Lab1: Macromolecules Flashcards
What are the four important macromolecules?
-lipids
-proteins
-carbohydrates (sugar)
-Nucleic acids
What is the name of the test for protein?
Xanthoproteic test
What is the principle of the xanthoproteic test?
Test if their is prescence of alkali by adding ammonium hydroxyde and removing nitric acid
What tells us that it is a positive test for the proteins?
The solution turn to a yellow or orange colour and if their is presence of alkali turn into deep orange
What is the main substance where searching for in the protein test and what result would it indicate?
Présence of aromatic amino acids indicate a yellow color
Xanthoproteic test is a biochemical test for the detection of…
Amino acids
What type of group of amino acids the Xanthoproteic test is searching for?
Aromatic amino acids
What is the principle type of aromatic amino acid that we will found in this experiment?
Tyrosine
What are the two main test for lipids?
-brown paper test
-on top of water
What would be a positive result for the brown paper test?
The brown paper became “see trough” translucent
Why would lipids be floating on the layer of water?
Because they are hydrophobic
Is lipid the only macromolecules that can float on water?
Yes
Will the fat spot remain translucent?
Yes
What is call the test for simple sugar?
Benedict’s test
What would be an example of simple sugar?
Glucose
What would be an example of simple sugar?
Glucose
What is the main idea of the Benedict’s test?
To heat the sample with the basic solution containing cupric copper
In the reaction of the Benedict’s test in what the cuppric copper is reduced?
Into red cuprous oxide
What would be a positive result for the Benedict’s test?
The color of the solution changes to green to yellow to orange — depends on the amount of glucose
What would be an example of a complex sugar?
Starch
What consist the test for complex sugar?
To put a few drop of dilute iodine in the unknown solution
What would be a positive result for the complex sugar test?
Change of color from yellow to blue-black color
Why do we observe those color in the complex sugar positive result?
Because the iodine becomes embedded in the centre of a coil of glucose monomers. — electrons are forced into a configuration — absorb certain wavelengths of light, resulting in the blue/black color
How does the chemical structure of lipids explain the property of floating on water?
-Because lipids are hydrophobic because they consist mainly of fatty acids who are hydrophobic
-Have a lower density than water
-Arrangement in bilayer (like in the cell membrane)
Why is the brown paper opaque before you add the oil?
Because of the way light interacts with the cellulose fiber and the air gaps between them. Cellulose has a high refractive index, so when the light it the brown paper it diffuses in many directions and that make the paper opaque.
Would you expect the proportion of protein/lipids to be higher or lower in High dentist lipoprotein(HDL)?
Higher because it has a greater protein content that supports their function of transporting cholesterol whereas LDL has a higher lipid content
Based on the structure of the amino acids, why do you know that theses amino acids are HYDROPHOBIC?
Because of their side chain, that are non-polar aromatic rings and because they have carbon-hydrogen bond who are also non-polar so they can’t form hydrogen bonds with water
