14/15 course
L2. Mineral salts in organisms
Objectives:
1. Identify mineral salts in
organisms.
2. Understand the function of
inorganic biomolecules in
skeletal structures of
organisms.
MATERIALS:
• Some molluscs’ shells (clams,
mussels, etc.)
What makes bones Strong?
Even though bones are very light,
bones are placed in the glass with
they are also very strong. However,
acetic acid, this acid dissolve the
• Water
how strong they are depends on
calcium carbonate so that only
• Acetic Acid
how much of the mineral calcium
collagen is left.
• Tongs
carbonate they contain.
• Dried, cleaned chicken or
lamb bones
• 2 x 600 mL Beaker
• Clock glass
During foetal development, strong
Eggs and bones contain calcium
fibbers of collagen protein form a
carbonate (CaCO3). When calcium
matrix for bones. The matrix is
carbonate and acetic acid combine, a
shaped like bones but is very
chemical reaction takes place and
flexible. The matrix solidifies by a
carbon dioxide (CO2) is released.
process called calcification. During
We can see this effect observing
this process, calcium phosphate or
some bubbles in de solution.
hydroxyapatite is deposited in the
But bones are made also of soft
material called collagen. When
fibbers of collagen and gives the
bones strength and rigidity.
Lorem
L2:
mineral
Ipsumsalts in organisms
PROCEDURE:
Chicken or lambs 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 or lamb bones and drop them in the acid acetic solution that you have made.
5. Leave it 24 hours and see what happens to the bone. Put a clock glass at the top of the beaker to protect
de solution.
6. Remove the bones from the vinegar with a tong and soak them with water.
7. 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.
L2: MINERAL SALTS IN ORGANISMS
1st EVALUATION
QUESTIONS:
1. Write the reaction that takes place when the acid acetic reacts with the calcium carbonate.
2. What is happening when the shells are soaking of acetic acid? What are the bubbles that you can
see?
3. What is happening to the bone after some days of soaking it in acetic acid? Why is the bone
flexible now?
4. So, what is the function of the calcium carbonate in the skeletal structures?
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?
Prof. Dra Laura Martínez
[email protected]
www.cepciencies.cat
Centre d estudis Prat
Roger de Llúria, 97
08009 Barcelona, 93 215 58 52