L.2 MINERAL SALTS IN ORGANISMS

INTRODUCTION:

Today in lab time, we made an experiment with bones and some mollusks. We know that the bones are very strong and that depends on how much of the mineral calcium carbonate contain. We have learned that when we combine this substance an acetic acid is produced a reaction that the carbon dioxide is liberated. But in few days we only see the collagen of the bones. The goal of this practice has been identify mineral salts in organisms and understand the function of inorganic biomolecules in skeletal structures of organisms. Our initial hypothesis was that the bones would be made more flexible.

MATERIALS: 
For this practice we needed:

- Some mollusks, shells (clams, mussels...)
- Dried, cleaned chicken or lamb bones
- Eggs
- Distilled Water
- Acetic acid
- Vinegar
- 2 x 600 mL Beaker
- 2x 200 mL Beaker
- Clock glass

PROCEDURE:

CHICKEN OR LAMB BONES:
First of all, with carefully clean and cut the meat from the chicken thin bone as possible, and we examine the flexibility of the bone. With our fingers we were trying to bend. Then we catch one bone and we have measured in the metallic balance. Subsequently, we take a beaker and mix the acid acetic with vinegar.  Then we introduce the bones and drop them in acid acetic solution. We put a clock glass on the top of the beaker to protect the solution. And now we have to wait 24 to 48 hours to see what happens.



MOLLUSKS SHELLS:
In this process we have to catch another beaker and put the same acid acetic solution. Then we just put inside the mollusks or eggs shells and we can observe that bubbles appear gradually. The acid acetic is dissolving the shells.



RESULTS AND CONCLUSIONS:

We have observed, that during this process, the bones has lost stiffness and has become more flexible. This is due to the dissolution of vinegar and acetic acid, which the bones dissolves calcium phosphate and calcium carbonate. Through the process of calcification of collagen fibers, while going slowly losing rigidity. In what refers to the mollusks and shells, these have only the inorganic matter that the acetic acid and vinegar have been dissolve. This process of dissolution of minerals in organisms, begins when the acetic acid begins to dissolve the shell and this shows in the form of carbon dioxide bubbles, until they gradually disintegrated up as i explained before, living inorganic matter.


QUESTIONS:

1.- Write the reaction that takes place when the acid acetic reacts with the calcium carbonate.
When calcium carbonate reacts with acetic acid, calcium acetate (Ca(CH3COOH)2) and CO2 are produced.

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 we can see bubbles, and this bubbles are carbon dioxide and collagen.

3.- What is happening to the bone after some days of soaking it in acetic acid? why is the bone flexible now?
Now is flexible because the bone loose collagen and calcium carbonate.

4.- So what is the function of the calcium carbonate in the skeletal structures?
The calcium carbonate gives rigidity and strength.

5.- Increases in carbon dioxide to the atmosphere from the burning fossil fuels and deforestation threaten to change the chemistry of the seas. Evidence suggest that this increase in atmospheric carbon dioxide is lowering the pH of the oceans in a process called ocean acidification. How can acidification effects corals reefs?
Acidification, difficult to completely prevent marine organisms such as corals to form their calcium carbonate structures, an essential component of their shells. acidification affect corals as CO2 emissions continue to grow at the current rate, ocean pH will fall to the lowest level and that would produce massive extinction of corals.