domingo, 7 de junio de 2015

Conclusion and Evaluation

Conclusion

It is clearly seen that the amount of time the organ has been dead has a great impact among the DNA it produces. DNA is no longer produced after death, mainly because cells die and cannot keep dividing itselfs. Moreover, there is surprisingly a great amount of DNA extracted, taking into consideration that the organs we used weighed approximately 100 to 125 grams. In week 1 we extracted about 25 grams, which is more or less 25% of the whole mass of the organ. This reveals the big amount of DNA which is present in each organ.
Logically, as time goes on, cells start to decompose and destroy, as a consequence, DNA decomposes with them. We know that DNA is saved in the nucleus in eukaryotic cells, but after cell death, the decomposition begins at the nucleus, and, therefore, in the strands of DNA.
There is a big distinction between DNA produced after the organs being dead in weeks 2 and 3. After this, the decrease of the amount of DNA starts to become lower and lower, probably because there is a larger amount of bacteria which keep the organ surrounded and not affected by climatological changes.
Also, there are less bacteria in the organ in week 1 than in week 5 because they are much less time exposed to the outside world. The bacteria do not just protect the organ and eat it, but also they produce DNA, which can alter our experiment.
This experiment could be used in the future for therapeutic cloning, for example, because with strands of DNA we could create whole new organs which would be very useful to other people.  Furthermore, we could create new proteins and hormones changing the order of nucleotides. This would use a different aminoacid than an expected, so, a new protein.
Some materials have a specific function, for example, parsley is necessary because it softens the solution. Alcohol and dish washer are essential. The dish washer breaks down the molecules of DNA, separating them from the rest of cells. The alcohol being poured slowly down the sides makes a solution which is completely heterogeneous, and, according to a principle in physics, the thing that has more volume, in this case, DNA, will come out and try to mix with the lighter part, the alcohol. This makes us have DNA which can easily be taken out of the beaker now.
The video shows the experiment done, and now it is corrected.

Evaluation

Weak points

  • Possibly we did not extract as much DNA as it was possible, mainly because as we stirred the organ, we were supposed to only use the liquid part, the solid part we did not have to use. Therefore, more DNA which could be found there could be extracted.
  • We stirred the testicles for a longer amount of time than estimated because there was very little liquid and the quantity of DNA would be clearly reduced.
  • In some cases we poured more amount of a certain material than needed, since we saw that perhaps some substances could still be found in the beaker.
  • It is possible that stirring the solution too hard may have affected the molecules of DNA, and consequently, not have produced as much as it should.
  • The main weak point is that we cannot know if the DNA came from the organ which we had or from the bacteria which surrounded it. Due to the fact that DNA is universal for all living beings, DNA from a bacteria is equal to DNA from an animal. Therefore, the bacteria are a variable that we cannot control and that have a very big impact on our experiment.
  • We could not know when the animal had been killed, because the butcher did not know, so the time we give is very relative.

Improvements

  • We should have spent more time trying to make all the substances pass through in order to have a larger amount of liquid.
  • We should have cut the organ several times so that it would be much easier to stir, and avoid the breaking of the molecules.
  • Putting the organ in water an hour before the experiment took place was an improvement that we should have thought about earlier because it would have saved us a lot of time.
  • Making sure that putting the exact amount of liquid to not make any mistakes is a good improvement because it will make our experiment quicker, as there will be a less amount of things to clean.
  • To improve the quantity of DNA, and also to reduce the chances of possible errors, we could have mixed the mixture more gently. Furthermore, the mixture has got to be completely homogeneous, which did not completely be.
  • Comparing our results after having done the complete research would be helpful because we would make sure there were no silly mistakes which could affect our complete experiment.
  • To improve the quality of the experiment, before starting to stir the organs, we could have cleaned them to reduce the amount of bacteria in the organs, and therefore, more “pure” DNA.
  • We could have put in a better way the DNA in the microscope because some parts were thicker than others and it was hard to see through the microscope.

Limitations

  • One of the main problems we had was that the mixer was broken by other students, so we spent two weeks not being able of doing the experiment. However, we met at Pablo’s house and did it there because his mother did not let him bring another mixer to school.
  • We have had less time in some lessons because we had to go and buy the organs, which took a while. In the meantime, the other person prepared the materials.
  • The laboratory was, at times, very crowded and we could not do the experiment correctly because there was not enough amount of space.

 

sábado, 6 de junio de 2015

Results:

Results:

Video of the experiment:


https://lh5.googleusercontent.com/_N-jGlcK_kust1OCdjmaX0Dv0aV1fT9SPBMTTy-7_mLywSKBlXvR7PiXB0GVfImU1SaHDAsPHYJbaGiYOsfklLWA0b-ikgpUeeKJwmUB7Boh-LF0IiNusFRxqthFfdul-gj_QTo

From the first experiment we extracted 23,03 grams of DNA. The testicle of the pig had been dead 10 days ago. After, in the second experiment, 15,55 grams of DNA were extracted from a heart of a pig. It had been dead for 21 days.

For the third trimester we will try to look at the DNA through the microscope.

https://lh6.googleusercontent.com/jIQVqiQukhkDauYg1VOdJXKr90apJluHt1RJWsCSqwlER9FDXbLEjsBoy5ggnyPSiAfjdwSFBwnkuUI4kjiGl6mgKfbUGxFaR4UZ6GRQtoFETlscq-QrdXu3uM4SdqTGe7ahaSU
As we can observe,...

https://lh5.googleusercontent.com/a8DtiR6E0wcKV5ult5G1lQbqGeCybOabCh8rtDQ3VI1FKID8SxAO0oNToj_63VGMPWnyXwZ0xjLUlK5B7vKi9gm-L2rBcMKByfnLXTkl-jjfSs8y_bHlMUvN4xDwYwIdT3AF95E

Table of Results:

1º WEEK
2º WEEK
3º WEEK
4º WEEK
5º WEEK
Amount of DNA extracted from the testicles
25, 07 grams
23, 03 grams
15, 55 grams
11, 35 grams
9, 12 grams


martes, 18 de noviembre de 2014

Source evaluation

ScienceDaily,. (2015). DNA. Retrieved 4 March 2015, from http://www.sciencedaily.com/articles/d/dna.htm

This document is clearly an official document of an english newspaper that is written by scientific people and also this newspaper is updated every day so that is a proof that is official.

The author of this website is wikipedia, this scientific newspaper was buyed by wikipedia in 2011 and as we think they bought this newspaper because it was very productive and also this website only speaks about one important theme that is Science. 

As we can see this text is addressed to an audience of a broad knowledge in the field of science. Specifically it addresses to an age of eleventh grade more or less. This is shown  in the way that the author get expressed and also the vocabulary that in this case he is using.

This text is written in english so we observe that the author could be for another country but, he could want that all the people understand his observation about DNA and also what he thinks. 

In our opinion we think that this website is for giving to the public a great knowledge about DNA and  specially in animals. And also this could help many people to make an investigation about this, as in our case are doing. 

This page shows some features of unreliability because it  comes from Wikipedia, however, as I said before this page can be only uploaded by  files that are well appreciated by the audience.

Genetics Home Reference,. (2014). What is DNA?. Retrieved 5 November 2014, from http://ghr.nlm.nih.gov/handbook/basics/dna

This is clearly an official document, a web page of the U.S. National Library of Medicine.
The authors of this web page are the members of the National Institution of Health, so they know what they are writing about and we can trust the information they are communicating to us through the web page.

Due to the information that is on the website, we can say that it is written for people who have a minimum of knowledge on the subject because it uses specific words and advance vocabulary for the explanations. In any case, although the content has specific vocabulary, it is very well explained and therefore can be understood easily.

This web page explains all about genetics and we will focus on the DNA part to find information about it.

We can say that this source is reliable because it is written by people who understand about the subject because they are experts in health and work in the National institution of Health.

We can also see that the website is constantly being revised by individual members. In this way, the information that appears is always updated. The latest update of the website occurred on 12 August 2014.

Background Information

Background Information:

DNA is formed by two chains which are polynucleotidic which form a double helix. The sugar in
the nucleotides always are in the deoxiribose group, and the bases must be A, G, C and T. This
model was described by Watson and Crick in 1953. Both chains are joined by their bases
(which are joined by hydrogen bonds) and are parallel and anticomplementary.

Complementarity means that if one chain is found, somewhere, the A base, in the same place
but in the other chain the T base will be found. Therefore, in a double strand of DNA, A=T and
G=C. This happens every time except for mutations. So, we can figure out the second strand by
having the first one, and vice versa.
DNA has two fundamental functions on human beings:

1) The DNA in the chromosomes is the material by which genes are formed. It contais the 
information necessary that allows the synthesis of every protein in a living being. This 
genetic information which was inherited from our progenitors must be decodified in 
order to be used by the cell, and this process is realized in tho stages:

- Transcription of the genetic information contained in a gene, which allows the cell to 
copy information from the other chains of DNA and copy them which is RNA.

- Translation of the message from the sequence of RNA bases corresponding to a gene, 
it is realized in the ribosomes, which convert this message into a sequence of amino 
acids from a certain protein. 

2) Replication: each molecule of DNA may originate several replicas of itself. Each cell, 
before its division, copies its genes so that its successors contain the same genetic 
dotation as itself.  Therefore, the genetic information will be transmitted from every 
generation.

(ScienceDaily, 2015)

Variables

Independent variable: The time that the organs are died
How are we going to mesure this? This is going to be mesured by freezing those organs and keep them for  few hours inside that fridge , then we are going to extract the DNA and then mesure by watching it with a microscope. This is going to be repeated with other organs of animal. 

Dependent variable: The quantity of DNA that those organs produce will be the dependent variable because it depends on the time the organs still produce DNA. We will see the amount of DNA the organ produces through the experiment and then through a microscope. We will measure the amount of DNA without alcohol in grams.

Constant variable: The same quantity that we are using with all the different types of  materials. We keep the organs the same in the same environment.

Variables we cannot control: We can't control the time the organs have been dead before we buy them, and we can't know where they have been before their death.

miércoles, 5 de noviembre de 2014

Method

      1) We speak with the butcher

      2) Once we have spoken with the butcher, we investigate without the organs
   
      3) We buy the organs

      4) We put the organs in the fridge covered with a plastic bag to avoid smelling it

      5) Each week we cut a piece a of an organ and we see if we can obtain the DNA

      6) We obtain the DNA through the process stated before

      7) We do the same with every organ until there is nothing left or no DNA is produced

      8) We write down the results
    
      9) We do tables (one per organ)

    10) We do graphs (one per organ)

    11) We compare the results

    12) We figure out which organs produce more DNA than others for longer

    13) We make our own conclusions of why some organs produce more DNA for longer than others

    14) We put it all in the same document so it is organized

miércoles, 22 de octubre de 2014

Diary

MEMBERS
LUIS
PABLO
DAVID
WEEK 1
IVESTIGATES WITH THE INFORMATION GIVEN BY PABLO
SPEAKS WITH THE BUTCHER
X
WEEK 2
X
DOES CRITERION B (INTRODUCTION)
DOES CRITERION A (METHOD)
WEEK 3
DOES CRITERION C
X
INVESTIGATES WITH THE INFORMATION GIVEN BY PABLO
WEEK 4
X
DOES CRITERION D
X


*X : This means that in the corresponding week he doesn´t have to work 

3rd Evaluation: 

29/4/15: Al empezar la clase  hemos ido a la carnicería (David y Luis) a comprar 2 testiculos de toro, mientras Pablo se ha quedado en el laboratorio preparando los materiales. Cuando llegamos a clase comenzamos con el experimento con todos los m En una hora y cuarto de clase logramos terminar el experimento; hemos pesado la cantidad extraída y lo hemos mirado en el microscopio. 

6/5/15: En esta semana hemos tenido un problema ya que teníamos todo preparado para repetir el experimento y  la batidora dejo de funcionar. Por lo tanto, sin la batidora no hemos podido realizar el experimento ya que no podíamos triturar el testículo. Consecuentemente, hemos aprovechado para avanzar el trabajo escrito, ordenando los datos obtenidos las pasadas semanas en una tabla de resultados

13/5/15: