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2nd HIGH SCHOOL BIOLOGY BLOG
CURIOSITIES ABOUT LIPIDS
Welcome to a new entry. After looking at the photo on the cover and reading the title, you will be thinking, what are lipids? Is it food? Why are they important? Well, all those questions and others will be resolved after reading this post.
First, lipids are made up of carbon, hydrogen, and oxygen, and phosphorus, nitrogen, or sulfur rarely appear. In general, they are not soluble in water but they are soluble in nonpolar organic solvents, such as ether, benzene or chloroform. Lidos are important since they provide energy to the body. In addition to what is evident, they are essential for the correct functioning of the body since there are vitamins such as A, D, E and K that are fat soluble, which means that they can only be digested, absorbed and transported together with lipids.
In the second scheme you can see the classification of lipids. However, in the former, the different types of complex lipids and the structures of sphingolipids and phospholipids can be better appreciated. The latter are very important, since they are found in the plasma membrane forming a bilayer with the hydrophilic heads facing the outside and the hydrophobic tails towards the inside. This phenomenon occurs thanks to the fact that they are amphipathic molecules, that is, they have a hydrophilic polar part that corresponds to the phosphate group and the polar substituents that bind to it, and another hydrophobic nonpolar part that are the fatty acids that esterify glycerin.
After the diagrams you can see the resolution of some activities proposed in class.
Source: wikimedia commons
Source: own images.
Activities
1. Regarding phospholipids:
a) Explain its chemical composition, referring to the type of bonds that bind its components.
Phospholipids are differentiated into phosphoglycerides, composed of glycerin, two fatty acids, and a phosphate group attached via an ester bond to an amino alcohol. On the other hand, we find the phosphoesphingolipids composed of sphingosine, fatty acid esters and a phosphate group linked by an ester-type bond to an amino alcohol.
b) In what cell structure are the phospholipids mostly located?
Phospholipids are mainly found in the plasma membrane forming a bilayer.
c) Explain what it means that phospholipids are amphipathic compounds and their implication in the organization of said structure.
Phospholipids are amphipathic, which means that they have a hydrophilic zone (soluble in water) and a hydrophobic zone (insoluble in water). This favors the formation of micelles, which can be monolayer, bilayer or liposome.
Source: wikimedia commons
2. Lipids are organic molecules present in all living beings with a great heterogeneity of functions.
a) State the chemical composition of a triacylglyceride of plant origin.
Triacylglycerides of vegetable origin, such as oils, are made up of three unsaturated fatty acids and glycerin.
b) Obtaining soap is based on a reaction in which some lipids take part; explain this reaction and indicate what it is called.
Saponification consists of the reaction of a fatty acid with a strong base to obtain a fatty acid salt (soap) and water.
c) Justify whether the olive oil used in the kitchen could be used to obtain soap.
Olive oil is an acylglyceride made up of unsaturated fatty acids and glycerin that reacts with a strong base to give soap and water.
3. Given the following structure, indicate:
a) What type of molecule is shown?
It is a triacylglyceride (hololipid).
b) State the main physical and chemical properties of this group of molecules.
Triacylglycerides are saponifiable, insoluble and nonpolar, which is why they are called neutral fats. They are made up of glycerin and one to three fatty acids. They have an energy reserve and thermal insulation function.
c) Where would you find these types of molecules in living animal and plant organisms?
These types of molecules are found in plants and constitute the main energy reserve of the animal organism. Excess lipids are stored in animals in adipose tissue and in plants in vacuoles.
I hope you find all this information useful and, see you in the next post! :-)
Information obtained from the syllabus and class notes.
