L5. CARBOHYDRATES

OBJECTIVES:


1. Identify different sugars
2. Understantand the relation between structures and some propeties. 

MATERIAL:

• test tubes
• glucose
• maltose
• sacarose
• lactosa
• starch
• beaker
• bunsen burner
• pipette
• spatula
• lugol
• water destilled
• test-tube rake
• wire gauze

PROCEDURES:

LUGOL	FEHLING
5mL H2O IN A TEST TUBE	2mL H2O
ADD SACCHARIDE	2mL FEHLING A
OBSERVE	2mL FEHLING B
2 DROPS OF LUGOL	TEST TUBE IN A BOLING WATER BATH

RESULTS:

	GLUCOSE	MALTOSE	SUCROSE	LACTOSE	STARCH
SWEET	YES	YES	YES	YES	NO
SOLUBILITY	YES	YES	YES	YES	NO
LUGOL	NEGATIVE	NEGATIVE	NEGATIVE	NEGATIVE	POSITIVE
FEHLING	POSITIVE	POSITIVE	POSITIVE	POSITIVE	NEGATIVE
MONO/DI/POLI	MONO	DI	DI	DI	POLI

L4.PH

OBJECTIVES:
1. Knowing view the pH
2. Measure different acideces

MATERIAL:

• Distilled Water 

• Lemon 

• Test tubs 

• ph measure

PROCEDURES:

We cut the lemon in half. We squeeze the two pieces to get juice.Take the pipette. When we have the tubes with all quantities mixed, add the paper measuring the pH to see which number has each mixture. 

RESULTS:

Test tubs	H2O (mL)	LEMON (mL)	PH
1	5	1	3
2	4	2	3
3	3	3	3
4	0	6	3

QUESTIONS:
1. Which is the dependent variable? The pH
2. Which is the independent variable? The lemon
3. Which is the control?

4. Which pH do you think are in blood? And gastric juice? The blood problably is 7 pH because is neutral, and gastric juice is 1 because we have all the acid here.

L3. OSMOSIS

OBJECTIVES:
1. Know about the osmosis phenomena
2. Understand the process of osmosis in plasmatic membranes

MATERIAL:

• Egg

• Potato 

• NaCl

• Distilled water

• Acetic Acid (Vinegar)

• Spatula 

• 600mL Beaker

• 3 Watch glass

• Knife

PROCEDURES:

Egg:

1. Take a 600mL beaker and put inside the egg.

2. 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, measure and weigh the egg. Record the dimensions of each egg in a table.

Potato:

1. Lay out three watch glass.

2. Slice the potato in three parts lengthwise.

3. Place each slice onto a watch glass and make a hole in the middle of each slice. NOTE: the hole does not have to cross the slice!

4. In the first slice hole, don’t put anything. The second fill it with NaCl and the third with distilled water.

5. Left this preparation 30 minutes and make note of what is happening




RESULTS:

QUESTIONS:

Egg experiment:

1. What is happening when the shells are soaking of acetic acid?

2. Write the results of de dimensions and weigh of the egg before and after immersing it in distilled water. Write and draw a simple diagram of the water direction.

Potato experiment:

3. Explain the results of this experiment.

4. Why have we left the first slice without any treatment (salt or distilled water)?


5. Which are the dependent and independent variables? 

L2. MINERAL SALTS IN ORGANISMS

OBJECTIVES:


1. Identify mineral salts in organisms
2. Understand the function of inorganic biomolecules in skeletal structures of organisms

MATERIAL:

• Acetic Acid
• Chicken bones
• Mollusks
• Baker 

PROCEDURES:

Chicken bones

1. Carefully clean and cut ad much of the meat away from the chicken thin bone as possible.
2. Examine the flexibility of the bone by trying to bend it with your fingers.
3. Take a beaker and make and acid acetic solution or add vinegar.
4. Take the chicken bones and drop them in the acid acetic solution (vinegar) that you have made.
5. tLeave it 24 hours and see what happens to the bone.
6. Write the results in your lab worksheet.

Mollusks shells

1. Take another beaker and make the same acid acetic solution.
2. Put inside some shells and make note of what is happening.
3. Write the observations in your lab worksheet.

RESULTS:

Chicken bones

The bones are more flexibility because of the lack of calcium.

Mollusks shells

The mollusks have desintegrated

QUESTIONS:

1. Write the reaction that takes place when the acid acetic reacts with the calcium carbonate. Calcium carbonate react with acetic acid: CaCO₃ + 2CH₃COOH → Ca(CH₃COO)₂ + H₂O + CO₂ 
2.  What is happening when the shells are soaking of acetic acid? What are the bubbles that you can see? when the shells are soaking the acetic acid it make bubbles. This bubbles are CO2.
3. What is happening to the bone after some days of soaking it in acetic acid? Why is the bone flexible now?  the bones are more flexible when dissolved the acetic acid because the bone is mainly made of calcium salts that are responsible for the hardness of the bones. When subjected to the action of vinegar (acetic acid), a chemical and much bone calcium vinegar reaction will go towards forming another substance called calcium acetate, losing in this way hardness, and becomes flexible.
4. So, what is the function of the calcium carbonate in the skeletal structures? the funcion is give rigidity on the bones
5. Increases in carbon dioxide to the atmosphere from the burning fossil fuels 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? Cuando el CO2 de la atmósfera se disuelve en el agua, el pH baja ligeramente y se producen cambios químicos de los carbonatos. Esto a su vez hace más difícil formar sus conchas y esqueletos a una serie de animales marinos