PROTEIN IDENTIFICATION

BIURET'S TEST:
Biuret's test is a chemical test used concentration.
For detecting the presence of peptide bonds. Polypeptides as proteins, are chains of amino acids link together by peptide bonds.
A peptide bond can be broken by hydrolysis (the adding water). In organisms, protein molecules called enzymes facilitate the process.

OBJECTIVES:
1. Identify peptide bonds.
2. Compare protein concentration in different foods.

PROCEDURE: 
DILUTE THE PROTEIN 
1. Add 100ml of distilled water to each 250ml beaker. Lebel them with M(milk), EW (egg white), EY (yolk), P (potato) and RM (rice milk)
2. Separate the egg white and the yolk in another beaker.
3. Smash the potato in a mortar and add some amount of the smashed potato to the P beaker.

PREPARE THE SAMPLES:
4. Add 10ml of a dispersion of each food (M, RM, EY, EW and P) to the indicate beaker. Calculate the final concentration. All the groups will use the same dispersion from the beakers.
5. Prepare 6 test tubes (cleand and dry) and lebel (M, RM, EY, EW and P). Add 2ml of the every food dilution of each beaker.

6. Add 2ml of 20% NaOH dissolution. 

7. Shake gently and add 5 drops of CuCO4 in each tube. Allow the mixture 5 minutes. 

8. Note any colout change. Remember that proteins will turn solution pink or purple. 

9. Compare the test tubes. 

---------> CuCO4











----------> NaOH

Observations and results: 

RESULTS: 

Positive: M, EW( more proteins that the EY) and EY (have a lot of lipids)

Negative: P, RM 

- The concentration of proteins change the colour. 

- The sodium hydroxide change the pH (basic) 

- The copper change the colour. 

- The food that has more proteins is the milk. 

SAPONIFICATION

Introduction: 
In this experiment we used: NaOH, olive oil and Sudan III.
With this different elements we created soap.

Objective:
- To do the saponification
- To make soap

Procedure: 
1- We need to take a test tube rack
2- Take one test tube and put 2ml of Na OH.
3- Put 2ml of olive oil.
4- You need to mix with a sterring rot
5- Put the test tube in a beaker with water in the bunsen burner (10 minutes)
6- You will see the soap (solid part and yellow)

Results:

Olive oil---Triolein 

SECOND PART:

Introduction:

In this part of the experiment we used: milk and Sudan III to see if the colour change to red. 

Objective: 

- To know if there are presence of lipids 

Procedure:

- In a test tube you need to put a little bit of milk. 

- Put some drops of Sudan III

- Observe what is happening 

Observations: 

We can see that when whe put the Sudan III the colour of the milk change to red, that means that there are a presence of lipids. 

LIPIDS PROPERTIES

Introduction:
Lipids are heterogenous group of compounds synthesized by organisms that are present in all biological tissues. 
These compounds are characterized as natural substances that do not mix with water but dissolve in organic solvents. 
There are several classes of lipids, including: fatty acids, waxes, triacylglycerols, phospholipids, trepens ans steroids. 

Objectives: 
- Test the solubility of lipids. 
- Identify lipids in liquids compounds. 
- Understand what are an emulsion and the effect of detergents 

Procedure: 
Solubility of some lipids:
1- Clean and dry three test tubes. Label as W (water), ethanol (E) and PE (ether)
2- Add 3 drops of oleic acid to 3 small test tubes. 
3- Add 1 ml of water in the first test tube (W)
4- Add 1 ml of ethanol in the second test tube (E). 
5- Add 1 ml of petroleum ether in the third test tube (PE). 
6- Shake carefully each test tube and record solubility and observations in your worksheet. 

Conclusion: The water in the first test tube create a monolayer, and the ethanol and the ether dissolve. 

Lipids identification: 
Translucent mark:
7- Cut two pieces (10x10) of cellulose paper. 
8- Put 1 drop of water in the first squared piece. You will see a translucent spot, wait for a while and observe what is happening. 
9. Put 1 drop of olive oil in the second squared piece of cellulose paper. You will see a translucent spot. Wait for a while and observe what is happening. Ha the spot disappeared? Why? 

Sudan III dye: 
Sudan III is a red fat-soluble dye that is utilitzed in the identification of the presence of lipids, triglycerides and lipoproteins in liquids. 

10- Take the W test tube of the first experiment and add 2 drops of Sudan III 
11- Prepare four test tubes: 3 with milk with different fat content (M1, M2, M3) and soda (S). Add two drops of Sudan III and observe the results.  

Results: 
We can see that the colour of the oil change (red) because it has fatty acids. The water doesn't change the colour because doesn't have fats.

PERMANENT EMULSION: 
12- Take a 250ml beaker and put 100ml of water. 
13- Add 1ml of olive oil. With a glass rod stir the mixture vigorously and let it stand for a few minutes. 
14- Make note of what is happening. 
15- Add 2 drops of soap and stir the mixture again. Let it stand for a few minutes and notice the differences between both mixtures.

Results: 
Water with oil = We can see that when we stir the water with oil, the oil never dissolve, the micelles come together. 
Water with oil and soap = The micelles are not together because there are soap, and create a membrane that don't let the micelles come together. (We can see in the image). 

STARCH

Introduction:
In this experiment we will use a bunsen burner, tripod stand, wire gauze, 250 cm3 beaker, boiling tube, forceps, test tube holder, leaf to be tested, 90% ethanol and iodine or potassium iodine solution to see in different food if they have starch or not. We have the leaf after been exposed to sunlight and food that we eat many times.

Objectives:
- Identify the presence of starch in leaves.
- Relate the presence of starch with photosynthesis.
- Identify the presence of starch in some food.

Procedure:
- Remove a green leaf from a plant that has been exposed to sunlight for few hours.
- Half-fill a 250cm3 beaker with water. Heat the water until it boils. Keep the water at boiling point.
- Use the forceps to place the leaf in the boiling water. Boil for 2 minutes.
- Turn off the Bunsen Burner.
- Place boiled leaf in a boiling tube containing 90% ethanol.
- Place the boiling tube in hot water and boil for 10 minutes or until the leaf decolourizes. (It may be necessary to replace the ethanol).
- Gently remove the leaf and wash with a fine trickle of cold tap water.
- Spread the leaf evenly on a white tile.
-Add a few drops of iodine/potassium iodine solution to the leaf and note any observations.

Questions:
1- Which is the origin of the starch that you can see in the leaf?Answer: From the glucose that was synthesized the starch 2- Complete the reaction and write the name of this process:Answer: CO₂ + H₂Oà C₆ H₁₂ O₆ + O₂     
3- Explain the significance of boiling the leaf in water. 
Answer: Lose the turgent condition. 
4- Explain the significance of boiling the leaf in ethanol. 
Answer: To lose the color (chlorophyll dissapears) 
5- Explain the significance of rinsing the leaf in water
Answer: Beacuse the lugol is not soluble with ethanol. 


SECOND PART: 
Material:
- Frankfurt
- Jam
- Potato
- Three watch glass
- Knife
-Iodine

Objective: 
To detect the preseure of starch in different foods.


Procedure:
- Put each food in different watch glass.
- Open the frankfurt in the middle.
- Cut an small slice of potato.
- Put an small piece of jam.
- Use the dropper tu put iodine.
- Compare the potato with the rest.
Lugol stains starch (specially)











Observations:
We can see that in the photo the potato have a different colout of the rest, this is because the potato have a lot of starch.

FEHLING'S TEST: REDUCING SUGARS

INTRODUCTION: 
Fehling's solution is a chemical test used to differentitate between reducing and non-reducing sugars. This test is based on the reaction of a functional group of sugar molecules with Fehling's reagent.
Fehling's reagent has to separate solutions: Fehling's A and Fehling's B.
Fehling's A: is a blue aqueous solution of copper (II) sulphate.
Fehling's B: clear and colourless solution of potassium sodium tartrate and sodium hydroxide.

OBJECTIVES: 
- Identify reducing sugars.
- Comprehend redox reactions.
- Understand the relation between structure and reducing ability of some sugars.

PROCEDURE: 
1. Take 5 test tubes and label: G, M, S, L, ST
2. Put 2mL of distilled water inside each tube.
3. With different spatulas put a small amount of each sugar. Dissolve the sugar.
4. Add 2mL of Fehling's A solution and then Fehling's B.
5. Place each test-tube in a boiling water bath (250 mL beaker on a hotplate stirrer).
6. Observe what is happening.

Results: We can see that different test tubes have an orange colour.

Starch Hydrolysis: 
 7- Place 2mL of 1% starch in a test tube and add 0,5 mL of 3M HCL. Mix and place this mixture                in a boiling water bath for 10 minutes.
8- After 10 minutes, remove the tube from the water bath and let it cool. Neutralize this solution with 1M NaOH and mix well.
9- Transfer 10 drops of this solution to a small test tube.
10- Add 1mL of Fehling's A solution and 1mL of Feghling's B.
11- Heat for a few minutes in a boiling water bath.
12- Record your observations. Compare the results of this test with your results for                                       unhydrolyzed starch in the step 1 of this                                                                                                   experiment.

You can see that in the result the colour is blue/green that means that is neutralized.

SACCHARIDES PROPERTIES

Introduction: 
Saccharides are organic molecules consisting of C, H and O atoms. Usually the empirical formula is Cn H2n On. Are divided into three groups: Monosaccharides, Oligosaccharides, Polysaccharides.

Objectives: 
1- Identify different sugars from its properties.
2- Differentiate mono and disaccharides.
3- Understand the relation between structure and some proporties.

Procedure:
In the first part of the experiment we are going to test some physical properties of the saccharides you have in the lab: flavour, crystal structure and colour.
-FLAVOUR: put small amount of each saccharide in your hand and taste it, Is it sweet or not sweet?
-CRYSTALS: Observe a small amount of each saccharide on a clock glass under magnification.
-COLOUR: white, transparent or creamy.


TO TEST SOLUBILITY:
- Clean and dry 5 test tubes and label them: G, M, L, SU, S
-Put 5mL of water in each test tube.
-With the aid of a spatula, put a small amount of each saccharide inside the labelled test tube and test if they are soluble or insoluble.
- Observe is each saccharide forms a mixture called dissolution or a colloidal suspension.
- Finally, add 2 drops of Lugol's iodine to each test tube and test if the reaction is positive or negative. Lugol's is a solution of elemental iodine (I) and potassium iodine (KI) in water that is ise to test a saccharide. The reaction is positive when iodine reacts by turning from yellow to a purple, dark-blue/black colour.

 
Results: We can see the different test tubes we put lugol's iodine , and one is in different colour, is the  the starch (positive).

Egg's shell

INTRODUCTION: 
Osmosis is a vital process in biological systems, as biological membranes are semipermeable. Water molecules travel through the plasma membrane in order to equilibrate the intra and extra cellular concentrations.

OBJECTIVES:
--> Know about the osmosis phenomena.
--> Understand the process of osmosis in plasmatic membranes.

PROCEDURE:
Egg: This experiment will be divided in two days.
FIRST DAY:
- Take a 600mL beaker and put inside the egg.
- Cover the egg with vinegar and make note of what's happening.

Once the egg's shell is removed and the egg is rinsed dry and clean, mesure and weigh the egg. Record the dimensions of each egg in a table.

- Clean the beaker and put the egg inside again.
- Cover it with distilled water. Make note of the volume of solution inside the beaker.

SECOND DAY: 
- Left the egg one day in the distilled water. After about a day, carefully remove the egg using a spoon. Rinse the egg with water and let it dry.

OBSERVATIONS:
We can see that the shell of the egg is more soft because of the water that are inside, if we touch the egg, the egg brekas because of the pressure of the water.

Results:
- Inside the egg we have hypertonic.
-Out the egg we have hypotonic (the water were inside the egg)

pH

Introduction: 
The pH is a mesure of the acidity or basicity of a solution. Solutions with a pH less than 7 are said to be acidic and solutions with a pH greater than 7 are basic or alkaline. Pure water (distilled water) has a pH close to 7, neutral. (pH=-log [H+])

Objectives: 
1. Mesure different pH values of organic and inorganic solutions.
2. Prove different methods of measuring pH.

Procedure: 
1- Squeeze the lemon and tomato in two clock glasses.
2- Take a piece of indicator paper and place one end of it into the solution. Leave for at least 20 seconds.
3- Remove the indicator paper and compare its colour with the appropriate colour chart.
4- Repeat points 1 to 2 with as many others solutions as you are provided with,
5- Record your results in a result table in your worksheet.

How does concentration affect pH?
6- Prepare the test tube rack with 5 test tubes cleaned with distilled water. Mark the tubes with the labels: A, A1, A2, A3 and B.
7- Add 10 ml of Lemon juice to tubes A and B.
8- Take the A tube and put 5ml of its lemon juice to the test tube A1 (5ml of distilled water).
9- Take the A1 tube and put 2,5 ml of its lemon juice to tube A2 (7,5ml distilled water).
10- Take the A2 tube and put 1,2 ml of its lemon juice to tube A3 (8,7ml distilled water)
11- Add distilled water to each test tub until it has the same volume as test tube B (10 ml)
12- Calculate the concentration of each test tube with the formula.

Test          Volum of           Total           Concentration           pH
B              5 + 5                    10 ml           0,5                              2,70
A1            2,5+7,2                10 ml           0,25                            2,56
A2            1,2 +8,7               10 ml           0,13                            3,08
A3            1,2+8,8                10 ml           0,12                            3,08
A              10 ml                   10 ml           1                                 2,81

























QUESTIONS:
1. Which of the solutions gave and acid pH? Lemon, tomato, vinagre, coca-cola, HCL and wine.
2. Which of the solutions was alkaline? Na OH, soap solution.
3. Which of the solutions were neutral? Did you expect these results? Explain. Milk,  souy milk. Yes but the milk I though that was an alkaline.
4- How does a pH of 3 differ from PH of 4 in terms of H+ concentrations? HCL, H3 have more H+ than the H4, have 10 more H+.
5-
      a) Which is the dependent variable? Is the Ph
      b) Which is the independent variable? The lemon juice concentration.
      c) Which is the problem that we want to solve? Can the juice lemon concentration variate the          Ph3?
      d) Which is the control of the experiment? Is the B, have 100% lemon juice.
      e) Write the results and conclusions: Independent Variable
6- Which pH do you think that gastric juices might have? why? Do you think that intestinal pH has the same pH? why? Acid, because we need to combine with the food and remove. Fisrt we have basic acid but then change to acid.
7- Which pH do you think that blood might have? Why? Neutral (7,2)
8- What is acid rain? Which are the consequences in the ecosystems and how is its formation pattern? Is rain in Barcelona acid or alkaline? Destruction of forest, brake the rocks. We have acid or alkaline.

Osmosis

Introduction: 
Osmosis is the spontaneous movement of solvent molecules through a semipermeable membrane into a region of higher solute concentration (hypertonic), in the direction that tends to equalize the solute concentrations on the two sides. 

Objectives: 
- Know about the osmosis phenomena. 
- Understand the process of osmosis in plasmatic membranes.

Procedure: (Potato)
- Take the potato and cut it in three picies and put it every picie in a watch glass. 
- Take the spatula and make an small hole in the middle of each picie of potato. 

 1- Control of the experiment 
 2- Salt treatment (put salt inside the hole) and leave it. 
 3- Put distilled water treatment (leave it 20 min) 

Observations: 
In the first pass (control of the experiment) the potato is dry. 
In the second pass (salt treatment) the potato is with more water. 
In the third pass (distilled water) the potato absorbs the water. 


--> In the salt treatment we have the hypertonic medium 
--> In the distilled water we have the hypotonic medium 

Mineral Salts In Organisms

Introduction: 
- Even though bones are very light, they are also very strong, how strong they are depends on how much of mineral calcium carbonate they contain. Eggs ans bones contain calcium carbonate (CaCO3). 
In this experiment will be create the bones more flexible. 

Objectives: 
- Identify mineral salts in organisms.
- Understand the function of inorganic biomolecules in skeletal structures of organisms.

Procedure: 

Bones:
- Cut ad much of the meat away from the chicken thin bone as possible.
- Examine the flexibility of the bone.
- We put the bones inside the beaker.
- We took a beaker and we put: 200ml of water and 200ml of acid acetic or vinegar.
- We cover the beaker to protect the solution and we need to leave it 24 hores to know what happens to the bone.



Observations of bones: 
The bone is more flexible because lose the ridigity with the acid or vinagre.


Shells: 
- We took another beaker and put water and calcium carbonate.
- We put inside some shells.
- We saw a lot of bubbles.







Obervations of the shells:
 - Three hours later we saw that the shells were floating, and the meaning of this is that the shells are less dense than the water.









REACTION:
HCL + CaCo3------> CO2 + CaCl2


QUESTIONS: 
1. Write the reaction that takes place when the acid acetic reacts with the calcium carbonate.
Answer: bubbles
2. What is happening the shells are soaking of acetic acid? What are the bubbles you can see?
Answer: bubbles are formed. The bubbles are carbon dioxide.
3. What is happening to the bone after some days of soaking it in acetic acid? Why is the bone flexible now?
Answer: the bone is more flexible, and they leave it the ridigity .
4. So, what is the function of the calium carbonate in the skeletal structures?
Answer: Rigidity.
5. Increases in carbon dioxide to the atmosphere from the burning fossil and deforestation threaten to change the chemistry of the seas. Evidence suggests that this increase in atmospheric carbon dioxide is lowering the pH of the oceans in a process called ocean acidification. How can acidification affects corals reefs?
Answer: The reefs coral will be dissolve because the pH will be reduce of the corals.