Ap Biology Lab Report 4 Essay Example

Ap Biology Lab Report 4 Paper Introduction 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 telophase. Meiosis is a two-part cell division process in organisms that sexually reproduce. Meiosis produces gametes with one half the number of chromosomes as the parent cell. There are two stages of meiosis: meiosis I and meiosis II. At the end of the meiotic process, four daughter cells are produced. Each of the resulting daughter cells has one half of the number of chromosomes as the parent cell. Mitosis was studied first in this lab. The phases of onion root tips were observed under a microscope. The crossing-over of chromosomes in meiosis was observed by viewing photos. Hypothesis If looking under a 400 power microscope, than it is possible to observe mitosis occurring in whitefish blastula and onion root tips. If crossing-over occurs in meiosis, than the genes do not segregate until meiosis II. Materials and Methods All materials and methods followed based off of lab manual. Results Activity A: Observing Mitosis Interphase Cells Plant Cell Animal Cell Prophase Cells We will write a custom essay sample on Ap Biology Lab Report 4 specifically for you for only $16.38 $13.9/page Order now We will write a custom essay sample on Ap Biology Lab Report 4 specifically for you FOR ONLY $16.38 $13.9/page Hire Writer We will write a custom essay sample on Ap Biology Lab Report 4 specifically for you FOR ONLY $16.38 $13.9/page Hire Writer The cellular organelles doubled in number, the DNA replicated, and protein synthesis occurred. The chromosomes are not visible and the DNA appears as uncoiled chromatin. Prophase Plant Cell Animal Cell The chromatin condensed and the chromosomes became visible. The nucleolus disappeared, and the spindle forms and attaches to the centromeres of the chromosomes. Early and late prophase can be seen. In late prophase, the chromatin has condensed into chromosomes, the nucleolus is gone, and the nuclear envelope has been removed. Metaphase Cells Plant Cell Animal Cell The nuclear membrane fragmentation is complete and the duplicated chromosomes lined up along the cells equator. Anaphase Cells Plant Cell Animal Cell Diploid sets of daughter chromosomes separated and were pushed and pulled toward opposite poles of the cell. This was accomplished by the polymerization and depolymerization of the microtubules that helped to form the mitotic spindle. Telophase Cells Plant Cell Animal Cell The nuclear membrane and nucleoli reformed, cytokinesis is almost done, and the chromosomes uncoiled to chromatin. Daughter Cells Plant Cell Animal Cell The daughter cells formed and constructed a new dividing cell wall between them. Each daughter cell received a copy of the genome of its parent’s cell. Analysis of Results, Activity A: Observing Mitosis 1. I can infer that the two cells came from the cell a long time ago because they have similar organelles. 2. Two ways that mitosis differs in the cells of animals and higher plants is in cytokinesis and right before prophase. In plant cells, there is a pre-prophase right before prophase takes place. . A) Nuclear envelope disappears in prophase; nuclear envelope reappears in telophase B) Mitotic spindle forms in prophase; mitotic spindle disappears in telophase C) Chromatin condenses into chromosomes in prophase; chromosomes unwind to form chromatin in telophase D) Centrosomes are at opposite ends of the cell in metaphase E) Nucleolus disappears in prophase 4. The three sub phases of interphase are the G1 phase, S phase, and the G2 phase. I n the G1 phase, cell synthesizes proteins and produces cytoplasmic organelles. In the S phase, DNA synthesis occurs, and in the G2 phase, the cell beings forming the spindle. 5. Both prokaryotic cell division and eukaryotic cell division replicate their DNA and use the process of cytokinesis. Activity B: Estimating the Relative Lengths of Mitotic Phases Table 1: Group Count | Number of Cells| | Field 1| Field 2| Field 3| Total 1-3| Interphase| 52| 46| 57| 155| Prophase| 22| 25| 29| 76| Metaphase| 16| 11| 9| 36| Anaphase| 5| 8| 5| 18| Telophase| 14| 10| 8| 32| | Total| 317| Table 2: Class Data Class Totals| Decimal Fraction of Total Count| Estimated Time Spent in Phase| Interphase| 582| . 46| 13968| Prophase| 305| . 24| 7320| Metaphase| 148| . 12| 3552| Anaphase| 65| . 05| 1560| Telophase| 171| . 13| 4104| Total Cells Counted| 1271| | Analysis of Results, Activity B: Estimating the Relative Lengths of Mitotic Phases Pie Graph 2. Stages of Mitosis Ranked 1) Interphase 2) Prophase 3) Metaphase 4) Anaphase 5) Telophase 3. Some phases of mitosis are longer than othe rs because each phase has a different task, and some of the tasks of the phases are harder than others. For example, interphase takes longer than other phases because the nuclear envelope fragments and the microtubules attach to the chromosomes. Telophase takes the least amount of time because chromosomes only go to opposite ends of the cell and a nuclear membrane forms. Activity C: Simulating Meiosis Analysis of Results, Activity C: Simulating Meiosis 1. Sixteen combinations of the two chromosomes are possible. 2. Number of chromosome combinations= 3. There are possible combinations of chromosomes for human gametes. 4. There are possible combinations of chromosomes for the offspring. 5. The relationship of meiosis to variation in populations is that genes are able to move themselves and combine with different sets of genes that aren’t present in the parent. This causes a higher chance of survival. 6. Three ways that meiosis differs from mitosis are that meiosis occurs in reproductive cells, while mitosis occurs in somatic cells. In meiosis, a mitotic mother cell is always diploid, while in mitosis a mother cell can be haploid or diploid. In meiosis, two divisions of the mother cell causes four meiotic cells, while in mitosis, a single division of the mother cell causes two daughter cells. Activity D: Crossing-Over and Map Units Analysis Results, Activity D: Crossing-Over and Map Units Table 3 | No. of MI Asci (4:4)| No. of MII Asci (2:4:2 or 2:2:2:2)| Total Asci| %MII Asci (No. of MII/Total)| Gene-to Centromere Distance (%MI/2)| Group Data| 45| 65| 110| 59%| 29. 5 (30)| 1. Crossing-over increases genetic variation because when the chromatids exchange sections with each other, they get new combinations of alleles that their parents had, which causes more chromatids. . I would expect to find more genetic variation in the population of species B because it’s undergoing sexual reproduction. In sexual reproduction there is more changeability because the new generation has many combinations of the genes of the two parent organisms. 3. I would conclude that there was no occurrence of recombination since the MI Asci w ould be a 4:4 ratio. Discussion My results proved my hypothesis. This is so because by looking through the microscope it was possible to view the stages of mitosis in the onion root tip and the whitefish blastula. The stages of mitosis that were visible were prophase, anaphase, telophase, interphase, and metaphase. The time spent in each phase was also figured out. Interphase was the phase that the cell spends most of its life in. Telophase was the shortest phase. We stimulated the stages of meiosis using red and yellow magnetic beads. Crossing-over in Sordaria was observed by looking at photos. Afterwards, the map units were determined. We discovered that the distance of the gene relative to the centromere in the Sordaria was fifty-nine map units.

Free Essays on The Tragic Accident

came out. The next thing I knew we were on our way to the hospital in silence. Different thoughts were running over and over in my head. At that time I wished I my head would explode so I did not have to think anymore. For living only two blocks from the hospital it seemed like it took and eternity to get there. Finally we were at the hospital. The ambulance was parked in the emergency circle. Dying inside with horrific thoughts, I tried to gasp for air as I saw them bring in the emergency helicopter. After a sudden breeze I rushed inside with my sister. Chris, one of my younger sisters, was lying on the emergency bed with tears rolling down her eyes. She was strapped in like a wild animal that could not be controlled. She had two broken ribs; her collarbone was also broken. Since she had been unconscious they wanted her to lie there until further notice. I could not take looking at her cuts and the scratches anymore. I stood in the hall thinking to myself â€Å"What should I do† So I tried to get a hold of my mom for the hundredth time. Then all of sudden my dad and my grandparents... Free Essays on The Tragic Accident Free Essays on The Tragic Accident The Tragic Accident December 15, 2002 was the most terrifying day that I had ever been through. You don’t realize how much your family means to until something tragic happens to them. While sitting in my driveway listening to the sound of the frightful ambulance, something told me not to follow it. I sat in my car and started to think about different things like life, my family, and friends. Then I decided to turn my car off and go inside. My sister and nephew were at the door waiting to greet me. They were watching my younger brother while my mom took a night out. Ten minutes into our conversation the phone rang. Trin, my older sister answered it very quickly. While talking she turned towards me with a very pale look in her eyes and all of a sudden her mouth dropped, no words came out. The next thing I knew we were on our way to the hospital in silence. Different thoughts were running over and over in my head. At that time I wished I my head would explode so I did not have to think anymore. For living only two blocks from the hospital it seemed like it took and eternity to get there. Finally we were at the hospital. The ambulance was parked in the emergency circle. Dying inside with horrific thoughts, I tried to gasp for air as I saw them bring in the emergency helicopter. After a sudden breeze I rushed inside with my sister. Chris, one of my younger sisters, was lying on the emergency bed with tears rolling down her eyes. She was strapped in like a wild animal that could not be controlled. She had two broken ribs; her collarbone was also broken. Since she had been unconscious they wanted her to lie there until further notice. I could not take looking at her cuts and the scratches anymore. I stood in the hall thinking to myself â€Å"What should I do† So I tried to get a hold of my mom for the hundredth time. Then all of sudden my dad and my grandparents...

Crafting and Executing Strategy Assignment Example | Topics and Well Written Essays - 1000 words

Crafting and Executing Strategy - Assignment Example † And in this way, questions are answered for each stage. Strategic plan involves the mixture of vision, mission and out of the box thinking. Strategic planning is one of the major management tools managers have to be perfect at. It can offer many benefits for the business, like communicating the main set objectives and plans to the staff, developing a competitive advantage against the rival firms, providing a sense of direction and purpose and communicating the plan of action etc. Without the strategic plan, there will be no direction for the business and this could lead to the business being lost (Olsen, Tse & West 1998). Financial performance could also deter without these plans A mission statement is a precise statement of the business’ core targets and cynosure, framed in such a way to persuade and trigger interest by outside groups and the other stakeholders. The Mission Statement of the hotel that I am the manager with is â€Å"To provide exquisite hospitableness and cordiality to our priceless guests by delivering the finest personal and intuitive services to them.† These statements are not linked to a particular goal, but try to sum up – it describes the aims in an influential and an appealing way. Mission statements can prove to be essential for firms of all sizes. They quickly inform the stakeholders of the business of the main aim and vision are. They can also prove to ignite a spark to the employees and tell the outside groups that the business and its staff have these positive traits. They establish in the view of other stakeholders ‘what the firm is about’ and hence can provide public relations and increase the chances of success for them. While Vision statements are those statements of what the firm would want to acquire and achieve in the long-run. There are some distinctions between the vision and the mission statements. Mission statements are the synopsis of the whole of the purpose of the organization, while a vision statement, on the contrary, tells the picture of the ‘desired future’ and how the business will look if it is successful in accomplishing its mission. The vision statement of my hotel is â€Å"We will be recognized by our superior hospitality services, selectively franchising and flawless management. Introducing newness in our every assistance will also provide the platform for our goodwill.† There is a simple link between the concepts of vision statement, mission statement and strategic planning. Without the focal point brought by the vision and mission statements, planning new strategies and stance in order to give direction to the company will not be helpful as there is no central idea and the business could get lost in heading to the goals. These statements can prevent the firm from drifting away from the ambitions of the organization. It is really critical that both vision and mission statement are not ‘artistry of words’ so that they impress the people or customers, but also they are relevant to the business, understood by the staff and then are evolved into important strategic actions. Operational objectives