4 Stages of meiosis (continued)\
You must proofread your paper. But do not strictly rely on your computer’s spell-checker and grammar-checker; failure to do so indicates a lack of effort on your part and you can expect your grade to suffer accordingly. Papers with numerous misspelled words and grammatical mistakes will be penalized. Read over your paper – in silence and then aloud – before handing it in and make corrections as necessary. Often it is advantageous to have a friend proofread your paper for obvious errors. Handwritten corrections are preferable to uncorrected mistakes.
Use a standard 10 to 12 point (10 to 12 characters per inch) typeface. Smaller or compressed type and papers with small margins or single-spacing are hard to read. It is better to let your essay run over the recommended number of pages than to try to compress it into fewer pages.
Likewise, large type, large margins, large indentations, triple-spacing, increased leading (space between lines), increased kerning (space between letters), and any other such attempts at “padding” to increase the length of a paper are unacceptable, wasteful of trees, and will not fool your professor.
The paper must be neatly formatted, double-spaced with a one-inch margin on the top, bottom, and sides of each page. When submitting hard copy, be sure to use white paper and print out using dark ink. If it is hard to read your essay, it will also be hard to follow your argument.
ADDITIONAL INSTRUCTIONS FOR THE CLASS
Discussion Questions (DQ)
Initial responses to the DQ should address all components of the questions asked, include a minimum of one scholarly source, and be at least 250 words.
Successful responses are substantive (i.e., add something new to the discussion, engage others in the discussion, well-developed idea) and include at least one scholarly source.
One or two sentence responses, simple statements of agreement or “good post,” and responses that are off-topic will not count as substantive. Substantive responses should be at least 150 words.
I encourage you to incorporate the readings from the week (as applicable) into your responses.
Weekly Participation
Your initial responses to the mandatory DQ do not count toward participation and are graded separately.
In addition to the DQ responses, you must post at least one reply to peers (or me) on three separate days, for a total of three replies.
Participation posts do not require a scholarly source/citation (unless you cite someone else’s work).
Part of your weekly participation includes viewing the weekly announcement and attesting to watching it in the comments. These announcements are made to ensure you understand everything that is due during the week.
APA Format and Writing Quality
Familiarize yourself with APA format and practice using it correctly. It is used for most writing assignments for your degree. Visit the Writing Center in the Student Success Center, under the Resources tab in LoudCloud for APA paper templates, citation examples, tips, etc. Points will be deducted for poor use of APA format or absence of APA format (if required).
Cite all sources of information! When in doubt, cite the source. Paraphrasing also requires a citation.
I highly recommend using the APA Publication Manual, 6th edition.
Use of Direct Quotes
I discourage overutilization of direct quotes in DQs and assignments at the Masters’ level and deduct points accordingly.
As Masters’ level students, it is important that you be able to critically analyze and interpret information from journal articles and other resources. Simply restating someone else’s words does not demonstrate an understanding of the content or critical analysis of the content.
It is best to paraphrase content and cite your source.
LopesWrite Policy
For assignments that need to be submitted to LopesWrite, please be sure you have received your report and Similarity Index (SI) percentage BEFORE you do a “final submit” to me.
Once you have received your report, please review it. This report will show you grammatical, punctuation, and spelling errors that can easily be fixed. Take the extra few minutes to review instead of getting counted off for these mistakes.
Review your similarities. Did you forget to cite something? Did you not paraphrase well enough? Is your paper made up of someone else’s thoughts more than your own?
Visit the Writing Center in the Student Success Center, under the Resources tab in LoudCloud for tips on improving your paper and SI score.
Late Policy
The university’s policy on late assignments is 10% penalty PER DAY LATE. This also applies to late DQ replies.
Please communicate with me if you anticipate having to submit an assignment late. I am happy to be flexible, with advance notice. We may be able to work out an extension based on extenuating circumstances.
If you do not communicate with me before submitting an assignment late, the GCU late policy will be in effect.
I do not accept assignments that are two or more weeks late unless we have worked out an extension.
As per policy, no assignments are accepted after the last day of class. Any assignment submitted after midnight on the last day of class will not be accepted for grading.
Communication
Communication is so very important. There are multiple ways to communicate with me:
Questions to Instructor Forum: This is a great place to ask course content or assignment questions. If you have a question, there is a good chance one of your peers does as well. This is a public forum for the class.
Individual Forum: This is a private forum to ask me questions or send me messages. This will be checked at least once every 24 hours. Meiosis and Sexual Reproduction Lab Report.
Meiosis and Sexual Reproduction Lab Report.