DNA Extraction of Fruits

Report on DNA Extraction from fruits Aim The experiment is carried out to extract the DNA from many different kinds of fruit with DNA extraction method. Introduction All living organisms have Deoxyribonucleic acid (DNA) in their cells. Both eukaryotes and prokaryotes have DNA except one has it in nucleus while the other has it in the cytoplasm itself. DNA is what defines an organism where it contains genetic code. Every living organism possible has different genetic code each. According to Rettner (2017), the DNA is a double helix strand and has a ladder-like shape to it. Rettner (2017) also mentioned that DNA strands are so long they coil tightly into chromosomes. The DNA is formed by many monomers known as the nucleotide. The nucleotide consists of three components, according to Bailey (2017) are the pentose sugar, the phosphate group and the nitrogenous base which plays an important role in genetic coding. The nitrogenous base, also a statement by Bailey (2017), are Adenine, Thymine, Cytosine and Guanine but only one can exist in a nitrogenous base at a time. It is mentioned by Woodhouse (2017) that, Adenine base of the nitrogenous base can only pair with Thymine base of another nitrogenous base while Cytosine base can only pair with Guanine of the other nitrogenous base. Adenine pairing with Thymine base is said to have a double hydrogen bond while a triple hydrogen bond for Cytosine and Guanine. Woodhouse (2017) also mentioned how there can only be pairing of purines and pyrimidines thus having the rule of Adenine base to Thymine base while Cytosine base to Guanine base. Nucleotides connect with other nucleotides where the nitrogenous base is involved in base pairing forms a long chain which coils into a helix shape. This is where the double helix chain start to coil around a substance known as the histone and slowly coil into chromatin. It can be further condensed in cell division. DNA can be extracted by the DNA extraction method where the extracted DNA can be put into good use. DNA can be used in the field of genetical engineering. Plants can have their genes engineered to improve their survivability and sustainability. The DNA of plants can be extracted and can have desirable trait transplanted into their genome. This trait will then be passed down to their upcoming generations. Animals can also have their DNA extracted by scientists and even have a clone of the animal itself cloned. The extraction of DNA is also needed when creating pharmaceutical products for example the Hepatitis B vaccine and human growth hormone. DNA can also be used in identifying a person’s identification where genetic material can be compared with suspected subject. DNA can also be used to determine paternity and maternity. DNA extraction is such an important procedure where it revolutionised modern technology. This experiment is the extraction of DNA from fruits with DNA extraction method. The experiment involves different variety of fruits that will have their DNA extracted by the conductors of the experiment. The conductors of experiment will then observe the result and see for themselves that how each fruit has their own unique chromosomal number. Materials and Equipment 1. 2. 3. 4. 5. 6. 7. 8. Strawberries (3) Cut Dragon Fruit fleshes (3) Plastic Bag (2) Cheesecloth (2) Cold Isopropyl alcohol (50ml) 100ml Beaker (2) 250ml Beaker (2) Knife Procedure 1. The green leaves on the strawberry are removed from it. 2. The strawberries are placed into a plastic bag and the bag is shut tightly. 3. The bag itself containing the strawberries is smashed thoroughly with hands for 1 minute. 4. 30ml of DNA extraction fluid is added into the plastic bag containing mashed strawberries. 5. The plastic bag is resealed again. 6. The mixture is gently mixed for 1 minute. 7. A cloth is laid over the opening of a 250ml beaker. 8. The strawberry mixture is poured carefully into the beaker through the gauze. 9. The strawberry mixture is left to filter for several minutes. 10. 25ml of cold isopropyl alcohol is poured into a 100ml beaker. 11. The strawberry mixture in the 250ml is poured slowly and carefully into the 100ml beaker containing 25ml of cold isopropyl. 12. Steps 1-12 are repeated with several other different fruits. Results Picture of Strawberry mixture and Isopropyl, the translucent and cloudy layer on top of the surface of the mixture is the DNA of the strawberry. The DNA of strawberry extracted from the alcohol ethanol can be seen obviously. Picture of Dragon-fruit mixture and Isopropyl, the translucent and cloudy layer on top of the solution is the DNA of the dragon-fruit. The DNA of dragon-fruit extracted can be seen obviously just like the extraction of strawberry DNA above. Both strawberry and dragon-fruit DNA can be seen easily after extraction due to great amount of DNA present in the mixture itself. Discussion 1) Explain why strawberries are a good source of DNA. Strawberries are a good source of DNA because they are octoploid. The characteristic of strawberries being an octoploid makes strawberries have 8 copies of chromosome instead of only 2 copies. Human body cells are diploid and so they only have 2 copies of chromosome. Due to strawberries having 8 copies of chromosome in each cell, extraction of DNA using strawberries is a simple task. 2) Why was is necessary to mash the strawberries? Mashing the strawberries is a necessary procedure so that a result can be obtained by the end of the extraction of DNA itself. Mashing the strawberries breaks the cell wall of the cell. This is so that the DNA materials are exposed for extraction. Mashing the strawberries or any other fruits in general used in the experiment ensures the ability of the conductor of the experiment to extract the DNA material out of it. 3) Explain why the amount of DNA obtained by each group is different. The amount of DNA obtained by each group is different due to how each group have different errors or not even have one at all in the process of conducting the experiment. Different groups have different mistakes if they committed them and each different mistake committed leads to different results. There are groups that might not even have a single mistake in their procedure of the experiment. Another reason why the amount of DNA obtained by each group is different is due to how each group uses different fruits and have their DNA extracted. Each different fruit have their own chromosome count in each cells which in this case strawberries are octoploid and have 8 chromosome copies. Other groups might not use strawberry in their experiment and therefore do not obtain the same result as compared to groups that use strawberry in their experiment. 4) Explain why the extraction fluid is used in this investigation. To make the extraction fluid, 50ml of dishwashing detergent and 2 teaspoons of salt was added to 900ml of water. The extraction fluid plays an important role in this experiment. Dishwashing detergent is needed to create an extraction fluid because the detergent can dissolve the cell membrane of the cells after the cell wall has been mechanically destroyed by mashing the fruit. The phospholipid bilayer will dissolve as a result of having detergent added into the mixture. Salt is also one of the substances needed to create the extraction fluid because salt removes protein that are bound onto the DNA. Salt also helps in dissolving the proteins in the aqueous layer so it does not precipitate in the alcohol along with the DNA. 5) What does it mean to be insoluble? Name a liquid in which DNA is insoluble. A substance is considered to be insoluble in the solvent if it does not dissolve in a solvent. Different solvents have different polarities therefore not everything can dissolve in it. DNA is insoluble in alcohol. This is due to how they have different densities and polarity that they cannot form a mixture. 6) What is the benefit of using cold, rather than warm, isopropyl alcohol? Cold isopropyl alcohol is used in the experiment instead of warm isopropyl because cold isopropyl can protect the DNA from enzymes attempting to degenerate it. Isopropyl with lower temperature that is cold in this experiment does not directly protect the DNA material but instead indirectly protects it by slowing down the enzyme activity in the cell. Enzymes in the cell tend to degrade the DNA material in the cell therefore using isopropyl alcohol with lower temperature instead of high temperature will slow down the enzyme activity and therefore indirectly protect the DNA. 7) If you had extracted DNA from animal cells instead of plant cells, what cell barrier would have been different? What do plant and animal cells have that bacterial cells do not? If the DNA extracted was animal cells instead of plant cells which are used in the experiment, the cell barrier would be different. There would not be an outer layer surrounding the plasma membrane of the cell known as the cell wall where there will only be plasma membrane. Bacterial cells have cell wall but the cell wall in the bacteria is different compared to the cell wall in plant cells. Cell wall in plant cells are made of cellulose while the cell wall in bacterial cell is made up of murein. Both plant and animal cells have nucleus while bacterial cells do not have a nucleus. Bacterial cells at the same time do not have mitochondria unlike both plant and animal cells having mitochondria. 8) Discuss why you cannot see the DNA double helix and how an organism’s DNA fits into the nucleus of the cell. DNA double helix cannot be seen because it is extremely small in size. Not even the latest microscopes can see DNA double helix unless when they condense and become thicker in size. To fit into the nucleus of a cell, the DNA wraps itself up and coil itself into a chromosome. The DNA wraps around histones and becomes chromatin where it will further coil and become thicker into chromosome. The coiling of DNA material saves space and therefore able to fit in the nucleus of the cell. 9) Give an example of something a scientist can do with extracted DNA. Scientists with the extracted DNA can come up with a lot of new ideas. With DNA extracted from a living organism, scientist will be able to learn how DNA is coded in the subject. Scientists will also be able to study heredity and the treatment to certain illnesses or diseases. Extraction of DNA from humans can also be used in identification of true paternity and maternity. Other than that, DNA once extracted can also be modified or re-engineered into a better manner to bring improvements into a plant or an animal. 10) Describe at least two procedures you followed to make sure you completed your investigation in a safe manner. -The first procedure I followed to make sure I complete my investigation in a safe manner is that I do not rub my eyes or make contact with any sensitive body part with my hands throughout the experiment. This is due to how the experiment involves substances such as detergent and salt in the DNA extraction solution, alcohol that can cause irritant to the body parts if exposed. -The second procedure I followed to make sure I complete my investigations in a safe manner is to wear proper attire before even conducting the experiment. Lab coat was worn before the experiment even starts. Long pants and cover shoes were also worn when conducting the experiment to ensure safety to the highest degree possible. 11) What ethical considerations are associated with this investigation? In what ways would the ethical considerations be different if you extracted DNA from animal cells? -If the extraction of DNA were to involved animal cells, it would be extracted from an animal. The process of extracting cell sample from the cell and extracting DNA from it should be done in the most humane way possible. The process of extracting DNA from cells from an animal should not involve killing the animal at any cost where the animals should be temporarily put into sleep. If killing the animal is needed in the extraction of DNA and the extraction of DNA itself is really much needed, then the killing of animal should be done in the most humane way ever possible. The animal who really needs to be killed for the good of mankind, should then be killed in the cleanest way so that to animal do not feel pain. Once the animal is killed for the good of mankind, every useful substance possible in the animal should be put into good use where it is not wasted at all in any way. This is due to how the animal sacrificed itself for mankind and the conductors of experiment should never waste it. -The animals used in the process of extraction of DNA should be treated nicely just like how any other animals are treated. There should not be animal cruelty in anyway possible before, during and after the process of DNA extraction. This is due to how animals do feel pain and if any processes of animal cruelty is involved, the animal itself would not feel good in any way possible. The animal involved in the experiment should be treated well just like how humans treat each other. -The ethical considerations involved in this investigation itself is the minimisation of resources used in the experiment. Plenty of fruits are used in the experiment and each of them are used wisely. Fruits are managed properly and throughout the experiment there were extremely little to no wastage of fruit. This is due to how fruits are also sources of nutrients that every living thing needs. Wasting the source of nutrient is wasting a generous offer from the nature when it can be consumed by every living thing possible on the planet and thus gaining nutrient from it. There are people around the world who struggles to find food and wasting it in this experiment is not a wise act. 12) Suggest at least one modification to the method and explain how it would improve the quality and/or accuracy of your results. -During the process of mixing the mashed fruit in the bag and the extraction fluid, the bag should be handled gently and not with force at any way. This is to reduce the bubble count when the mixture is being created due to how the extraction fluid contains detergent. This could improve the quality and the accuracy of the results obtained in the end of the experiment. -Another modification that can be done to the experiment to further improve the accuracy of the result is through the repetition of filtering of the fruit mixture. In the experiment procedure, the fruit mixture is filtered only once where is should be filtered not only once but instead more than that to filter out unwanted substances and therefore making the chromosome more visible. 13) Outline at least one addition or extension to this activity that would allow you to gather new information compared to that obtained by this activity. -An electron microscope should have been used in the experiment when the results are collected. This is due to how after the experiment the only result visible is the white precipitate layer on top of the solution. If a microscope is used in the experiment and used to observe the white precipitate layer after obtaining the results, the conductors of the experiment would be able to see DNA in a subatomic level. The conductors of the experiment would be able to see the actual chromatin of the cell used in the experiment and this further allows the conductors of the experiment to gather new information. Conclusion The result of the experiment is a positive one where the aim of the experiment has been met. The DNA of the fruits were extracted successfully with extremely little to no failure.