PROTEIN DENATURATION

INTRODUCTION:
Denaturation is a process in which proteins or nucleic acids lose the quaternary, tertiary and secondary structure that is present in their native state.

OBJECTIVE:
1.Study de relation between the structure and the function of proteins
2.Understand how temperature, pH and salinity affect to the protein structure.

MATERIALS:
-2x250mL beaker
-4 test tube
-10mL Pipet
-Knife
-Glass marking pen
-Potato
-Distilled water
-Hydrogen Peroxide
-NaCl
-HCl

CATALASE ACTIVITY:
Catalase is a common enzyme found in nerly all-living organisms exposed to oxygen. It catalyzes the composition of hydrogen peroxide to water and oxygen. It is a very important enzyme in protecting the cell from oxidative damage and preventing the accumulation of hydrogen peroxide.
In this experiment we are going to test the catalase activity in different environment situations. We are going to mesure the rate of enzyme activity under various conditions, such as different pH values and temperature. We will mesure catalase activity by observing the oxygen gas bubble when water is destroyed.
Prepare 30mL of water 10% in beaker with a pipet
Prepare 30mL of HCl 10% in beaker
Prepare 30mL of NaCl 50% in beaker
Peel a fresh potato tuber and cut the tissue in five cubes of 1cm3
Weight them and equale the mass
Label the test tubes
Immerse 10 minutes your piece of potato inside HCl beaker
Immerse 10 minutes another piece of potato inside NaOH beaker
Boil another piece of potato
With a mortal, mash up the third piece of potato
Prepare 5 test tubes as indicated below
Add 5mL of watwe 10% in each test tube

TUBE	TREATMENT
1	Raw potato
2	Boiled potato
3	Potato with HCl treatment
4	Potato with NaCl treatment
5	Mashed up potato

The independent variable is the test tube and the dependent variable is the bubble weight. In this photo we can see this:

QUESTIONS:

1. How did the temperature of the potato affect the activity of catalase?  

Temperature denaturate the catalase. 

2. How did the change of the pH of the potato affect the activity of catalase?

The change of the Ph denaturate the catalase. 

3. In wich potato treatment was catalase the most active? Why do you think this was?

In the mashed potato,  because we had broken the cells. 

4. An experiment was performed to test the effect of temperature and pH on the activity of Enzyme X. The following data was collected during the experiment: 

a) What is the optimum pH of enzyme X? 8 (maximum activity)

b) What is the optimum temperature of enzyme X? 20 (maximum activity)

c) Why do you think enzyme X has low activity at a pH of 10? Because has been denatured 

DNA EXTRACTION

INTRODUCTION:
Desoxyribonucleics acid is a nucleic acid that encodes the genetic instructions udes in the development and functioning of all know living organisms and many viruses.

MATERIALS: 

-1L Efety gogglesrlenmeyer flisk

-100mL beaker
-10mL graduated cylinder
-Small funnel
-Glass stirring rod
-10mL Pipet
-Knife
-Safety goggles
-Cheesecloth
-Kiwi
-Banana
-Pineapple juice
-Distilled water
-90% ethanol ice-cold
-7mL DNA buffer
-50 mL dish soap
-15g NaCl
-900mL tap water

PROCEDURE:

Put the ethanol in the freezer-you will need it really cold later!
Prepare the buffer in a 0'5L beaker:
-450mL of a tap water
-25mL of dish soap
-7g NaCl. Stir the mixture.







1.Peel the kiwi and chop it to small piece. Place the pieces of the kiwi in one 600mL beaker and smash with a fork until it becomes a juice puree.
2.Add 8mL of buffer to the beaker.
3.Mash the kiwi puree carefully for 3 minutes without creating many bubbles.
4.Filter the mixture: put funnel on top of the gradduated cylinder. Place the cheesecloth on top of the funnel.






5.Add beaker contain  carefully on top of the cheesecloth to fill the graduated cylinder. The juice will drain through the cheesecloth but the chucks of kiwi will not pass throught into the graduated cylinder.
6.Add the pineapple juice to the green juice. This step will help us to obtain a purer solution of DNA. Pineapple juice contains an ezyme that breaks down proteins.
7.Tilt the graduated cylinder and pour in an equal amount of ethanol with an automatic pipet. Put the ehanol through the sides of the graduated cylinder very carrefully. You will need about equal volumes of DNA solutions to ethanol.
8.Place the graduated cylinder so that it is eye level. Using the stirring rod, collect DNA at the boundary of ethanol and kiwi juice. Don't stir the kiwi juice, only stir in the above ethanol layer.
9.The DNAprecipitate looks like long . white and thin fibers.
10.Gently remove the stirring rod and examine what the DNA looks like.

(Roger's photo blog)

QUESTIONS:
1.Like a gelatine, colour white.
2.To brake the cells. It is located in the cell wall
3.We add salt to brake the cells and soap to clean the proteins.
4.It is a good methond to catch it bacause the DNA goes to ethanol.

Determinació: llet, caseïna, altres proteïnes, midó i glúcids reductors i presència de lípids

DETERMINACIÓ DE LA COMPOSICIÓ DE LA LLET:
La llet conté vitamines (tiamina, riboflavina, àcid pantotènic i vitamines A, D i K), minerals (calci, potassi, sodi, fòsfor i metalls en petites quantitats), proeïnes, glúcids i lípids. Els únics elements importants que no te són ferro i vitamina C.
L'objectiu de la pràtica és identificar tots aquests components.

DETERMINACIÓ DE LA CASEÏNA:
La caseïna és una proteïna conjugada del tipus fosfoproteïna que se separa de la llet per acidificació i forma una massa blanca. Les fosfoproteïnes són un grup de proteïnes que es troben químicament unides a àcid fosfòric, en el cas de la caseïna aquests grups fòsfor es troben units als aminoàcids serina i treonina. La caseïna representa entre 77 i el 82% de les proteïnes presents a la llet. Aquesta proteïna presenta una baixa solubilitat a pH 4,6. En la primera part del experiment aïllareu la caseïna.
1- Afegiu 200ml de llet en un vas de precipitats i escalfeu fins 40 graus aproximadament.
2- Traieu-lo del foc i afegiu gota a gota àcid acètic (1ml d'àcid acètic glacial en 10 ml d'aigua destil.lada) amb un comptagotes. Agiteu amb una vareta de vidre fins que acabi de precipitar tota la caseïna.

3- Separeu la caseïna amb ajuda d'una espàtula i poseu-la en un vidre de rellotge. Poseu-lo a assecar en la placa calenta.
4- Afegir immediatament en el líquid que us ha quedat 4 gr de carbonat de calci en pols. Agiteu al llarg d'uns minuts i guardeu-lo per la següent part. Això és el sèrum de la llet.
5- Quan la caseïna hagi perdut l'aigua calculeu el percentatge de caseïna aïllada sabent que la densitat de la llet és 1,03 g/ml.

206g-------27'3g          

100.........X             X=13'15       

DETERMINACIÓ D'ALTRES PROTEÏNES:

1-Determineu la presència d'altres proteïnes en l'extracte (sèrum) de la pràctica anterior mitjançant la prova de Biuret. 

2-Per poder realitzar la pràctica heu d'utilitzar:

- 2ml de sèrum 

- 2ml d'hidròxid de sodi

- 5 gotes de sulfat de coure 

DETERMINACIÓ DE MIDÓ I GLÚCIDS REDUCTORS:

1-Determineu si la llet conté midó en el producte que heu extret (sèrum) de la pràctica anterior. 

2-Determinar la presència de glúcids reductors.

3-Per realitzar la pràctica heu d'utilitzar:

- Petita quantitat de sèrum + lugol 

- Sudan III 

DETERMINACIÓ DE LA PRESÈNCIA DE LÍPIDS:

1-Determineu la presència de lípids de la llet en un tub d'assaig amb 2ml de llet. 

2-Afegiu 1ml d'HCL al 50% al tub d'assaig anterior i escalfeu suaument, anoteu els resultats que observeu. 

3-Proveu-lo també amb el sèrum de la llet de la pràctica 1. 

4-Utilitzeu 2ml fehling A/B.

(Roger's photo blog)

PROVA	PROVA UTILITZADA	RESULTAT
pH de la llet	Tires indicadores de pH	7pH
Quantitat (gr) caseïna en 100	Àcid acètic i desnaturalització	13’25%
Prèsencia d’altres proteïnes	Biuret	Positiu
Midó	Lugol	Negatiu
Greixos	Sudan III	Positiu: té greixos
Glúcids reductors	Fehling	Té poder reductor perquè hi ha lactosa

RED ONION OSMOSIS

INTRODUCTION:
In this experiment we can see the osmosis process of the red onion.

OBJECTIVES:
We see what happens when we put distilled water and salt water in a piece of red onion.

PROCESURE:
Phase1: Normal Cells/ Dry mount
-Carefully slice away the colored layer of cells from the red onion. This should only be the thin purple layer. Trim to get a piece about this actual size.
-Place the thin, purple onion layer on a dry microscope slide shinny side up- don't put on water or cover slip yet
-Scan the entire onion tissue on low power to find and center the most purple area and focus. Set the microscope to medium power and focus the view.
-Take a picture.




Phase2: Salt water environment/ Wet mount 
Now that you have observed the layer of normal cells which are the subject of this lab, make a wet mount  using 2 or 3 drops of salt water solution on the onion tissue then install cover slip.
-Watch the cells for epproximately 2-3minutes or longer as you again survey the entire onion tissue on low power. You should see changes within many of the cells initially near the perimeter of the onion tissue. As time passes all or most of the cells should become affected by the salt water. Find some cells that have noticeably been affected and observe them under medium power.



Phase3: Distilled water environment/ Wet mount
-After you have colored the diagram correctly above, you need to prepare for phase 3 of this lab by putting the entire salt water wet mount in the dish of tap water to rinse off the salt water from the slide, cover slip ADN onion tissue layer. Dry the slide and cover-slip then gently dab the onion tissue dry.
-Make a wet mount of the onion tissue you just rinsed using 2 or 3 drops of distilled water on the onion tissue then install cover slip. Watch the cells for approximately 2-3 minutes or longer as you again survey the entire onion tissue on low power. You should see changes within many of the cells initially near the perimeter of the onion tissue. As the time passes all or most of the cells should become affected by the distilled water. Find some cells that have noticeably been affected by the distilled water and observe them under medium power.
QUESTIONS:
1.When the salt solution was added to the onion cells, where was the greater concentration (most pure) of water? How do know this?
The greater concentration where inside, because outside is the salt solution.
 2.In the winter, grass often dies near the roads that have been covered in salt to remove the ice. Using what you have learned in this experiment, what do you think is the reason the grass dies?
The cells leaft water.
3.Which kind of transport does water follow across the membrane?
The passive transport.

ANIMALS CELLS vs PLANTS CELLS

MATERIALS:
-Toothpick
-2 slides
-2 covers slips
-Distilled water
-Methylene blue
-Iodine
-Onion
-Glycerine


OBJECTIVES:
1.Identify the major components of cells.
2.Differetiale between animal and plant cells.
3.Mesure dimensions of the entire cell and the nucleus

PROCEDURE:
Plant cell observation
1.Pour some distilled water into a watch glass
2.Peel off the leaf from half a piece of onion and using forceps, pull out a piece of transperent onion peel (epidermis) from the leaf.
3.Put the epiderms in the watch glass containing distilled water.
4.Take a few drops of iodine solution in a dropper and transfer into another watch glass.
5.Using a brush, transfer the peel into the watch glass containing the dye. Let this remain in the safranin solution for 30 seconds, so that the peel is stained.
6.Take the peel from the iodine solution and place it in the watch glass containing distilled water.
7.Take a few drops of glycerine in a dropper and pour 2-3 drops at the center of a dry glass slide
8.Using the brush, place the peel into the slide containing glycerine.
9.Take a cover slip and place it gently on the peel with the aid of a needle.
10.Remove the extra glycerine using cellulose paper.
11.View it in the microscope. 

HOW TO USE A MISCROSCOPE

There are diferents types of microscope:
-Light microscope: is the microscope that you have in school. The common magnifications are: 440X, 60X, 100X.
-Electron microscope: allow scientist to view a universe too small to be seen with a light microscope. Electron microscope don't use light, they use electrons. Threre are two types:
   ·Scanning electrons microscope: they scan surface.
   ·Transmission electron microscope: the electrons are passed throught very thin samples.

Parts of the microscope: ocular lens, arm, body tube, light, base, diaphragm, objectives, revolving nosepiece, stage clips, coarse adjustment knob, stage and fine adjustment know.

The magnifications:

	Magnification	Ocular lens	TOTAL: magnifications
SCANNING	4	15	60
LOW POWER	10	15	150
HIGH POWER	60	15	900