Let’s talk about food, let’s talk about F-O-O-D! Yes, food does get me excited. *stomach growls* What are the major food groups that we consume everyday? But first, let’s talk metabolism.
We talk about having slow or fast metabolism all the time. But what does metabolism actually mean? Metabolism is the sum of the processes in the buildup and destruction of the organelles of cells. In other words, the breaking down and build up of stuff in a cell. You could also define metabolism as the chemical changes in living cells by which energy is provided for vital processes and activities, while new material is assimilated. For example, let’s think about cows. Cows only eat grass but those cows end up as steak for our Valentine’s Day dinner. It’s the process of grass getting broken down to become meat that is called metabolism.
In any living organism, there is always two parts to metabolism. Catabolism and anabolism. Catabolism means to break down, and anabolism means to construct stuff. So remember that catabolism+anabolism=metabolism.
Now that we know what metabolism actually means, let’s finally move on to talk about food.
There are 3 primary food groups that you hopefully consume everyday. Carbohydrates, lipids, and protein. This is a photo of some chicken soup I made the other day and let’s go through the food groups in this soup. There are some carbohydrates in the form of vegetables and a bit of rice I put in the soup, protein in the form of some chicken, and a bit lipid floating on top in the form of some olive oil I used for sautéing my mirepoix. We consume these naturally occurring forms of our major food group everyday so it must be important, right? Well if you agree, let’s learn a bit more about them, shall we?
Carbohydrates. The scary freaky carbs that I thought was the short cut to weight gain during my teenage years. But let’s take a look at carbohydrate from a molecular level. It is always composed of 3 elements; carbon, hydrogen, and oxygen. The smallest/simplest unit of carbohydrates is in the form of a sugar called monosaccharide. You may have heard of glucose (also called dextrose), fructose, and galactose which are all different molecules of monosaccharides. When two monosaccharides are covalently bonded together, they form what is called a disaccharide. 2 glucose molecules bonded together are called maltose, a glucose and a galactose molecules bonded together is called lactose, and a glucose and fructose molecules bonded together is called sucrose.
There are some common properties that mono and disaccharides share together. You probably noticed that all the words of these molecules end with the suffix -ose, which means that it’s a sugar molecule, so therefore they obviously taste sweet. They are also soluble in water contrary to the insoluble polysaccharides that I will be explaining now. You may have guessed that polysaccharides probably have many monosaccharides bonded together, and you would have guessed correctly. Polysaccharides are many units of monosaccharides linked together by glycosidic bonds that help with storing energy. A common form of a polysaccharide is the bunch the glucose molecules called cellulose.
You may have guessed that polysaccharides probably have many monosaccharides bonded together, and you would have guessed correctly. Polysaccharides are many units of monosaccharides linked together by glycosidic bonds that help with storing energy. A common form of a polysaccharide is the bunch the glucose molecules called cellulose which is an indigestible polysaccharide because humans do not have not appropriate enzymes to break them down. But most of our polysaccharides are consumed in the form of starch which is digestible. Starch is found in plants and is used as food that helps with slow releasing energy compared to another form of a polysaccharide, glycogen. Glycogen is the stored form of glucose in the liver and muscles, which gives fast access to energy because it is easier to breakdown than starch. I will explain in a future post about how glucose is converted to energy when I write about ATP.
Let’s move on to proteins. The holy grail for gaining muscle that we always talk about when we are in a conversation with a vegan individual. “How do you get your protein then?” Seriously, I’m not a vegan but stop asking that to vegans, people. Anyways, protein molecules are made up of 4 elements; carbon, hydrogen, oxygen, and nitrogen. Its monomer is called amino acid, and there are 20 different types of amino acids. Out of the 20, 9 are essential amino acids that our body requires but cannot produce. And as we know, proteins are important for forming muscle, hormones, and enzymes in the body. I don’t have to go through sources of protein, right?
I mentioned that monomers of protein are amino acids. So when do amino acids become protein? Protein is formed when amino acids are bonded together. But before amino acids become protein, if between 2-50 amino acids are bonded together, they are called peptides. Polypeptides are when there are 50-100 amino acids bonded together and finally protein is formed when over 100 amino acids are bonded together. And the bonds between the amino acids are called peptide bonds.
And last but not least of our major food group, lipids. Lipids, also known as fats, are also comprised of carbon, hydrogen, and oxygen like carbohydrates, but in different structures which do not allow them to be water soluble. There are 2 types of lipids. Saturated and unsaturated lipids. The difference between saturated and unsaturated fats depend on their molecular structure. It all depends on whether or not the carbons in the lipid molecules are bonded once or twice to the carbon next to it. As you can see in the diagram, the unsaturated lipid molecule has two carbons that are bonded together twice. These differences in the molecular structure give the lipids different properties. Saturated fats are often solid at higher temperatures like butter, cocoa butter, or coconut oil. Unsaturated fats, however, have more distance between the molecules, therefore are often liquid at room temperature. Such as olive oil, truffle oil, and sesame oil. Also, unsaturated fats can sometimes form into trans-unsaturates fats which are denser than normal unsaturated fats. These trans fats are dangerous for your health because of its unique chemical structure and I will explain this when I start my chemistry revision in 1 week.
There are 3 types of lipids; triglycerides, sterols (cholesterol), and phospholipids. Cholesterol and phospholipids are what cell membranes are made of. Triglycerides are lipids you obtain from food that stores energy in your bodies main fat storage site, adipose tissues. Triglycerides are composed of glycerol and 3 fatty acids bonded together as you can see in the diagram here. Triglycerides have many different types and the types are mainly divided by whether they are saturated or unsaturated. However, sometimes triglycerides are in the form of polyunsaturated fats which means that they have more than one double-bonded pair of carbon in its molecular structure.
So that is it for our major food group guys. Hope this was an interesting post as food is such a big part of our lives. Next time I will be writing about how these foods we consume end up being used for energy. Till then!