Ripe strawberries are an excellent source for extracting DNA because they are easy to pulverize and contain enzymes called pectinases and cellulases that help to break down cell walls. And most important, strawberries have eight copies of each chromosome (they are octoploid), so there is a lot of DNA to isolate.
- 1 Why are strawberries and bananas used for DNA extraction?
- 2 What is the hypothesis for strawberry DNA extraction?
- 3 Do strawberries have more chromosomes than humans?
- 4 Why are strawberries selectively bred?
- 5 Why do frozen strawberries yield more DNA?
- 6 What are possible errors in strawberry DNA extraction lab?
- 7 Why is a ripe banana a better sample for DNA extraction compared to an unripe banana?
Why are strawberries and bananas used for DNA extraction?
DNA, or deoxyribonucleic acid, is where genetic information is stored. Every living thing has DNA, and it acts as an instruction manual for life as it encodes cells with directions on how to grow, divide, and behave. Information is encoded in the double helical strands that are bound together by patterns of base pairs.
- These base pairs include adenine, guanine, thymine, and cytosine.
- The order that these base pairs line up provides the cell with directions for the production of amino acids that can be deciphered using the universal genetic code.
- These amino acids can then work to create the proteins that function in almost every aspect of life! So, how do fruits come into play? Well, fruits are also living organisms.
All plants, animals, and even microorganisms have DNA, and in this experiment the DNA will be extracted from bananas and strawberries. We specifically use fruits like strawberries and bananas because they are octoploid and triploid, respectively. This means that each strawberry cell has eight sets of DNA, and each banana cell has three sets, so there is a lot available for extraction.
- Here’s a fun fact too! Humans, DNA-wise, only differ from one another by 0.1%, so in that small 0.1% lies all of the human diversity on earth.
- The structure of DNA also comes into play when discussing this experiment.
- In its natural state DNA is housed in the nucleus of the cell.
- When the detergent is added, the cells lyse, or break open, by dissolving the phospholipid bilayers that compose the membranes.
As a result, the DNA is allowed to flow out of the cell and into the surrounding solution. Lastly, DNA is not soluble in isopropanol, or rubbing alcohol, and the colder the better in this case. So, once the DNA is out of the cell and into the rubbing alcohol mixture it can easily be extracted.
Why do strawberries yield more DNA than other fruits?
1) Strawberries are soft and easy to pulverize or smash 2) Strawberries yield way more DNA than other fruits because they are octoploid, meaning that they have eight copies of each type of DNA chromosome. Other cells often contain one or two copies.
What is the hypothesis for strawberry DNA extraction?
Hypothesis – The hypothesis is that the temperature of the Ethanol affects the amount of DNA extracted from a Strawberry. My hypothesis is that the hot ethanol at temperature 62 C might not work because the ethanol might evaporate, then there won’t be enough Ethanol to break the cell wall.
How was DNA extracted from the strawberries?
Squishy Science: Extract DNA from Smashed Strawberries A genetically geared activity from Science Buddies Advertisement Key concepts DNA Genome Genes Extraction Laboratory techniques Introduction Have you ever wondered how scientists extract DNA from an organism? All living organisms have DNA, which is short for deoxyribonucleic acid; it is basically the blueprint for everything that happens inside an organism’s cells.
Overall, DNA tells an organism how to develop and function, and is so important that this complex compound is found in virtually every one of its cells. In this activity you’ll make your own DNA extraction kit from household chemicals and use it to separate DNA from strawberries. Background Whether you’re a human, rat, tomato or bacterium, each of your cells will have DNA inside of it (with some rare exceptions, such as mature red blood cells in humans).
Each cell has an entire copy of the same set of instructions, and this set is called the genome. Scientists study DNA for many reasons: They can figure out how the instructions stored in DNA help your body to function properly. They can use DNA to make new medicines or genetically modify crops to be resistant to insects.
They can solve who is a suspect of a crime, and can even use ancient DNA to reconstruct evolutionary histories! To get the DNA from a cell, scientists typically rely on one of many DNA extraction kits available from biotechnology companies. During a DNA extraction, a detergent will cause the cell to pop open, or lyse, so that the DNA is released into solution.
Then alcohol added to the solution causes the DNA to precipitate out. In this activity, strawberries will be used because each strawberry cell has eight copies of the genome, giving them a lot of DNA per cell. (Most organisms only have one genome copy per cell.) Materials
Rubbing alcohol Measuring cup Measuring spoons Salt Water Dishwashing liquid (for hand-washing dishes) Glass or small bowl Cheesecloth Funnel Tall drinking glass Three strawberries Resealable plastic sandwich bag Small glass jar (such as a spice or baby food jar) Bamboo skewer, available at most grocery stores. (If you use a baby food or short spice jar, you could substitute a toothpick for the skewer.)
Chill the rubbing alcohol in the freezer. (You’ll need it later.) Mix one half teaspoon of salt, one third cup of water and one tablespoon of dishwashing liquid in a glass or small bowl. Set the mixture aside. This is your extraction liquid. Why do you think there is detergent in the extraction liquid? Completely line the funnel with cheesecloth. Insert the funnel tube into the tall drinking glass (not the glass with the extraction liquid in it). Remove and discard the green tops from the strawberries.
Put the strawberries into a resealable plastic sandwich bag and push out all of the extra air. Seal the bag tightly. With your fingers, squeeze and smash the strawberries for two minutes. How do the smashed strawberries look? Add three tablespoons of the extraction liquid you prepared to the strawberries in the bag. Push out all of the extra air and reseal the bag. How do you think the detergent and salt will affect the strawberry cells? Squeeze the strawberry mixture with your fingers for one minute. How do the smashed strawberries look now? Pour the strawberry mixture from the bag into the funnel. Let it drip through the cheesecloth and into the tall glass until there is very little liquid left in the funnel (only wet pulp remains). How does the filtered strawberry liquid look? Pour the filtered strawberry liquid from the tall glass into the small glass jar so that the jar is one quarter full. Measure out one half cup of cold rubbing alcohol. Tilt the jar and very slowly pour the alcohol down its side. Pour until the alcohol has formed approximately a one-inch-deep layer on top of the strawberry liquid. You may not need all of the one half cup of alcohol to form the one-inch layer. Do not let the strawberry liquid and alcohol mix. Study the mixture inside of the jar. The strawberry DNA will appear as gooey clear/white stringy stuff. Do you see anything in the jar that might be strawberry DNA? If so, where in the jar is it? Dip the bamboo skewer into the jar where the strawberry liquid and alcohol layers meet and then pull up the skewer. Did you see anything stick to the skewer that might be DNA? Can you spool any DNA onto the skewer? Extra: You can try using this DNA extraction activity on lots of other things. Grab some oatmeal or kiwis from the kitchen and try it again! Which foods give you the most DNA? Extra: If you have access to a milligram scale (called a balance), you can measure how much DNA you get (called a yield). Just weigh your clean bamboo skewer and then weigh the skewer again after you have used it to fish out as much DNA as you could from your strawberry DNA extraction. Subtract the initial weight of the skewer from its weight with the DNA to get your final yield of DNA. What was the weight of your DNA yield? Extra: Try to tweak different variables in this activity to see how you could change your strawberry DNA yield. For example, you could try starting with different amounts of strawberries, using different detergents or different DNA sources (such as oatmeal or kiwis). Which conditions give you the best DNA yield?
Observations and results Were you able to see DNA in the small jar when you added the cold rubbing alcohol? Was the DNA mostly in the layer with the alcohol and between the layers of alcohol and strawberry liquid? When you added the salt and detergent mixture to the smashed strawberries, the detergent helped lyse (pop open) the strawberry cells, releasing the DNA into solution, whereas the salt helped create an environment where the different DNA strands could gather and clump, making it easier for you to see them.
(When you added the salt and detergent mixture, you probably mostly just saw more bubbles form in the bag because of the detergent.) After you added the cold rubbing alcohol to the filtered strawberry liquid, the alcohol should have precipitated the DNA out of the liquid while the rest of the liquid remained in solution.
You should have seen the white/clear gooey DNA strands in the alcohol layer as well as between the two layers. A single strand of DNA is extremely tiny, too tiny to see with the naked eye, but because the DNA clumped in this activity you were able to see just how much of it three strawberries have when all of their octoploid cells are combined! (“Octoploid” means they have eight genomes.) More to explore from the Tech Museum of Innovation, Stanford School of Medicine, from the Tech Museum of Innovation, Stanford School of Medicine from Learn Genetics, the University of Utah, from Science Buddies This activity brought to you in partnership with Discover world-changing science. : Squishy Science: Extract DNA from Smashed Strawberries
Do strawberries have more chromosomes than humans?
2. Humans have 23 pairs of chromosomes, for a total of 46. Strawberries have 7 chromosomes, but they are octoploid. Some Bananas are triploid (3 copies) and have 11 individual chromosomes.
What are the differences in DNA between strawberries and bananas?
Strawberries have 7 chromosomes, so they have a total of 56 chromosomes in every cell. Bananas are triploid, which means they have 3 copies of each type of chromosome inside the nucleus of each cell. Bananas have 11 chromosomes, so they have a total of 33 chromosomes in every cell.
Why are strawberries selectively bred?
Abstract – In the last few years the nutritional value of fruit has been widely studied and requested by the consumers, especially for protection against cardiovascular events, cancer and others as well as for the general health benefits it can provide.
- These benefits can be ascribed mainly to the Total Antioxidant Capacity (TAC) of fruit which is determined by a complex combination of bioactive compounds, generally related to specific characteristics of the genotype and of its interaction with the environment.
- Strawberry breeding programs are currently used to acquire new varieties improved for specific agronomic (Yield and Size), qualitative (Firmness, Sugars Content and Acidity) and sensorial (Colour and Aroma) characteristics, all combined to increased disease resistance and plant adaptability.
Nowadays, besides to all these parameters is necessary to look for the specific bioactive components well known for their effect on human health. This aspect is now highly requested by the consumer. By testing different commercial strawberry varieties, a wide difference among their production and fruit quality, mostly related to their adaptability to the local evaluation conditions, is generally detected.
Regarding their nutritional values, only few varieties nowadays differ for their higher phenol content and total antioxidant capacity. By taking into account this knowledge different breeding programs specifically addressed to increase fruit nutritional value, have been started. A first approach is based on the use of inter-specific crosses within wild and cultivated genotypes, so to increase variability for these characters, while the second by considering the intra-specific crosses within cultivars already known for their agronomic behavior and good quality performance.
Herewith, we report on the major aspects related to breeding program aimed to increase strawberry fruit nutritional quality and what we can expect for the improvement of consumer acceptability of this fruit.
What is the most effective DNA extraction method?
Silica Gel Based Techniques – In the spin-column DNA extraction technique, a silica gel as a solid phase is immobilized in a tube. A specially prepared lysis buffer is used to digest the sample and allows it to separate on a solid phase. the sample is Centrifuged first to remove all the debris by protecting the DNA and changing the pH of the solution(to elutes DNA in the last step).
- These techniques are now commercially available.
- Spin column is the most advanced, effective, rapid and accurate separation technique.
- It is, however, a chemical method of DNA extraction but works on the principle of solid-phase separation.
- The main advantage of this technique is that can isolate DNA from any biological sample and tissue.
However, it is difficult to isolate DNA from plants even using the spin-column technique, Different columns are now available depending upon the sample type. But this technique is Cost, lacks optimizations and the yield remains comparatively low but good.
Why do frozen strawberries yield more DNA?
Boiling and Freezing the strawberries may have improved the yield of DNA in solution by helping break down the cell membrane allowing more DNA into solution.
What are possible errors in strawberry DNA extraction lab?
Source of Error: The possible sources of experimental error is the percentage of isopropyl alcohol used. For the strawberry and onion DNA extraction, 85% isopropyl alcohol was used whereas for the banana DNA extraction, 70% isopropyl alcohol was used due to that being the only source of isopropyl alcohol available.
What affects DNA extraction in fruit?
– The solution of washing-up liquid, water and salt, is great at breaking up the fruit cells. – Washing-up liquid bursts the cells that make up the fruit (much like detergent cuts through grease when cleaning). – Salt helps in this process of releasing DNA from the cell.
Does ripeness of fruit affect DNA extraction?
Because DNA is stored in cells, the amount of extractable DNA in fruit is decreased as cells are destroyed in the ripening process.
Why is a ripe banana a better sample for DNA extraction compared to an unripe banana?
The under ripe does not produce very much enzymes so it yields less DNA. This means that when bananas ripen its nutritional value increases and when kiwis and strawberries ripen their nutritional value increases. Today, scientists are able to study the genetic code called DNA.