Need help for science project

[Neelu]

My daughter is in 5th grade and she has decided to do a science project on extracting DNA from an onion and strawberry.Well,should she do a comparison on which one will give more strands of DNA between a strawberry and an onion? Can you suggest something else which she can determine through scientific experiment regarding DNA which is more appropriate to her grade level. It would be a great help if you can suggest how the project will stand as in her school science fair?

[amyc]

Hi - I wanted to post the links to the projects you've mentioned here so our Experts can easily refer to the projects it sounds like your daughter is using.

Extracting Onion DNA
https://www.sciencebuddies.org/science- ... p001.shtml
(Approx Grades 6-8)

Do-It-Yourself DNA
https://www.sciencebuddies.org/science- ... p015.shtml
(Approx Grades K-5)

Is it the first one she has decided to do?

Amy
Science Buddies

[MelissaB]

I think that this is an age-appropriate project. She should extract DNA multiple times from onions and strawberries and take an average for the DNA amounts for each group, but aside from that I think it is OK.

If she wants to make it more difficult, she might try looking at a variety of fruits and vegetables to try to determine if she can see which ones are related by the amount of DNA she can extract.

[sunmoonstars]

If she wants to make it more difficult, she might try looking at a variety of fruits and vegetables to try to determine if she can see which ones are related by the amount of DNA she can extract.

Melissa, can you be more specific on how she would do this comparison? The only thing I can think of is sequencing, which won't be age-appropriate.

Another idea to customize this project is to see if you can extract more or less DNA from aged fruit versus fruit that isn't ripe yet. Or she could change a reagent or a step in the procedure and see if it increases the yield of DNA or not.

[Neelu]

Hi this is my first time doing this kind of projects,so it was a bit difficult for me to understand about DNA.Will I be able to count the strands of DNA with naked eyes or do I need some other tool.I liked the idea about taking an average of the number of strands.Also,I had another question;How should I word my Problem/Purpose in my report?And Do you know any other fruit or vegetable which has a lot of DNA and which the DNA is easy to be spooled according to my age?I really appreciate the help.

[sunmoonstars]

Hi Neelu,

The individual strands are too small to count, and when you have the DNA spooled at the end of the project, the DNA will look like a glob of white stuff (which is all the strands wound up together in a big mess). Quantitating the amount of DNA you have can be done by weight. We explain a bit more about how to do that in the variations section of this project: https://www.sciencebuddies.org/science- ... p015.shtml Once you have weights for the DNA, you can make comparisons of those weights.

My suggestion for wording the question is something like this:

Which yields more DNA, strawberries or onions?

Or, if you were to use only strawberries and want to compare ripe fruit and unripe fruit, you could ask:

Does ripeness of a fruit affect the amount of DNA that can be extracted?

[sciencediplomat]

Hi Neelu!

The experts have covered everything, but I just wanted to add my part.

I myself did this project in a biology class last year and just wanted to say that the procedures are not time-consuming or difficult. It took less than forty-five minutes. I think you will place well for someone your age and category. Just show the judges you care which is very important and try to describe everything in detail and depth. This project was interesting and I think it helps seeing something like DNA in a clump to better understand and associate it when you read about it.

This is just some background from one of my old worksheets “Berry Full of DNA” it's just some background : Every cell in a strawberry contains eight copies of each of its chromosomes. As a result, strawberries contain large amounts of DNA.Strawberry DNA is easy to extract because strawberries are easy to mash and ripe strawberries produce enzymes that contribute to the breakdown of cell walls. To extract the DNA you will first break strawberry cells apart mechanically, by crushing them. Next you will add detergents to dissolve the cell’s plasma membranes. A filtering step using cheesecloth then removes cell organelles, broken cell walls, membrane fragments, and other cell debris. The result will be a red colored solution containing DNA and other small dissolved molecules such as sugars and proteins. When cold ethanol is layered on top of this solution molecules of ethanol repel the DNA molecule causing it to clump. A ropelike clump forms large enough for the eye to see.

Unfortunately I didn’t participate in a lab extracting onion DNA but I would infer it’s similar and I included some more links under onions


Last Thing!Referencing to your question about other fruits about which have more DNA , strawberries are octoploid and have the most!


Here are some links to guide and help you.And if you have any questions Ill be happy to answer!
Links: http://www.gs.washington.edu/outreach/d ... cedure.pdf

http://www.biotechinstitute.org/resourc ... s_lab.html

http://www.biotechinstitute.org/resourc ... s_lab.html
This link has more ideas so you could expand your project it you wanted to!For instance exploring if the ethanol concentration affects how much DNA you receive.Just an idea!

Onion links:
http://www.biotech.iastate.edu/lab_prot ... Onion.html

https://www.msu.edu/course/lbs/145/luckie/OnionDNA.pdf

[kehufker]

By choosing an onion and a strawberry, are you trying to compare the amount of DNA between fruits and vegetables? Just remember each is only representative and it is important not to make too many generalizations. If you wanted to broaden your project even more, it is also easy to extract DNA from wheat germ using a process identical to the one you are using on the strawberries. Also be sure to make sure you take into account the weight of the DNA relative to the amount of strawberry, onion, etc. that you started with. It sounds like you will have a great project.