DNA Extraction Date Developed/Last Revised
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1. CREATE Follow your plan Modify as necessary to make it work Explain any modifications here IMPROVE Analyze data Repeat the engineering design process to optimize the product Genetics Fun Facts It takes about eight hours for one of your cells to completely copy its DNA The human DNA code is made up of about three thousand million A T C and Gs on each side of the DNA strand o If you were to start reciting the order of the ATCGs in your DNA tomorrow morning at a rate of 100 each minute 57 years would pass before you reached the end provided that you did not stop to eat drink sleep use the bathroom etc o If you were to stretch out the DNA from those 46 chromosomes in one cell and lay it end to end it would be over 2 yards in length o If the total DNA in one person were laid in a straight line it would stretch to the sun and back over 30 times it s 93 million miles from here to the sun You could fit one thousand nuclei across the period at the end of this sentence You could fit one million threads of DNA across the period at the end of this sentence o If the genome was a book it would be the equivalent of 800 dictionaries It would take a person typing 60 words per minute eight hours a day around 50 years to type the human genome You would need 3 gigabytes of storage space on a computer to hold all of this Yet all this information is contained inside the microscopic nucleus of a cell so tiny that it cou2. Engineering e CTE 7 1 1 Apply the design process through a set of methodical steps for turning ideas into useful and ethical products and systems e CTE 7 1 2 Assess a product or solution for possible modifications Page 1 Template last revised 8 28 12 Math CCSS Mathematics e 7 EE 3 Solve real life and mathematical problems using numerical and algebraic expressions and equations Literacy CCSS 7 WHST 7 2 Write informative explanatory texts to examine a topic and convey ideas concepts and information through the selection organization and analysis of relevant content e Introduce a topic clearly previewing what is to follow organize ideas concepts and information using strategies such as English Language definition classification comparison contrast and cause effect include formatting e g headings graphics e g charts Arts and Literacy tables and multimedia when useful to aiding comprehension e Develop the topic with relevant facts definitions concrete details quotations or other information and examples e Use appropriate transitions to create cohesion and clarify the relationships among ideas and concepts e Use precise language and domain specific vocabulary to inform about or explain the topic e Establish and maintain a formal style e Provide a concluding statement or section that follows from and supports the information or explanation presented Indicator 3 3 Generates new and
3. Unit Title DNA Extraction Grade Level 7 Date Developed Last Revised March 4 2013 Time Frame 60 270 minutes Unit Author s Jeanine Nakakura Leslie Hamasaki Primary Content Area Life Science Biology UNIT DESCRIPTION Students will extract DNA from strawberries As an extension students can extract DNA from other foods or their cheek cells and develop a DNA Extraction kit Big Ideas Student Insights that Will Be Developed Over the Course of the Unit e All living organisms from bacteria to plants animals and humans contain DNA e Genes and chromosomes determine the expressions of inherited traits e DNA is stored in a cell s nucleus and can be extracted using a few simple steps Essential Questions Questions that Will Prompt Students to Connect to the Big Ideas e Why is DNA so important in biology e How can predict what traits will be passed from one generation to another e How are genes and chromosomes important in determining heredity traits BENCHMARKS STANDARDS LEARNING GOALS Science HCPS III Science e SC 7 1 1 Design and safely conduct a scientific investigation to answer a question or test a hypothesis e SC 7 5 2 Describe how an inherited trait can be determined by one or more genes which are found on chromosomes CTE HCPS III Technology EET e Standard 1 TECHNOLOGICAL DESIGN Design modify and apply technology to effectively and efficiently solve problems CTE HCPS III
4. DNA Extraction Lesson 1 Lesson Title Strawberry DNA Extraction Grade Level 7 Date Developed Last Revised 03 4 13 Primary Content Area Life Science Biology Unit Author s eanine Nakakura Leslie Hamasaki Time Frame 50 minutes PLANNING Steps 1 2 amp 3 1 Standards Benchmarks and Process Skills Assessed in this Lesson Science HCPS III e SC 7 1 1 Design and safely conduct a scientific investigation to answer a question or test a hypothesis e SC 7 5 2 Describe how an inherited trait can be determined by one or more genes which are found on chromosomes Math CCSS e 7 EE 3 Solve real life and mathematical problems using numerical and algebraic expressions and equations 2A Criteria What Students Should Know and Be Able to Do Students can e Pre teaching Students should have basic knowledge of DNA structure and its location in organisms video lecture readings research e Safely conduct a scientific investigation to answer the question Is there DNA in strawberries e Observe first hand that DNA is in the food that they eat e Experience a simple method of DNA extraction and be able to explain the rationale of each step e Explain why DNA extraction is important to scientists 2B Assessment Tools Evidence Formative e Conversations o Bell ringer questions to begin class students will be shown 5 objects or shown a list and determine whether each contains DNA Examples of items to use apple rock n
5. Preparations Before Class 1 Cut string into 2 5 ft pieces These teacher preparation notes the related student handout and other activities for teaching biology are available at http serendip brynmawr edu sci_edu waldron 2 Setup a bucket of ice to keep alcohol cold or put alcohol in the freezer refrigerator until needed 3 Pour a small cup sports drink for each student During class 1 Distribute cups of sports drink to each student It is important for each student to swish the drink in his or her mouth vigorously for at least a minute in order to obtain enough cheek cells 2 Distribute a test tube rack with one test tube per student to each group Distribute one glove to each student Pass out the soap and meat tenderizer Alternatively you can have a station somewhere in the classroom where the students can access the soap etc 3 After at least 10 minutes when the students have completed the DNA structure portion of the student handout pass out the cold alcohol and pipettes 4 After 10 minutes when the students have completed the DNA replication portion of the student handout distribute one microcentrifuge tube and piece of string to each student 5 Assist students transfer of their DNA to their microcentrifuge tubes using the pipettes It helps to twirl the DNA around the end of the pipette to get a large wad together before sucking the DNA into the pipette Warn the students to be gentle while
6. amino acid sequence in a protein translation gt structure and function of the protein e g normal hemoglobin vs sickle cell hemoglobin gt person s characteristics or traits e g normal health vs sickle cell anemia Our DNA activity teaches students about DNA structure and replication but includes only minimal discussion of the function of DNA We recommend that you follow this DNA activity with our activity From Gene to Protein Transcription and Translation to teach students about the function of DNA This hands on simulation activity available at http serendip brynmawr edu sci_edu waldron trans helps students understand how the sequence of nucleotides in a gene specifies the sequence of amino acids in a protein which in turn determines the structure and function of the protein and results in characteristics such as sickle cell anemia One important point that is not mentioned in our Student Handout is that during actual DNA replication sometimes mistakes are made and the wrong nucleotide is added to the new strand of DNA DNA polymerase can proofread each new double helix DNA strand for mistakes and backtrack to fix any mistakes it finds To fix a mistake DNA polymerase removes the incorrectly paired nucleotide and replaces it with the correct one If a mistake is made and not found the mistake can become permanent Then any daughter cells will have this same change in the DNA molecule These changes are call
7. cells containing your DNA by swishing a liquid around in your mouth To extract DNA from your cells you will need to separate the DNA from the other types of biological molecules in your cells You will be using the same basic steps that biologists use when they extract DNA e g to clone DNA or to make a DNA fingerprint You will follow these 3 easy steps to extract the DNA Detergent eNzymes meat tenderizer Alcohol Purpose To extract DNA from your cheek cells to create a necklace to wear Materials Sports drink like Gatorade 10 mL per student Liquid dish soap 0 25 mL per student Meat tenderizer a pinch per student 70 95 isopropyl or ethyl alcohol 4 mL per student String for necklace 2 5 ft per student 3 oz Dixie cups 1 per student Tub of ice freezer or refrigerator 1 Tub for dirty test tubes 1 Bleach 1 bleach solution to sterilize test tubes Small test tubes tubes need to hold a minimum of 15 mL 1 per student Test tube rack 1 per group 0 5 1 5 mL fliptop microcentrifuge tubes 1 per student Transfer pipettes or straws 1 per group Gloves 1 per student Student Instructions Getting Your Sample of Cells Obtain a cup with sports drink You will need to get thousands of your cheek cells in the sports drink in order to extract enough DNA to see Therefore you should swish the sports drink around in your mouth vigorously for at least one minute Then spit the drink back into the cup
8. pipetting so they do not damage the fragile strands of DNA Inexperienced pipetters have a tendency to blow air into the liquid and suck up and expel the DNA several times in the test tube before transferring it to the microcentrifuge tube this tends to break the DNA strands 6 Put ona pair of gloves and collect the test tube racks from the students Pour test tube contents out down the sink rinse the test tubes and place them in a tub of 1 bleach solution for 10 minutes to sterilize them for the next class You may want to assign this job to a student 7 Remove test tubes from bleach water and invert them in the racks to dry for the next class 8 Return the alcohol to the ice bucket or freezer refrigerator Instructional Suggestions and Additional Information As background for this activity students should know that DNA is the genetic material and DNA is contained in chromosomes inside the nucleus inside a cell Understanding the Functions of Proteins and DNA available at http serendip brynmawr edu exchange bioactivities proteins provides a suggested sequence of activities for introducing students to DNA as the genetic material The proteases in the meat tenderizer not only digest histones the proteins that DNA wraps around but also break down enzymes in cells which could digest the DNA Cold alcohol helps to precipitate the DNA molecules by reducing the temperature and dehydrating the salty soapy solution of DNA immediately
9. to use the kit The kit should also discuss the purpose of each material and emphasize safety procedures Keep documentation of how you improved the original protocol to extract cheek cell DNA and the price you will charge for this kit to make a 25 profit You must also keep an engineering design process notebook with the following steps Ask Imagine Plan Create Experiment Improve
10. Step 1 Detergent Add a small amount of detergent to a test tube about 0 25 mL Put a glove on the hand you will use to hold your test tube not the hand you will use to pour Now carefully pour the drink containing your cheek cells into the test tube with detergent until the tube is half full Why am I adding detergent To get the DNA out of your cheek cells you need to break open both the cell membranes and the nuclear membranes Cell membranes and nuclear membranes consist primarily of lipids Dishwashing detergent like all soaps breaks up clumps of lipids This is why you use detergents to remove fats which are lipids from dirty dishes Adding the detergent to you cheek cell solution will break open the cell membranes and nuclear membranes and release your DNA into the solution Step 2 Enzymes Add a pinch of enzyme meat tenderizer to your test tube With your gloved thumb or palm covering the top of the test tube gently invert the tube five times to mix Remove your glove and throw it in the garbage Let the mixture sit for at least 10 minutes Why am I adding enzymes The nucleus of each of your cells contains multiple long strands of DNA with all the instructions to make your entire body If you stretched out the DNA found in one of your cells it would be 2 3 meters long To fit all of this DNA inside a tiny cell nucleus the DNA is wrapped tightly around proteins The enzyme in meat tenderizer is a protease which is an enz
11. creative ideas and approaches to developing solutions STEM Indicator 5 The ability to communicate effectively Competencies Page 2 Template last revised 8 28 12 LESSON SEQUENCE Learning Goals Lesson Title Description What Students Will Know and Be Able to Do Assessments Time Frame 1 Strawberry DNA Extraction Perform a simple DNA extraction from a fruit using Worksheet or Lab Report 60 minutes household materials Group discussion Understand that all living organisms contain DNA Describe the size structure and components of DNA Understand the importance of DNA 2 Cheek Cell Extraction Extract DNA from human cheek cells using household Worksheet or Lab Report 60 minutes extension materials could use Edmodo Collect and preserve DNA 3 DNA Extraction Kit Use the Engineering Design Process to design a kit to Report on current kits sold 150 minutes extension extract DNA using household materials Research similar kits and report on what is currently being sold and how students can make their kits more user friendly and cost efficient Calculate cost of kit to make a profit and put data into a report Write an instruction guide to explain how to use kit Create a 1 minute commercial or magazine advertisement to sell kit cost report instruction guide commercial or advertisement Page 3 Template last revised 8 28 12 STEM Lesson Seven Step Implementation Model Unit Title
12. e Have students extract DNA from other foods or cheek cell DNA o Cheek Cell DNA Extraction Protocol using Engineering Journal Teacher Prep Notes Student handout and Journal attached o Goto www livebinders com and search for Cheek Cell DNA for resources or go to Page 3 of 4 Template last revised 8 30 12 STEM Lesson Seven Step Implementation Model http www livebinders com play play id 323235 TEACHING amp ASSESSMENT Steps 4 5 6 amp 7 Completed by teacher after instruction has taken place 4 Teaching and Collecting of Evidence of Student Learning Teacher Notes 5 Analysis of Student Products Performances Formative Teacher Notes 6 Evaluation of Student Products Performances Summative Not necessary for every lesson Teacher Notes 7 Teacher Reflection Replanning Reteaching Next Steps Teacher Notes Page 40f 4 Template last revised 8 30 12 Science Ly s Behind Food K fi i Strawberry DNA Extraction Lesson Plan This lesson plan is for the extraction of DNA from strawberries Strawberries are an exceptional fruit to use for this lesson because each individual student is able to complete the process by themselves and strawberries yield more DNA than any other fruit i e banana kiwi etc Strawberries are octoploid meaning that they have eight copies of each type of chromosome Primary Learning Outcomes Students will observe first hand that DNA is
13. eavy duty Ziploc bag e 1strawberry per group of students e DNA extraction buffer solution 900 ml water 50 ml dishwashing detergent 2 teaspoons salt e small plastic cup to hold DNA extraction buffer solution e cheesecloth or coffee filters approximately 10 cm x 10 cm e small funnel e 50 ml vial test tube e glass rod or bamboo BBQ skewer wooden chopstick e cold ethanol or isopropyl alcohol e ice e LiveBinder Go to www livebinders com and search for DNA Extraction to find Livebinder with resources on DNA extraction You may also find the DNA extraction LiveBinder by using this link http www livebinders com play play id 249122 Handouts Other Resources please attach copies e Pre Post Test choose one online from DNA Extraction LiveBinder e Lab Handout Worksheet for Strawberry DNA Extraction attached is an example from The Science Behind Our Food Content Background for instructor All living organisms contain DNA Some fruits are especially suited for DNA extractions due to their multiple sets of chromosomes Strawberries are octoploid which means they have 8 copies of each chromosome human body cells are diploid they contain two copies of each chromosome Page 2 of 4 Template last revised 8 30 12 STEM Lesson Seven Step Implementation Model DNA extraction is a fairly simple procedure that requires a few steps e The lysis buffer detergent breaks open the cells by destroying the fatty membranes
14. ed and it seems to work best if the alcohol is cold Alternatively you can use the directions for extracting DNA from bananas available at http www2 le ac uk departments genetics vgec search for Go Bananas or wheat germ available at http learn genetics utah edu archive wheatgerm index html Any of these extraction procedures can be used together with our discussion worksheet activity about DNA structure and replication available at http serendip brynmawr edu exchange bioactivities DNA Frequently Asked Questions including answers to questions about Trouble shooting Understanding the Science Behind the Protocol Comparing the DNA Extracted from Different Cell Types and Real life Applications of the Science of DNA Extraction are available at http learn genetics utah edu content labs extraction howto faq html Helpful figures for explaining how detergents break down lipids are available at http learn genetics utah edu archive wheatgerm background html A DNA Extraction Virtual Lab is available at http learn genetics utah edu units activities extraction To help students understand why accurate replication of the sequence of nucleotides in DNA is so important you may want to use all or part of the following diagram in your discussion of question 3 on the top of page 5 of the Student Handout nucleotide sequence in the DNA of a gene gt nucleotide sequence in messenger RNA mRNA transcription gt
15. ed point mutations because they change the genetic code at one point i e one nucleotide Some point mutations result in significant effects such as the genetic disease sickle cell anemia To ensure student understanding of the basic process of DNA replication this activity ignores many of the complexities observed in actual DNA replication Also although the same basic DNA double helix structure is observed in all living organisms as emphasized in this activity the structure of chromosomes differs between eukaryotes and prokaryotes For more information on these topics see a college textbook for biology majors such as Campbell Reece et al Biology Freeman Biological Science or Raven et al Biology Extracting DNA From Your Cells Adapted from Hands on Activities for Teaching Biology to High School or Middle School Students Molecular Biology DNA Drs Ingrid Waldron and Jennifer Doherty http serendip brynmawr edu sci_edu waldron dna Today you will extract DNA from some of your cells and learn more about DNA Essential questions Why is DNA so important in biology What is the function of DNA Bellwork Put the correct answer to the pretest question here using pictures to explain the terms from big to small Go to Cheek Cell DNA LiveBinder at www livebinders com for Powerpoint to accompany lesson Background Information Cells from the lining of your mouth come loose easily so you will be able to collect
16. ewspaper a plastic pen rubber band paper clip Discuss answers in small groups then share out to class Responses to questions will give teacher an indication of students preconceptions All living things contain DNA o Optional Genetics Fun Facts info sheet attached Can turn into a True False Quiz or assign one fact to each student or group and have them create a poster to display in class o During lab ask students to explain what they are doing to check understanding of the purpose of each step Page 1 of 4 Template last revised 8 30 12 STEM Lesson Seven Step Implementation Model Observations e Pre assessment quiz online see LiveBinder http www livebinders com play play id 249122 for assessment to select choose one you like e Check to see if students are following lab directions and performing steps safely e Verbal and or written feedback on worksheet answers Summative please attach copies of rubrics and or other assessment tools e Product DNA extracted from strawberry have students photograph e Worksheet completed with accurate answers have students re do if not accurate e Post assessment quiz same as pre assessment 3 Learning Experiences Lesson Plan Start with the basic DNA extraction with strawberries Then use the same procedure with another fruit food OR do the Cheek Cell DNA Extraction as an extension to incorporate Math Engineering and Technology Materials e H
17. hwashing detergent or 100mL shampoo and finally 2 teaspoons salt Slowly invert the bottle to mix the extraction buffer Science Fs Lo Behind Food ev it Step 2 Duration 40 minutes to 60 minutes depending on class cooperation Lab procedures should be conducted as stated in the DNA Extraction Strawberry lab at the end of this document Modifications can be made based on the needs of the students Some classes may decide for each student to add individual components of the extraction buffer to the Ziploc bag roughly 2 tsp water 1 tsp soap 1 pinch salt while other classes may choose to use the teacher prepared extraction buffer from Step 1 When the students add ethanol to their strawberry extract they will see the fine white strands of DNA precipitate The DNA will form cotton like fibers that will spool onto the stirring rod inoculating loop popsicle stick Materials and Equipment For each student heavy duty ziploc bag freezer or storage bag 1 strawberry DNA extraction buffer 900mL water 50mL dishwashing detergent 2 teaspoons salt small plastic cup to hold extraction buffer cheesecloth to fit in small funnel 4 X 4 should be appropriate small funnel 50mL vial test tube glass rod inoculating loop or popsicle stick cold ethanol ice Total Duration 10 minutes teacher prep before class 40 60 minutes in class Assessment Lab report and or discussion questions Discuss questions as a class to assess the st
18. in the food that they eat Students will learn the simple method to extract DNA and why each step is necessary due to the complex organization of DNA in cells Students will learn why it is important for scientist to extract DNA from organisms Assessed Georgia Performance Standards SCSh2 Students will use standard safety practices for all classroom laboratory and field investigations SCSh4 Students use tools and instruments for observing measuring and manipulating scientific equipment and materials SB1 Students will analyze the nature of the relationships between structures and functions in living cells SB2 Students will analyze how biological traits are passed on to successive generations Background Strawberries are soft and easy to pulverize Strawberries have large genomes they are octoploid which means they have eight of each type of chromosome in each cell Thus strawberries are an exceptional fruit to use in DNA extraction labs The soap helps to dissolve the phospholipid bilayers of the cell membrane and organelles The salt is used to break up protein chains that bind around the nucleic acids DNA is not soluble in ethanol The colder the ethanol the less soluble the DNA will be in it Thus make sure to keep the ethanol in the freezer or on ice Procedures A tivities Step 1 Duration 10 minutes Teacher may choose prior to class to prepare the DNA extraction buffer In a container add 900mL water then 50mL dis
19. ld easily fit on the head of a pin Organism of genes Organism of chromosomes Yeast 6 000 Human 46 Drosophila 13 000 Gorilla 48 Nematode 18 000 Dog 78 Flowering plant 26 000 Dove 16 Human 30 000 Butterflies 380 I Bananas 66 Humans are 99 9 genetically identical only 0 1 of our genetic make up differs Our genes are remarkably similar to those of other life forms For example we share 98 of our genes with chimpanzees 90 with mice 85 with zebra fish 21 with worms and 7 with a simple bacterium such as E coli o Less than 2 of the total DNA carries instructions to make proteins The rest is misleadingly called junk DNA because it is a hodge podge of sequences that does not seem to code for anything Sources www genomecanada ca en info dna know aspx seplessons ucsf edu files Genetics 20Fun 20Facts doc Name Date Period If Were a Genetic Engineer would combine the DNA of Name of 1 organism Name of 2nd organism Drawing of first organism Drawing of second organism Drawing of genetically engineered organism Describe your organism on the back of this paper Describe your genetically engineered organism with a minimum of 5 sentences number your sentences from 1 to 5 Make sure you answer the questions in the checklist below to receive full credit for this assignment Answer the questions below comple
20. organisms e DNA replication produces two new DNA molecules that are identical to the original DNA molecule so each of the new DNA molecules carries the same genetic information as the original DNA molecule e During DNA replication the two strands of the original DNA double helix are separated and each old strand is used as a template to form a new DNA strand The enzyme DNA polymerase adds nucleotides one at a time using the base pairing rules to match each nucleotide in the old DNA strand with a complementary nucleotide in the new DNA strand Thus each new DNA double helix contains one strand from the original DNA molecule together with a newly synthesized matching DNA strand e In eukaryotic cells each chromosome consists of DNA wrapped around proteins The chromosomes are contained in the nucleus inside a nuclear membrane Equipment and Supplies Sports Drink like Gatorade 10 mL per student Liquid dish soap 0 25 mL per student Meat Tenderizer a pinch per student 70 95 isopropyl or ethyl alcohol 4 mL per student String for necklace 2 5 ft per student 3 oz Dixie cups 1 per student Tub of ice freezer or refrigerator 1 Tub for dirty test tubes 1 Bleach 1 bleach solution to sterilize test tubes Small test tubes tubes need to hold a minimum of 15 mL 1 per student Test tube rack 1 per group 0 5 1 5 mL fliptop microcentrifuge tubes 1 per student Transfer pipettes 1 per group Gloves 1 per student
21. rry in a Ziploc bag Funnel 2 Smash grind up the strawberry using your fist and fingers for 2 minutes Careful not to break the bag 3 Add the provided 10mL of extraction buffer salt and soap solution to the bag Test Tube 4 Kneed mush the strawberry in the bag again for 1 minute 5 Assemble your filtration apparatus as shown to the right 6 Pour the strawberry slurry into the filtration apparatus and let it drip directly into your test tube 7 Slowly pour cold ethanol into the tube OBSERVE 8 Dip the loop or glass rod into the tube where the strawberry extract and ethanol layers come into contact with each other OBSERVE The A Science Behind D Food Qe fin Conclusions and Analysis 1 Itis important that you understand the steps in the extraction procedure and why each step was necessary Each step in the procedure aided in isolating the DNA from other cellular materials Match the procedure with its function PROCEDURE FUNCTION A Filter strawberry slurry through cheesecloth ___ To precipitate DNA from solution B Mush strawberry with salty soapy solution Separate components of the cell C Initial smashing and grinding of strawberry ____ Break open the cells D Addition of ethanol to filtered extract Break up proteins and dissolve cell membranes 2 What did the DNA look like Relate what you know about the chemical structure of DNA to what you observed today Explain what happened in the final s
22. tely incomplete answers will receive partial credit What is genetic engineering 2 points What two organisms did you combine 2 points Why did you combine these two organisms 2 points What traits does your genetically engineered organism have 2 points What is one advantage and one disadvantage to your genetically engineered organism 2 points 10 TOTAL POINTS Write your paragraph in the box below DNA Teacher Preparation Notes by Dr Jennifer Doherty and Dr Ingrid Waldron Department of Biology University of Pennsylvania 2011 Teaching Points e DNA is a nucleic acid made of two strands of nucleotides wound together in a spiral called a double helix e Each nucleotide is composed of a sugar molecule known as deoxyribose a phosphate group and one of four different nitrogenous bases adenine A thymine T guanine G or cytosine C e The phosphate and sugar parts of the nucleotides form the backbone of each strand in the DNA double helix e The bases extend toward the center of the double helix and each base in one strand is matched with a complementary base in the other strand in accord with the base pairing rules A pairs with T and G pairs with C e These characteristics are the same for the DNA of all organisms The DNA of different organisms differs in the sequence of nucleotides and these differences in nucleotide sequence are responsible for the genetic differences between different
23. tep when you added ethanol to your strawberry extract Hint DNA is soluble in water but not in ethanol A person cannot see a single cotton thread 100 feet away but if you wound thousands of threads together into a rope it would be visible much further away Is this statement analogous to our DNA extraction Explain Why is it important for scientists to be able to remove DNA from an organism List two reasons Is there DNA in your food How do you know Name Engineering Journal Period Date ASK What questions do you have to clarify the criteria or constraints of the project What prior knowledge can you tap IMAGINE Brainstorm possible solutions You may list describe draw PLAN Choose one idea and draw a prototype Include a description explanation if desired CREATE Follow your plan Modify as necessary to make it work Explain any modifications here EXPERIMENT Test your prototype Collect data and record it here IMPROVE Analyze data Repeat the engineering design process to optimize the product ASK What questions do you have to clarify the criteria or constraints of the project What prior knowledge can you tap PLAN Choose one idea and draw a prototype Include a description explanation if desired EXPERIMENT Test your prototype Collect data and record it here IMAGINE Brainstorm possible solutions You may list describe draw
24. that enclose the cells as well as the nuclei membranes within the cells DNA is released into the solution Detergent and the salt also help strip away the proteins that are associated with the DNA molecules e DNA is not soluble in alcohol whereas the other cell parts are By adding alcohol DNA precipitates out of the solution and collects at the interface of the alcohol and soap layer The colder the alcohol the less soluble the DNA will be in it so it is best to keep the alcohol in a freezer Homework Activity Optional e Genetic Engineering Worksheet If were a Genetic Engineer worksheet attached Extensions e More open ended Inquiry have students investigate effects of o types of strawberry frozen vs fresh types of sample banana strawberry cheek cells type of alcohol isopropyl vs ethanol concentration of alcohol 70 vs 91 temperature of alcohol room temp vs ice cold type of strainer coffee filter vs cheesecloth type of detergent Dawn vs Palmolive O 0 0 0 0 0 e Engineering o developing a kit to extract most DNA at least cost process engineering e Math o cost of extraction unit of DNA o mass of DNA extracted mass of original sample o business sell DNA necklaces e Technology o interactive whiteboard o video clips simulations o discuss the technology of DNA extraction 1000 for your genome newspaper articles o documentation user s manual video photos sharing o graphing
25. udents understanding and ability to communicate scientific concepts Discuss why each step was needed and how this relates to the organization of genetic material Extension The yield of DNA in this lab may be compared to that of the DNA Banana Extraction lab Compare ploidy levels and how it may relate to the amount of DNA recovered Use varying concentrations of ethanol 70 100 to determine how ethanol concentration qualitatively affects the yield of DNA Name Date DNA Extraction Strawberry The A Science Behind ig Food e fin Background The long thick fibers of DNA store the information for the functioning of the chemistry of life DNA is present in every cell of plants and animals The DNA found in strawberry cells can be extracted using common everyday materials We will use an extraction buffer containing salt to break up protein chains that bind around the nucleic acids and dish soap to dissolve the lipid fat part of the strawberry cell wall and nuclear membrane This extraction buffer will help provide us access to the DNA inside the cells Pre lab questions gt had 6 1 What do you think the DNA will look like 2 Where is DNA found Materials heavy duty ziploc bag 1 strawberry 10 mL DNA extraction buffer soapy salty water cheesecloth funnel 50mL vial test tube glass rod inoculating loop or popsicle stick 20 mL ethanol Procedure Cheesecloth 1 Place one strawbe
26. under the alcohol layer The high salt concentration from the sports drink and meat tenderizer is also important since DNA molecules are negatively charged and the salt neutralizes the repulsion among the negatively charged strands of DNA and allows the DNA to clump together This activity combines hands on extraction of DNA from human cheek cells with questions on DNA structure and replication that students answer during the wait times for DNA extraction For question 3 on page 5 you may want to substitute an alternative hands on simulation version in which students use nucleotide diagram pieces and tape to carry out DNA replication templates for the nucleotide diagram pieces are provided in the Teacher Notes available at http serendip brynmawr edu exchange bioactivities DNA If you prefer to extract DNA from samples other than human cheek cells we recommend the procedure for extracting DNA from split peas available at http learn genetics utah edu content labs extraction howto The directions for preparing the mixture of peas salt and detergent to pour in test tubes will produce enough mixture for 24 15 mL test tubes then your students can carry out the steps of adding enzymes and alcohol and pulling out the DNA In our experience you may want to use the blender for slightly longer than 15 seconds you should not be surprised when you have a lot of leftover peas after the straining step you can use somewhat less alcohol than suggest
27. yme that cuts proteins into small pieces As this enzyme cuts up the proteins the DNA will unwind and separate from the proteins Step 3 Alcohol Using a pipette slowly add cold rubbing alcohol into the test tube let the alcohol run down the side of the test tube so it forms a layer on top of the soapy liquid Add alcohol until you have about 2 cm of alcohol in the tube Alcohol is less dense than water so it floats on top Do not mix or bump the test tube for 10 minutes DNA molecules will clump together where the soapy water below meets the cold alcohol above and you will be able to see these clumps of DNA as white strands Why am I adding alcohol The cold alcohol reduces the solubility of DNA When cold alcohol is poured on top of the solution the DNA precipitates out into the alcohol layer while the lipids and proteins stay in the solution Making Your Necklace By now your DNA should be visible as clumps of white strands floating in the alcohol layer There may be air bubbles attached to the strands Use a pipette to suck up your DNA from the test tube and transfer it to the small capped tube Fill the small capped tube the rest of the way with alcohol Close the cap of the tube around a piece of string Now you have a necklace with your very own DNA Your assignment Performance Task Create a kit to extract cheek cell DNA to make a necklace Your kit should contain a user s manual with background information on DNA and how
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