Strawberry Dna Extraction Lab Answers

Activity 1 - Deoxyribonucleic acid Extraction

Nosotros will extract Dna from fruit to investigate how it looks and feels. This procedure is like to what scientists have to practise before they can employ the information contained in this Deoxyribonucleic acid. This information tin can be used to improve crops then that they are more than resistant to affliction, insect invasion or changes in climate.


Figure one	Figure ii

Objectives

Extract Deoxyribonucleic acid from plant cells
Empathize the general construction of cells

Teacher preparation for experiment

Time Required: ~ 20 minutes

*Night before put 95% ethanol in freezer*

Make extraction solution (see beneath).
Outset water heating to threescore°C.
Ready ice-water bathroom.
Prepare fruit pieces.
Gather materials for each student group every bit listed below.

Extraction Solution

Materials (100 ml)

ten ml of clear shampoo (Suave daily clarifying shampoo)
ane.5 g of table common salt
Distilled H_twoO

Procedure (change amount depending on the size of a class)

Mix xc ml of distilled water and 1.5 grand of salt.
Add together shampoo until solution volume is 100 ml. Stir slowly to avoid foaming of the shampoo.
Measure 20 ml of solution into 1L zipper numberless (1 per student pair).

Student Activity - DNA Extraction

Materials

Time required: ~ 45 minutes

one-liter Zipper purse (ane per pupil pair) with 20 ml of extraction buffer
Skinned and freshly cut kiwi fruit (each fruit cutting into 12 pieces) or one large strawberry (each provides ~thirty chiliad per student pair)
500 ml beaker (class)
Hot water plate with beaker or saucepan of water prepare at a constant lx°C (class)
Cheese cloth (cut to fit over small chalice)
Tape
Large libation with ice water bath (class)
Ice cold 95% ethanol (2 ml per educatee pair)
ane small test tube (one per student pair)
i woods applicator (one per student pair)
Transfer pipettes

Procedures

Add kiwi/strawberry fruit into extraction solution in the zipper bag. Close bag and squeeze out air.
Trounce the kiwi/strawberry thoroughly for 5 minutes. CAREFUL don't break the bag!
Place the bags into the hot water bath for about 10-15 minutes, making sure the fruit solution is fully beneath the h2o line. Occasionally shake the bag to evenly distribute the rut.
Move the "mashed" bags of kiwi/strawberry fruit solution into the ice bath for 1 minute. Remove and carefully mix the kiwi/strawberry fruit solution again. Repeat this process 5 times.
Tape the cheese cloth over the beakers. Filter the fruit mixture through the cheese cloth. Combine solutions from all student groups at this point. Let the solution drain 5 minutes.
Using the large transfer pipettes, aliquot approximately two ml of the kiwi/strawberry fruit solution into a test tube, ane for each pair of students.
Add approximately ii ml of water ice-cold ethanol to each tube past dropping it slowly downwardly the side of the test tube, allowing information technology to rest on height of the kiwi/strawberry fruit mixture. Practice not agitate the solution.
Let the solution sit for two minutes without agonizing it. The Deoxyribonucleic acid will appear as transparent, slimy, white mucus which tin be spooled up with the wood applicator stick.

Prodcedure Questions

Why do we "vanquish" the kiwi/strawberry fruit?
Why do we use shampoo?
What does the common salt do?
Why do we need to cool the mixture?
What does the common cold ethanol do?
Why can't we utilise room temperature ethanol?

Word Questions

To extract DNA from cells, what must you isolate it from in the case of a plant such as strawberry?
What steps did we use to extract the DNA?
What is DNA used for when it is extracted?

Answers to Procedure Questions

Why practice nosotros "crush" the kiwi/strawberry fruit? Crushing the kiwi/strawberry fruit physically breaks apart the prison cell walls.
Why do nosotros apply shampoo? After the prison cell walls take been disrupted during mechanical mashing of the fruit, the detergent in the shampoo disrupts the prison cell and nuclear membranes of each cell to release the Deoxyribonucleic acid. It does this by dissolving lipids and proteins that hold the membranes together.
What does the salt exercise? The salt neutralizes the negative charges on the Deoxyribonucleic acid and thus enables the Deoxyribonucleic acid strands to stick together. It also causes proteins and carbohydrates to precipitate.
Why do nosotros need to absurd the mixture? DNases or restriction enzymes that destroy Deoxyribonucleic acid are present in the cell's cytoplasm. They are in that location to protect the prison cell from invasion by viruses. Once the nuclear membrane is destroyed by the lather, the DNA is at present susceptible to the DNases and will quickly be degraded. Still, these enzymes are temperature sensitive and cooling the solution slows down the process of degradation.
What does the cold ethanol do? Everything except the DNA will dissolve in ethanol. The ethanol pulls h2o from the Dna molecule and so that it then collapses in on itself and precipitates. The DNA will become visible as white mucous strands that tin can be spooled with the wooden applicator stick.
Why can't we utilize room temperature ethanol? The colder the ethanol is the greater the amount of DNA that is precipitated. (You could try having some of the students use room temperature ethanol and see if the amount of DNA they can spool is the same or less than that for the groups using the ice-cold ethanol.)

Discussion Questions and Answers

To extract DNA from cells, what must y'all isolate it from in the example of a found such as strawberry? All the other parts of the jail cell - the cell wall, prison cell membrane, nuclear membrane, mitochondria, vacuoles, endoplasmic reticulum, Golgi appliance, lysosomes, etc.
What steps did we use to extract the DNA? Showtime we broke apart the cell walls by physically squishing the fruit. The chemic (detergent) process broke down the cell walls, cell membranes and nuclear membranes. The fruit mixture was cooled to stop the DNases released from the cytoplasm from destroying the prison cell's DNA. The mixture was filtered to separate out the large jail cell parts that are not needed. The DNA was then precipitated through chemic means (the ethanol).
What is DNA used for when it is extracted? Dna can be used for the identification of people involved in crimes, to help make up one's mind parentage of people and besides of plants and animals, and to check for genetic defects. For example, the Dna of these kiwi/strawberry fruits tin be compared to other samples to determine if 1 of them has been altered in some mode, such as changes that might be made to brand a ingather more nutritious. Deoxyribonucleic acid from 1 organism carrying a gene that codes for a specific trait might as well be used for transformation. The section of DNA containing this particular factor tin exist inserted into a different organism so that the altered organism now has a specific trait that information technology did non previously deport.

(Adapted from http://world wide web.ctbiobus.org)

References

www.accessexcellence.org
www.biotech.iastate.edu
www.biology.arizona.edu

The following website provides a protocol for extracting your own Deoxyribonucleic acid! http://world wide web.nature.ca/genome/05/051/pdfs/DNAextract_e.pdf