ACTIVITAT ENZIMÀTICA DE LA CATALASA

• Introducció:

Valore de forma quantitativa l'activitat enzimàtica de la Catalasa del fetge de pollastre. Dividirem la pràctica en dues parts. En la primera observarem la diferència d'activitat de la catalasa en diferents teixits animals i vegetals. Per aquesta part utilitzarem la patata, tomàquet, pastanaga, cor i el fetge de pollastre. en la segona part veurem la influència de determinats factors en l'activitat enzimàtica.

La catalasa és un enzim present ens els peroxisomes de les cèl·lules animals i vegetals que s'encerrega d'eliminar l'aigua oxigenada que es forma en algunes reacciones del metabolisme. La reacció químia és la següent:

2 H₂O₂ (l) → 2 H₂O (l) + O₂ (g)

• Material:

-Diferents teixits animals.

-Patata, tomàquet i pastanaga.

-Tubs d'assaig de coll ample.

-Termòmetre.

-Aigua oxigenada 3%.

-Pinces.

-Tisores.

-Bisturí.

• Protocol:

Experiment 1: Quin teixit presenta més activitat de la catalasa?

-Tallarem 2 trossos la patata, el tomàquet i pastanaga que pesin més o menys el mateix (1 cm3)

-També tallarem un tros de fetge i cor de la mateixa mida i pes.

-Ho posem en cinc tubs amb 5ml d'aigua destil·lada i 2ml d'aigua oxigenada. I mesurarem l'alçada en mm de les bombolles.

-Patata: 0,7gr, Tomàquet: 0,9, Pastanaga: 0,9, Fetge: 0,7 i Cor: 1gr.

• Preguntes:

Variable dependent i independent? Dependent: alçada de les bombolles i Independent: els diferents teixits.

Problemes què es vol investigar? Quin teixit presenta més activitat de la catalasa?

Explicació dels resultats: La catalasa presenta més activitat en els teixits animals.

Experiment 2: Com afecten diferents factors en l'activitat de la catalasa?

1er Tub: tros de teixit animal a temperatura ambient (T=19º) (pes: 1gr)

2n Tub: tros de teixit animal amb 10ml d'HCl al 10% (pes=0,89 gr)

3er Tub: tros de teixit animal congelat(T=3º) (pes: 0,7 gr)

4at Tub: Tros de teixit animal bullit (pes: 0,5 gr)

5è Tub: tros teixits submergit en una dissolució saturada de NaCl (pes: 0,7gr)

       *Amb 5ml d'aigua destil·lada i 2ml d'aigua oxigenada.

• Preguntes:

-Variable dependent i independent? Dependent: alçada de les bombolles, Independent: diferents tractaments.

-Problema què es vol investigar? Com afecten els diferents factos en l'activitat de la catalasa?

-Explicació dels resultats: El teixit que ha estat tractat amb NaCl presenta una activitat de la catalasa.

• Quina és la funció de la catalasa en els teixits animals i vegetals? On es troba aquest enzim?

Catalitza la descomposició del peròxid d'hidrogen (H202) en oxigen i aigua. A nivell cel·lular es localitza en les mitocòndries i els peroxisomes, excepte en els eritròcits, on es troba en el citosol.

• Per què quan ens fem una ferida ens posem aigua oxigenada?

Perquè en el cas que hi hagui bacteris, tan aeròbics com anaeròbics, els elimina evitant una possible infecció.

L21: The chloroplast and the photosynthesis.

• Material:

-Algae 

-600 ml beaker

-Test tube

-Funnel

-Tap water 

-Light source

-Ruler

 

• Procedure:

1. First we assigned the different distances to do the experiment and compare the results to each group.

2. We took the 600 ml beaker and placed 7 g of an algae under a clear funnel inside the beaker (the wide end goes over the algae like in the image). The funnel was raised off the bottom on pieces of blue-tack to allow unhampered diffusion of CO2 to Elodea. 

3.We didn't have sodium bicarbonate so we filled the beaker with tap water, the algae and the funnel should be completely under the water.

4. Then we filled a test tube with tap water and placed the thumb over the end of the test tube. We turned the test tube upside down taking care that no air enters and no water comes out and we put this test tube over the end of the funnel (the skinny part)

5. We marked the level of the water on the surface of the test tube with a marker pen.

6. Each group placed the preapartion close to a light source, each group placed the preparation in a different distance 5, 10, 20 and 25 cm, and one with no light source.

7. We also measured the temperature.

8. Finally we left this preparation for and hour and a half. After this time we measured the difference of gas accumulation on the top of the test tube.

 

• Questions:

1. Identify the dependent and the independent variable of this experiment.
Dependent: gas production, Independent: distance (intensity of the light)
 
2.Using the data from your results prepare a graph and describe what happened to the amount of gas in the test tube.

3.How much gas was producted in the test tube after one hour? And an hour and a half?
I  put the results in the graph.
 
4.Write the photosynthesis equation. Explain each part of the equation. Which subtances are produced by photosynthesis. Which gas is produced that we need in order to live? Plants take in carbon dioxide by diffusion through their stomata. Light energy enters the plant via leaves and water and nutrients enter through roots. The plant is then able to make glucose and oxygen. The glucose moves from the leaves to the plant and the oxygen diffuses out of the leaves. The gas that we need in order to live is oxygen.

 

L20: Mitosis in an onion root.

• Material: microscope slide, coverslip, dropper, needles emmanegades, watch glass, beaker, fine tweezers, lancet, encenador and dad filter.
• Chemicals: aigua destil·lada, aigua corrent, orceïna A i orceïna B.
• Natural products: onions.
• Procedure:

1. Keeps several days a bulb onion on a glass full of water, so that the lower part of bulb where the roots emerge, in contact with water. To hold the onions can be three sticks nailed to utility bulb.
2. When the roots have grown about three centimeters, cut with scissors and place them end four millimeters in a crystal clock with two millimeters orceïina A.
   Then, heat it with the flame of a lighter until steam appears tenuous. It must ensure that during this process the temperature exceeds 60 ° C at any time.
   To check this, we constantly have to remove the glass clock above the flame and put it over on the back of the hand, which in no case should notice a burning sensation.
3. With fine tweezers, place one of the pieces of root on a slide and add a few drops of orceine B with dropper.
4. With the lancet, cut the two millimeters final piece of root and retira'n the rest. Put it on the coverslip and three or four strips of papaya filter. Then make it a slight pressure with the thumb, starting gently and then a little harder, trying not to break the coverslip in order to extend the cells.
5. Observe it with a microscope 600 increase (or preferably more). As luck you have, you will see cells in different phases of mitotic division.

L15: Animal cells vs. Plant cells

• Objectives:

1. Identify the major components of cells.
2. Differetiate between animal and plants cells.
3. Measure dimensions of the entire cell and the nucleus.

Staining: iodine.



 

 

Staining: Methylene blue.

L19: Cells Organelles.



Tomato cromoplast (400x)





Chloroplasts of Vallisneria sp



 

Carrot Cromoplast (100X)

Red Cabage Cloroplast (400X)

Red Cabage Stoma (1000X)

Red Cabage (100X)



L16: Life in a drop of water.

400X

It is a unicellular being, eukaryotic flagellated.

L17:Gram Staining.

• Objectives:

1. Differentive yogurt bacteria.
2. Relative the staining procedure with the structure of the cells. 
   
   
   MAGNIFICATIONS: 400X