Biomolecules- The Lipids

[This post takes 2-4 min. to read]

First things first…


[‘Tis the season to be jolly, falalalalalalalala]

Okay, moving on…

I bet you guys are like, DONE with biomolecules, so I have some awesomesauce! Today is the last post on Biomolecules. The next post will be about Chemistry! So, all you have to do is survive through today’s post…


Anyways, without further ado…

What are fats?

Fats are an extremely important biomolecule, characterised by their insolubility in water. They play many crucial roles in the body, from insulation to storing energy to chemical signals. There are three common kinds of fats.

Types of fats–>

There are three types of fats- steroids, diglycerides and triglycerides. Triglycerides are more commonly refered to as fats and oils, while diglycerides are also known as phospholipids. Steroids are just… well, steroids. Yeah. Sorry, steroids. We’ll find you a better nickname sometime else.


Triglycerides all have long chains of 3 fatty acids attached to a glycerol group. The glycerol group has 3 carbon atoms, and one fatty acid is attached to one carbon atom. The fatty acid chains are entirely composed of hydrogren and carbon atoms- and they are hydrophobic, meaning they repel water. The glycerol group, however, is hydrophilic, meaning it attracts water. Overall, however, triglycerides and actually, all fats are insoluble in water.

There are 3 kinds of fatty acids that can compose triglycerides- unsaturated fatty acids, saturated fatty acids and polyunsaturated fatty acids.[You know what? One of these days, I’m going to compile all the tongue twister-y words that science often uses and post it. There should be about five thousand. Nah. Kidding.]


Diglycerides is basically a fancy way of saying phospholipids [remember phospholipids?!]. Phospholipids have a head made of glycerol and phosphate[hence the phospho part of the word phospholipid], and two tails made of fatty acids. The tail with a bend in it is an unsaturated fatty acid, while the tail which is straight is a saturated fatty acid.

The arrangement of atoms in the phospholipid gives it a hydrophilic head and hydrophobic tails. Overall, however, diglycerides, like all lipids, are insoluble in water. Phospholipids make up a huge part of every cell’s cell membrane, arranging themselves in a way that the tails face inward, making the interior of a cell membrane hydrophobic with the intracellular and extracellular parts being hydrophilic.


Steroids are the weird kid of the class. They are fats- but they have no fatty acids. Steroids are actually made up of 4 rings of carbohydrates, with hydrogen sticking out here and there. The above steroid- gonane, is a nucleus steroid. Chemicals like bile acids, cortisone and cholestrol are all steroids. Cholestrol is the most abundant steroid in the body. Steroids have a vast array of functions- some function as signalling molecules, others are an extremely dense source of energy, while a few make up components of the cell membrane.

How eating fats aren’t actually going to make you fat–>

I know! Crazy, right?

Okay. Let me explain.

Hormones regulate everything inside the body. If you want to burn your own body fat, it turns out that the hormone insulin has to be at a low level. This is because insulin tells your body to scrape out all the fatty acids from the blood and store them in the cells. When you eat carbs, your body floods the blood with insulin- which means more fat in the cells, and less time in fat-burning mode.

The hormone leptin makes you satisfied- but insulin’s presence interferes with leptin’s, and you end up still feeling hungry, so you eat more. This is the perfect recipe to weight gain. I hope that you now know that the real villains aren’t fats, but carbs.

We are finished for today- the next post will be chemistry[AT LAST!]

Thank you, and Merry Christmas!

OH WAIT I almost forgot the Space Bonus-

Okay now bye.

Published by girrrrrl_of_two_worlds

hi! just a nerdy girl here. lover of science, english and learning on the whole. spreading knowledge is one of my favorite things to do! nothing in life is to be feared, it is only to be understood. now is the time to understand more, so that we may fear less. ~marie curie

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