Biology - Anatomy signature assignment

General Instructions for Writing Lab Reports

Writing a lab report is a standard feature of science lab classes. Writing an organize lab report will help you understand the scientific method. A person should be able to read your lab report and:

· know exactly how to do this experiment

· find a table, graph or photo of your results

· know what you concluded at the end of your experiment

· know what experiment you would do next to follow up on these results

Scientific writing is somewhat different from writing for other disciplines. What are the major differences that you should look out for?

· The passive voice is used. So instead of writing, “I measured the bone with the meter stick,” it would be “The bone was measured with a meter stick”. The report is about the work, not about you.

· Keep the language simple and use your own words

· Avoid first or third-person pronouns: “I”, “We” and “They”

· Write in past tense in Methods, Results, and Conclusion.

· Use the present tense when you write your Introduction, and discuss implications in the Discussion Section.

· Sentences should be as short as possible, and only the most relevant information is included.

· Direct quotes are never used .

· Everything must be rewritten in your own words. Directly copying (or only slightly modifying) someone else’s work (including the work of other students and the material in the assignment handout/videos/resources) is plagiarism and will result in a grade of 0.

The format of a lab report is also different. These are the seven headings that you will use to write the lab report:

Statement of Purpose: The statement of purpose aims to answer the question: “What was the reason for this lab/experiment? What is hoped to be learned?” This section should consist of only one or two sentences.

Introduction: The introduction aims to review any background information pertaining to the lab/experiment. This is usually in the form of a paragraph with definitions, equations, and a summary of existing knowledge about the topic. The introduction requires outside references (not your assignment handout) which need to be cited in APA format.

At the end of the introduction, students should identify their dependent and independent variable along with their hypothesis. The independent and dependent variables may be either the antiserum or the reaction/lack of reaction between antiserum and blood type. The hypothesis should have the following format:

If (explain change in independent variable), then (explain change in dependent variable).

Materials: The materials section aims to provide a list of equipment and supplies used in the form of a bulleted list. Because this lab will be completed virtually, students must look up the materials needed to perform a blood typing test. This will include any instruments, technology, and other tools that are commonly used. A lot of this information can be found in the video and simulator linked on the student assignment handout.

Methods: The methods section aims to provide a detailed, step-by-step guide to performing the experiment in a paragraph form. Because this lab will be completed virtually, students must look up the procedure used to perform blood typing test. This section should describe how each item in the materials list was used. A lot of this information can be found in the video and simulator linked on the student assignment handout.

Results: The results section aims to: show the any measurements taken in the lab in a table, describe any uncertainties that may be derived from random or systematic errors, and provide graphs (with titles and labeled axes) when applicable. Graphs and tables should be given a number and title. Refer to graphs and tables using the number. For example, Table 1 shows …

Results section must include both Tables A and B from the assignment handout.

Discussion/Conclusions: The discussion/conclusions section aims to present findings from the lab/experiment and evaluate the accuracy and precision of the findings compared to the expected findings, This section should be the longest part of the lab report as it should explain what the findings from the tables in the “Results” section mean and what implications they may have on real-world examples such as pathologies, case studies, etc. In addition, make sure to answer any analysis questions mentioned in the lab assignment and also mention other questions you’d like to see answered and future extensions of the experiment that might be helpful in answering those questions.

References: The references section aims to provide citations for any outside information used in your lab report. References are usually found in the Introduction and the Discussion section of the lab report. Please make sure to paraphrase and not use direct quotes . After the paraphrased section, a parenthetical citation should be used to indicate where the information comes from. A full list of references should be listed at the end of the report. References should be completed in APA style.

Assembling Your Report

· Use the grading rubric as a cover page. Be sure the complete names of all group members and your class section are on the cover page.

· Type the report.

· Number the pages of the report

· Please staple the pages together. No folders or paper-clips will be accepted.

Sample Lab Report #2

Name: James Bond

Lab: Synthesizing Aspirin

Due date:

Purpose

The purpose of this experiment was to synthesize salicylic acid from methyl salicylate and sodium hydroxide (NaOH).

Introduction

Salicylic acid (1) is a compound found in willow bark extracts and has been used as a pain reliever and anti-inflammatory for thousands of years (D’Souza, 2017). However, the downside to using 1 is that it can cause gastrointestinal irritation (D’Souza, 2017). In addition to being found in plants, 1 is also synthesized from benzoic acid in the human body because of its properties as an anti-inflammatory compound (Feigenson, 2016) Furthermore, methyl salicytate (2) and acetyl salicylic acid (3) are metabolized to 2 in the body (D’Souza, 2017), Excessive amounts of these drugs can have an adverse affect on the body, sometimes leading to death (D’Souza, 2017).

3 is a compound derived from both 1 and 2. After many experiments, Felix Hoffman, a researcher for Bayer Company, found that 3 had similar pain-relieving side effects to 1 and 2 but without the irritation to the gastrointestinal tract (D’Souza, 2017). This was attributed to the conversion of the phenol group to an acetyl group (Feigenson, 2016).

A base-promoted hydrolysis of 1 and NaOH was completed in water, allowing the OH- nucleophile to attack the methyl ester. As a result, a disodium salt was formed and acidified to form a carboxylic acid group. This process is called saponification and results in the synthesis of 2 (D’Souza, 2017). In order to synthesize 3 from 2, an esterification reaction can be used to add an ester group in place of the phenol group (D’Souza, 2017).

Materials

· Methyl Salicylate (2.0 ml, 2.36 g, 15.5 mmol)

· 4 M NaOH solution (31 mL, 124 mmol)

· 6 M HCl (21 mL, 124 mmol)

· Hot Plate

· 1 400-ml beaker

Vacuum filtration

· 125 mL Erlenmeyer flask

· Magnetic stirrer

· Glass stirring rod

· Cold Water

· Ice bath

· Buchner funnel

· Filter Paper

Digital Melt-Temp Apparatus

· Vacuum filtrate flask

· Vacuum

· Weighing scale

· Capillary Tubes

· Digital Melting Point Apparatus

Methods

2 (2.0 mL, 2.36 g, 15.5 mmol, 1.0 equiv) was combined with 4 M NaOH solution (31 mL, 124 mmol, 2.0 equiv.) The cloudy and white mixture was heated to 300 C and stirred until it came to boil. The heat was turned down to 200 C and the reaction heated for an additional 15 min. The clear homogenous solution was cooled in an ice bath until it reached 15 C. 6 M HCl solution (21 mL, 124 mmol) was added to the flask. The solution became very cloudy and white precipitate was visible and the flask became very warm, indicating an exothermic reaction. The contents were stirred with a glass stirring rod and scratched to create white precipitate. The precipitated solid was collected through vacuum filtration and the crystals in the Buchner funnel were rinsed with cold water (2 mL). The filter flask with filtrate was emptied and air was pulled over the crystals for 2 min. The fine, white, powdered crystals were transferred to a 125 mL Erlenmeyer flask and combined with cold water (60 mL). The solution was heated to 200 C and stirred until it came to a boil and all solute particles had dissolved. The flask was taken off of the hot plate and set to cool on benchtop for 5 min. Thin, white, hair-like crystals formed on both the surface and bottom of the solution. Once 1 crystals started forming, the flask was placed in an ice bath for 3 min to complete recrystallization. The 1 crystals were collected through vacuum filtration and then had air pulled over them for 5 min.

After a week, the sample was placed into a capillary tube and inserted into the Digital Melting Point apparatus to determine the melting point range for the sample.

Results

The salicylic acid (1) crystals were weighed when wet at 1.824 g and a week later after they had dried (1.526 g). The mass of the dried crystals proved a 71.3% yield of 1. The melting point range of the crystals was determined to be 158.5-159.8 C.

Discussion

In the first step of the synthesis, formation of 2, a 71.3% yield was achieved, The melting point range of the synthesized 2 was 158.5-159.8 C. The literature melting point range is 158.8-161.0 C (D’Souza, 2017). Using percent error, this shows a .18% error in the solid crystals temperature change and a 0.74% error in the liquid temperature change. This proves that the synthesized 2 crystals contained very little impurities.

2 was synthesized through the base-promoted hydrolysis of 1 in water. Vacuum filtration and recrystallization techniques were used in both syntheses. In the vacuum filtrations, it was important to minimize the amount of cold water used to wash the crystals since they may dissolve in water and cause loss of product. Furthermore, after the initial vacuum filtration, it was important to empty the filtrate flask and pull air over the crystals to help remove any impurities that may have been trapped at the top. During recrystallization, instead of allowing the solution to recrystallize quickly in an ice bath, the solution was allowed to rest on bench top for five min and start to recrystallize slowly. Larger and purer crystals form when cooled slowly because of the increased time to form larger crystal lattice networks and allow impurities to be left behind in solution.

In the future, it would be interesting to synthesize Acetyl Salicylic Acid, the compound known as Aspirin. This could be done by completing an esterification reaction with salicylic acid and hydrolyzed acetic anhydride (Feigenson, 2016).

References:

D’Souza, L (2017). The Two-step synthesis of Aspirin. Organic Chemistry, 1st edition. 1-12.

Feigenson, L (2016). Synthesis of Salicylic Acid. Lecture Powerpoint. Slides 4-47.

Citation Examples

Here are some examples for how to reference and cite some common materials you may use in writing your lab report.

Books and Journals

The reference needs to include enough information to ensure a reader can find it quickly, easily, and specifically. If only part of a work is referenced (e.g. a chapter of a book) that should be noted.

Author name or names. (Year of publication). Title of article or chapter. Title of journal or book, Volume (issue), page numbers.

Brooker, Robert, Eric Widmaier, Linda Graham, and Peter Stiling. (2014). Simple Patterns of Inheritance. Biology 3rd Edition, 321-342.

Herbst-Damm, K.L., & Kulik, J.A. (2005). Volunteer support, marital status, and the survival times of terminally ill patients. Health Psychology, 24, 225-229.

In-text citations should use the format (author, year of publication).

Gregor Mendel made thousands of crosses of peas in his lifetime (Brooker, 2014).

People survive difficult times better when they have a support network (Herbst-Damm & Kulik, 2005).

Websites (List as much information as possible; you may need to hunt around the webpage to find all the information)

Author name or names. (Date of Publication). Title of webpage. Retrieved [date] from [web address]

Harris, William. (18 January 2001). "How DNA Evidence Works." Retrieved 6 January 2014 from http://science.howstuffworks.com/life/genetic/dna-evidence.htm

Half of a person’s DNA markers come from their mother and half from their father (Harris, 2001).

If there is no author given for a website, then the reference should begin with the name of the webpage, which should also be used in the citation:

“Apomixis.” (2 January 2014). Retrieved 6 January 2014 from http://en.wikipedia.org/wiki/Apomixis

Apomixis is the asexual reproduction of plants through seeds (Apomixis, 2014).

If there is no date of publication given for a website use the abbreviation n.d. The citation should also include this abbreviation.

Johnson, Tina. (n.d.). “Foods Rich with Enzymes.” Retrieved 6 January 2014 from http://www.mbspirit.net/uploads/Foods_Rich_with_Enzymes.pdf

Many of the foods we eat contain enzymes (Johnson, n.d.).

Social media sites such as YouTube can also be used as references. The screen name and, if possible real name, of the person posting the information should be used.

Author, A. A. [Screen name]. (Date of Publication). Title of video [Video file]. Retrieved [date] from [web address]

Andersen, Paul. [Bozeman Science]. (21 April 2012). Meiosis [video file]. Retrieved 6 January 2014 from http://www.youtube.com/watch?v=rB_8dTuh73c

7DrDon. (16 May 2011). Protein synthesis (DNA transcription, translation and folding) [video file]. Retrieved 6 January 2014 from http://www.youtube.com/watch?v=erOP76_qLWA

The female gamete is the egg and the male gamete is the sperm (Andersen, 2012).

Translation, or production of the protein, occurs at the ribosome (7DrDon, 2011).

How To Avoid Plagiarism

Plagiarism is claiming someone else’s words as your own and will results in a grade of 0 in this course. The purpose of writing a lab report is to demonstrate understanding of the material; copying-and-pasting someone else’s work indicates that this has not been achieved.

For example, a student wants to use the following information in the lab report:

A molecule or compound is made when two or more atoms form a chemical bond, linking them together. The two types of bonds are ionic bonds and covalent bonds. In an ionic bond, the atoms are bound together by the attraction between oppositely-charged ions. For example, sodium and chloride form an ionic bond, to make NaCl, or table salt. (Helmenstine, n.d.)

It would NOT be acceptable to quote any part of this information; direct quotes are not allowed in your lab report. It would also NOT be acceptable to only slightly modify the wording of this information. For example:

Molecules or compounds are formed when two or more atoms are linked in a chemical bond. Ionic bonds and covalent bonds are the two types of bonds. In ionic bonds, atoms are held together by attractions between oppositely-charged ions (Helmenstine, n.d.).

The sentences above are plagiarized and would earn this student a 0 on the lab report. They do NOT demonstrate understanding of the science that is being explained.

The simplest way to avoid plagiarism is to read the material, set it aside, and without looking at it write what you remember from what you read. This way the content or learning from the material will be in your own words. For example,

Chemicals are formed through two types of bonds, covalent bonds and ionic bonds. These bonds hold atoms together to make compounds and molecules. Ionic bonds are formed by attractions between positive and negative ions (Helmenstine, n.d.).

These sentences have the same information, but the writing style is quite different. The changes show that the student understands what is being written.

References:

Helmenstine, Anne Marie. (n.d.). “What Is the Difference Between an Ionic and Covalent Chemical Bond?” Retrieved 6 January 2014 from http://chemistry.about.com/od/chemistrystudentfaqs/f/bondtypes.htm .