Activitat de la Catalasa

Introcucció:

• Valorarem l'activitat de la catalasa de forma quantitativa del fetge del pollastre. Dividirem l'activitat en dues parts: En la primera observarem la diferència d'activitat de la catalasa en diferents teixits animals i vegetals. Utilitzarem patata, pastanaga, tomaquet, fetge de pollastre i cor. En la segona part veurem la influència de determinats factors en l'activitat enzimàtica.
• La catalasa és un enzim present en els peroxisomes de les cèl.lules animals i vegetals que s'encarrega de eliminar H2O2 que es formen en alguner reaccions del metabolisme. La reacció química és: 

                                        H2O2 ---------------> 2H2O + O2

Material:

1. Fetge i cor
2. Patata, pastanaga, tomàquet
3. Tub d'assaig
4. Termòmetre
5. Aigua oxigenada 3%
6. Pinces
7. Bisturí

Protocol:

    Experiment 1:

• Tallem un troç de tomàquet, un de pastanaga i un de patata en forme de cub (1x1 cm tots 3)
• Tallem un troç de fetge i de cor de la mateixa mida que els teixits vegetals
• Ho posem en 5 tubs (cada teixit en un tub diferent)
• A cada tub hi posem 5 mL d'aigua destilada 
• A cada tub posarem 2 mL d'aigua oxigenada, i marcarem l'alçada fin on arriben les bombolles. Mesurarem l'alçada en mm

    Preguntes experiment 1:

Variable dependent i independent:

             Dependent: Alçada de les bombolles

             Independent: diferents teixits

Problema que es vol investigar:

             Quin teixit presenta més activitat de la catalasa?

Explicació dels resultats:

             Els animals presenten més activitat enzimàtica que els vegetals.

Resultats:

     Experiment 2:

• Agafarem el teixit del fetge i el posarem en 5 tubs d'assaig sota condicions diferents
  1er tub: tros de teixit a temperatura ambient (a 19 graus 1 g)
  2n tub: tros de fetge amb 10 ml d'HCl al 10% (0,9 g)
  3er tub: fetge congelat (a 2 graus 1,2 g)
  4t tub: fetge bullit. (1g)
  5è tub: fetge submergit en una dissolucio saturada de NaCl (0,8 g)

Resultats:

P20. The chloroplast and the photosynthesis

INTRODUCTION:

We will investigate how it affects the distance of the light relative to a algae in her photosynthesi.

OBJECTIVES:

• Relate the light intensity with the photosynthesis process.
• Measure the rate of photosyntesis.
• Identify the products of the process and the variables that can affect it. 

MATERIALS:

• Algae 
• Beaker (600mL)
• Test tube
• Funnel
• Sodium bicarbonate solution (10%)
• Light source
• Metric Ruler

PROCEDURE:

1. Take a big beaker (you have to place a funnel inside)

2. Every group will place a spring of algae (underwater) under a clear funnel inside the beaker.     Place the wide end of the funnel over the algae as the image you have belw. The funnel is         raised off the bottom on pieces of blue-tack to allow unhampered diffusion of CO2 to Elodea. 

3. Fill the beaker with the sodium bicarbonate solution; the algae and the funnel should be             completely under the solution.

4. Fill a test tube with the solution. Place your thumb over the end of the test tube.Turn the test     tube upside down, taking care that no air enters.

5. Mark the level of solution on the surface of the test tube.

6. Place your preapartion close to a light source. Each group will place its preparation in a             different distance from the light source. 
    5cm, 10cm, 20cm, 25cm and one with no light source.

7. Measure the temperature.

8. Leave this preparation 1 hour and a half. After this time we measure the difference of gas accumulation on the top of the test tube. 

Conclusions and coments:

The comclusions are: 

P19. Organuls cells

                                                            red cabadge cloroplasts (400X)

                                                                 starch granules (100X)

                                                                  starch granules (40X)

                                                                  starch granules (1000X)

                                                       orange carrot cloroplasts (400X)

                                                                         stomata (400X)

                                                                         stomata (400X)

                                                                        cheek cells (400X)

                                                                         cloroplast (100X)

(400X)

P17. Gram staining

OBJECTIVES:

• Differentiate yogurt bacteria.
• Relate the staining procedure with the structure of the cells.

MATERIAL:

• 1 Slide
• 1 Cover slip
• Tongs
• Needle
• Gram stain: crystal violet, iodine and safranin.
• Descolorize reagent: ethanol 96%
• Microscope
• Yogurt

PROCEDURE:

   1. Prepare a heat-fixed sample of the bacteria to be stained.
   2. Cover the smear with crystal violet for an exposure of 1 min.
   3. Rinse with distilled water.
   4. Apply Iodine solution for 1 min.
   5. Rinse the sample with distilled water.
   6. Decolorize using ethanol. Drop by drop until the purple stops flowing. Wash immediately with          distilled water.
   7. Cover the sample with the safrain stain for an exposure time of 45 seconds.
   8. Rinse the sample with distilled water.
   9. Gently dry the slide with paper.

CONCLUSIONS:

P18. Life in a drop of water

In the video we see a unicellular eukaryote protozou flagel. This body moves through the water.

P16. Epidermis Cells

OBJECTIVES:

• Identify the shape of epidermis cells.
• Identify and explore the parts of a stoma.
• Measure dimensions of the entire cell and the stoma.

MATERIALS:

•  1 Slide
•  1 Cover slip
•  Distilled water
•  10% Salt water
•  Scissors
•  Needle

PROCEDURE:

Plant cells observation:

1. Cut the stalk of the leek.
2. In the place of the cut, pull out the transparent part of the epidermis and using forceps.
3. Using the brush, place the peel onto the slide containing a drop of tap water.
4. Take a cover slip and place it gently on the peel with the aid of a needle.
5. View it in the microscope.
6. Describe the change in the shape of the cells.
7. Draw a diagram with the parts of a stome: stoma,cell guards,epidermis cells.

Salt treatment:

1. Prepare a 10% of salt solution.
2. Put the salt with a dropper on the left part of the slide.
3. Place a piece of cellulose paper in the opposite part of the cover slip, and let the dissolution to go though your sample.

Conclusions and coments:

 

QUESTIONS:

1.        What is the major function of a cell membrane?

• Keep separate internal environment of the phospholipid layer and transport functions played by proteins. The combination of active transport and the passive transport endoplasmic make a selective barrier membrane that allows the cell differentiation medium.

2.      What is the major function of the cell wall?

• The cell wall protects the cell contents, and gives rigidity, works as a mediator in all relations of the cell with the environment and acts as a cellular compartment. In plants, defines the structure and provides support to the tissue and many more parts of the cell.

3.      How does salt affect the cells shape? And the stomes?

• Salt wrinkle cells and stomes (turgency)

P12. DNA EXTRACTION

INTRODUCTION:

• Desoxyribonucleic acid (DNA)  is a nucleic acid that encodes the genetic instructions used in the development and functioning of all known living organisms and many viruses.

• Nucleic acids are biopolymers formed by simple units called nucleotides. Each nucleotide is composed of a nitrogen-containing nuclease (G, T, C, A) as well as a monosaccharide (desoxyribose) and a phosphate group.

• These nucleotides are joined to one another in a chain by covalent bonds between the sugar of the nucleotide and the phosphate of the next.

• Most DNA molecules consist of two strands coiled around each other to form a double helix. The two strands run in opposite directions to each other and are therefore anti-parallel. Moreover the bases of the two opposite strands unit according to base pairing rules : A-T and G-C.

•  Within cells, DNA is organized into structures called chromosomes.

OBJECTIVES:

1. Study DNA structure
2. Understand the process of extracting DNA from a tissue.

MATERIALS:- 1L Erlenmeyer flask.- 100mL beaker.- 10mL graduated cylinder.- Small funnel.- Glass stirring rod.- 10mL pipet.- Knife.- Safety goggles.- Cheesecloth.- Kiwi.- Pineapple juice (1mL/5mL).- Distilled water.- 90% Ethanol ice-cold.- 7mL DNA buffer.- 50mL 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 0,5L beaker: Add 450mL of tap water, 25mL of dish soap and 7g NaCl. Stir the mixture.

1. Peel the kiwi and chop it to small pieces. Place the pieces of the kiwi in one 600mL beaker and smash with a fork until it becomes a juice pure.2. Add 8mL of buffer to the mortar. 3. Mash the kiwi puree carefully for 1 minute without creating many bubbles. 4. Filter the mixture: put the funnel on top of the graduated cylinder. Place the cheesecloth on top of the funnel.5. Add beaker contain carefully on top of cheesecloth to fill the graduated cylinder. The juice will drain through the cheesecloth but the chucks of kiwi will not pass through in to the graduated cylinder.6. Add the pineapple juice to the green juice ( you will need about 1mL of pineapple juice to 5mL of the green mixture DNA solution). This step will help us to obtain a purer solution of DNA . Pineapple juice contains an enzyme that breaks down the proteins.7. Tilt the graduated cylinder and pour in an equal amount of ethanol with an automatic pipet. Put the ethanol through the sides of the graduated cylinder very carefully. You will need about equal volumes of DNA solution to ethanol. 8. Place the graduated cylinder so that it is eye level. Using the stirring rod, collect DNA at the boundary of the ethanol and kiwi juice; only the stir in the above ethanol layer!9. The DNA precipitate looks like long, white and thin fibers.10. Gently remove the stirring rod and examine what the DNA looks like. 

QUESTIONS:1.- What did the DNA looks like?

• The DNA looks like white  and thin fibers.

2.- Why do you mash the kiwi? Where it's located inside the cells?

• The DNA is located in the nucleus and we mashed it to liberate it. 

3.- Explain what is the function of every compound of the buffer (soap and salt). 

• The salt can breaks the nucleus cell and we put soap to take away the proteins.

4.- DNA is soluble in water, but not in ethanol. What does this fact have to do with our method of extraction?

• We can see the DNA in the part of ethanol because, if we touch the water the DNA can dissolve.