FISH DISSECTION

In our last practice of the year the students brought different fishes and they made their dissection. At the beginning, they showed some respect but they quickly get used to their dead new friend and managed to identify all its organs. Don´t miss the pics and the video.

Observing our DNA

In this practice we'll be able to observe our DNA from our mouth cells.

 Would you like to know a little about DNA?

 Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions for the development and function of living things. All known cellular life and some viruses contain DNA.

The main role of DNA in the cell is the storage of information.

 It is often compared to a blueprint, since it contains the instructions to construct other components of the cell, such as proteins and RNA molecules.

The DNA segments that carry genetic information are called genes, but other DNA sequences have structural purposes, or are involved in regulating the expression of genetic information.

 In eukaryotes such as animals and plants, DNA is stored inside the cell nucleus, while in prokaryotes such as bacteria and archaea, the DNA is in the cell's cytoplasm.

See how we have done!



 

Starch

Starch is a carbohydrate consisting of a large number of glucose units joined by glycosidic bonds. This polysaccharide is produced by most green plants as an energy store. It is the most common carbohydrate in human diets and is contained in large amounts in staple foods such as potatoes, wheat, maize (corn), rice...

We are using a iodine test to detect the presence of starch in some food as it combines with iodine to form a black purple complex.

 Here you are what we did and the conclusions we make!

Iodine Sublimation

Sublimation  is the change of a soldid substance directly to a vapor without passing through the liquid state. The term is also used to describe the reverse process of the gas changing directly to the solid again upon cooling. An exemple of sublimation is seen when iodine, on being heated, changes from a dark solid to a purplish vapor that condenses directly to a cristalline solid upon a striking a cool surface. In this way pure crystatls of iodine are prepared.

CHROMATOGRAPHY

This week we´ve been working in a new practice: Chromatography.
This technique can be used to separate mixtures of coloured compounds.
We used chard and spinach leaves to separate their pigments. We've cut the leaves in small pieces,mash them, mix them with alcohol and sand and filter it... Do you want to Know more about this practice? Watch this video!



 

Lab life!

Measuring pH of common substances

Depending on the pH substances can be acidic or basic. Traditionally those solutions that tasted sour were said to be acidic and solutions that tasted bitter and were slippery to touch were said to be basic. We are going to use indicators to know if a substance is acid o alkali. An indicator contains a chemical that changes color when it comes in contact with acids or bases. For example litmus and universal indicator papers turn red in strong acids and blue in strong bases. let's see how we are doing!!