DNA, RNA, & Crime, Oh My! (Modified Snorks Activity)

This is a fun and creative activity to tie all of the following concepts together into one lesson: DNA sequencing & transcription, mRNA translation, amino acid codons & proteins, genotype, phenotype, recessive & dominant alleles & traits.

 

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Students will help solve a crime based on DNA evidence left on a lollipop at the crime scene. There are 3 versions of the same scenario that will identify 3 different criminals so you can use them for 3 classes – this avoids having the kids tell the next class who the suspect is ;). Each student will receive one of the 4 DNA samples – you can have students work individually, or have a group of students work on suspect 1, another on suspect 2, etc. (Sorry – I do not have an answer key to post)

Directions: Worksheets: DNA-RNA-Crime-Snorks-2018 & Amino Acid Codon Wheel, & additional resource: 20 Amino Acids

  • Step 1 – students will transcribe the DNA sequences into mRNA sequences
  • Step 2 – using the Amino Acid codon wheel, they will determine the amino acid for each codon
  • Step 3 – using the chart, they will find protein using the sequence of amino acids
  • Step 4 – using the proteins, they will determine the phenotype
  • Step 5 – using the phenotypes, they will determine the genotype(s)
  • Step 6 – is their suspect the criminal?
  • Step 7 – they will draw a mug shot of their suspect using the phenotypes they decoded

This lesson was modified from the one found on Biology Corner: https://www.biologycorner.com/worksheets/DNA_snorks.html 

 

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Diffusion Lab – Iodine & Cornstarch

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Materials and Set Up – this was so easy and inexpensive to do and had the same effect as using dialysis tubing. Great demo/lab as part of our unit on osmosis and diffusion!

For every two students:

  • handout from Biology Corner
  • large beaker
  • inexpensive sandwich bag – non sealing (I used Wegmans 150 ct)
  • 1 tbsp corn starch
  • 50 mL water
  • rubber band
  • clothes pin
  • graduated cylinder
  • 100 mL Iodine dilution

Iodine Preparation

  • 20 ml Iodine added to 500 mL of water
  • measure out 100 mL of diluted iodine for each group

Prelab Prep:

  1. Place one bag over each beaker
  2. Add 1 tbsp of cornstarch to each bag
  3. Add 50 mL of water to each bag
  4. Check for leaks
  5. Use a rubber band on each one to keep closed
  6. Clip bag to beaker

Observations

  1. Students will add iodine and make observations – changes will take place within a few minutes and the longer it sits, the darker it will become.
    1. Iodine is able to pass through the plastic bag, the starch is not
  2. Have students lift the bag out to see the changes that are taking place
  3. Discuss

Update – I let the set up sit over the weekend, and when I came in today, the water was almost completely clear – looks like just about all of the iodine moved into the bag:

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Sheep Head Dissection – Brains, Tongues, and Eyes

Our 7th grade team is revamping the science curriculum to include more dissections. Our focus in 7th grade is The Cell, Genetics, and the Human Body. Last year, we introduced the sheep heart dissection and it was such a great experience for our students. As far as dissections go, I do not like to use preserved specimens – they are often rubbery, pale yellow to beige in color, and look and feel so different than what the specimen is like in its original form. We ordered frozen sheep hearts from the butcher, thawed them in the fridge, and they were able to dissect a heart and see so much more detail than a preserved specimen.

This year, we wanted the students to dissect a sheep brain and didn’t want to use a preserved specimen. There was one ‘problem’, the head came with it. I didn’t see that as problem, instead my first reaction was – “We can dissect the eyes, too!”

The frozen heads were sawed in half so that each group could have half a skull to work on. (We kept some heads intact so that the students could make observations on those as well. Next year I will ask the butcher to saw them in half before they ship them to us.) My husband sawed them in half perfectly (thanks honey!) and it was amazing to see the internal anatomy – the brain, the sinus cavity, the tongue, the teeth, the muscles of the face, the eye in the eye socket, the lip – everything fitting together perfectly and all of it was perfect healthy tissue.

Once we had the heads prepared, and in the freezer, our next concern was student reaction. Would this be too much for them to handle? Would a lot of students opt out? We discussed the sheep head dissection with our students, and answered any and all questions they had. We expressed that they had options with how involved they wanted to be in the dissection process, that there were alternative options available, and we had them complete a quick Google survey. We wanted their honest answers and they were able to change their mind, either way, once the dissections started.

These were the survey choices:

  1. I am comfortable making observations, and handling the specimen and the dissecting tools
  2. I think I might be comfortable handling the specimen, tools, and making observations
  3. I don’t want to handle the specimen, but I would like to observe and take notes for my group
  4. I want to be in the room but keep my distance and get closer to the specimen as I get more comfortable
  5. I can’t be in the room for personal or religious reasons

Below are the student responses:Screen Shot 2016-02-26 at 7.20.04 PM

All of our students were involved in some way based on their comfort level and the dissection was a huge success, something that they will always remember.

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Some tips for the Sheep Head Dissection:

Storage – large 1 gallon zip top bags can be used to store the 1/2 sheep skull in the fridge or freezer. Whole heads would be stored in a plastic shopping bag – grocery store size. Students names should be written on the bags with a permanent marker prior to any dissections starting. If frozen, half skulls will need to be out a few hours to thaw, whole skulls at least 6 hours. Thawing them the day before then placing them in the fridge works well.

Cleaning up – Lots and lots of newspaper and disinfecting wipes. This made clean up faster and easier. Students were able to wipe down their goggles, then the trays and equipment. Also, triple bag any garbage to avoid leaking and remove from classroom quickly. Since the specimens are food grade, they are able to be thrown out like kitchen refuse.

Dissection equipment – disposable scalpels are the better option, cleaning the scalpels was very time consuming – I did this at the end of the dissection, students did not take scalpels apart for safety reasons. It included removing and disposing the used blades and disinfecting the handles and replacing/screwing on new blades. Also, a few scalpels broke while the students used them. You do not need dissecting trays – aluminum foil trays, esp the ones that come with covers, are a good option. You can keep all your tools in the cover so they are easy to find and won’t get lost or thrown out by accident. When we were done with the dissection, I soaked & washed everything in a bleach solution to disinfect prior to storage.

Reference Material – We printed out diagrams and photos that were laminated and placed on the desks for students to use (we searched Google for images that were clear and easy to see structures with). This was really helpful when identify structures during the dissection. The laminated sheets were used during each class over several days, we did not have to worry about them getting wet or funky while we used them. You can also wipe them down after each class. To guide students during the dissection, we used a simple check list of items we wanted the students to observe. You can laminate this as well and use an Expo marker to check off  items:

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Post – Lab – we discussed the sheep dissection as a class and the students provided great insight and feedback. Instead of a formal lab report, we asked the students to write a one page reflection about their experience.

 

DNA – Paper Protein Chains Activity

DNA-paper-protein-chains
Making protein chains – In this example, the color code is different than posted in the lesson, it was a prototype

Purpose:

  • Students will convert their name into a DNA sequence and create a protein chain.

Materials:

  • Student Handout (DNAPaperProteinChainsActivity)
  • Amino Acid Handout (link)
  • pre-cut 2 inch wide strips of construction paper  (12×18) in the following colors – red*, pink, yellow, orange*, green, lt. blue, dk.blue, and black*
    • (*) be sure to have more of these colors since they are vowels
    • I used a paper cutter and was able to make a lot of strips very quickly ahead of time
  • markers
  • staplers
  • clothes pins and string to hang up in classroom

 

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Protein Chains made by M.P.’s class Dec. 2017

Procedures:

  1. This activity should be used after DNA and protein synthesis has been introduced. This activity will help reinforce the concept of how the sequence of DNA codons create specific amino acids, and in turn, the amino acids are joined together to create specific proteins. (link)
  2. Each student will write the letters from their first and last name onto the student handout.
  3. Using the chart, they will find the amino acid associated with the first letter of their first name.
  4. For example, if the first letter is “L”, it will code for Leucine. They will select one of the codons for Leucine and write it on their chart.
  5. Write the color of the paper link they will need for “L”, in this case, it is Red.
  6. Repeat for every letter in their name.
  7. Once their handout is completed, they will select the colored links, one for each letter of their name.
  8. The colored links will be placed in the same order as the letters in their name.
  9. On each link, write one of the codons for that letter. For example, “L” would be “CTT” on a Red link.
  10. Loop and staple the first letter of their name.
  11. Weave through the second letter and staple the loop closed.
  12. Continue until all the letters have been linked together.
  13. Hang up the protein chain, be sure to have the first letter of their name at the top.
  14. Look for patterns – what color was used the most? Which group of amino acids was it? Which group of amino acids was used the least? Who had the longest name? Etc.

Protein Synthesis (link)

Parts of the Cell: Using the Jigsaw Method to learn about Organelles

Updated October 2018 – Instead  of doing this as a jigsaw activity, each group comes up with an analogy for each cell organelle based on their chosen theme. Each group then presents their theme and analogies to the class. Below are some sample slides for one group’s theme which was our school:

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This is an updated version on how to use the ‘Jigsaw Method’ for students to learn about cell organelles that includes a tech component –  each expert group will create Power Point slides for their assigned organelles. When each expert group is done, they will have one complete set of slides that they will use to teach each other in their home groups, use as a resource to review at home, and/or print out flashcards (4-6 slides per page) if needed.

Materials

  • Desktop/Laptop/Tablet with Internet Access
  • Google Slides Template (public link)
    • One shared google doc per home group
    • To save this ppt – click on “File” then “Make a Copy” or “Download as” and choose the format you would like. Please do not request editing access to this file – that would change my version of this slide show.
  • Worksheet for 4 expert groups (pdf)
  • Worksheet for 5 expert groups (pdf)
    • this allows for less information per expert group, but larger home groups

Links for research 

  1. BrainPOP Cell Video (free link)
  2. BrainPOP Cell Structures Video (link)
  3. Biology 4 Kids – Cell Structure (link)
  4. Cells Alive (link)
  5. Harcourt School (link)
  6. Khan Academy Video (link)
  7. I Know That (link)
  8. Plant cell Video (link)

Group 1 contains an expert from A, B, C, & D. All of the “A” members will sit together to research their assigned organelles. Each member of group A will research and create their own slides for the Nucleus (slide 2), Nucleolus (slide 3), Chromatin (slide 4), and Centrioles (slide 5). Home group members (B, C, & D) will add their information to the rest of the slides at the same time A is adding information from the A expert group.

On each slide, they will include the following information:

  • Name of organelle
  • Location (Nucleus or Cytoplasm?)
  • Plant, Animal, or Both?
  • Function
  • Images of the organelle
  • Image of an analogy for that organelle

Encourage students to use the animation feature to have the information appear sequentially instead of seeing all the information as soon as they advance to the next slide. This will help with note taking when they are presenting their information to their home group.

After each expert group is done with their research, they will return to their home group. The member from group A will go first, and using presentation mode in Google Slides (via desktop/laptop/tablet) they will teach their home group about the nucleus, nucleolus, chromatin, and centrioles. Members B, C, and D will write their notes on the handout provided. When A is done, the member from expert group B (via desktop/laptop/tablet) will present his/her organelles in the same manner.

If possible, having each student use their own laptop or desktop for the research phase (expert groups) and then only one laptop or tablet for the presentation part (home group) would be the best option so that their focus is on the person who is presenting.

Additional Resources

  • Cells Worksheet (ScienceSpot link)
  • Animal Cell Coloring (link)
  • Plant Cell Coloring (link)
  • For more information on how to use the Jigsaw Method – (link)