Four Macro Molecules in the Business of our Body
The biological cell is the basic unit on which our body structure gets constructed brick by brick, and then houses the organs that governs our trivial to vital functions. Cells are very small entity but do the big tasks. These tiny cells are made of macro-molecules which means linking together of smaller molecules. The four major macro-molecules are Proteins, Carbohydrates, Lipids and Nuclei Acids. There are different names to these macro molecules, for instance the Lipids are commonly known as Fats and the Carbohydrates are also known as Carbs in short. These four macro-molecules further comprises of smaller molecular components that defines the structuring and functioning of the single cell to the overall body.
In very short sentences…
Nucleic Acids stores information and messaging
Carbohydrates stores and supply instant energy
Lipids insulates and supply reserved energy
Proteins support structurally and functionally
In a long paragraph…
What does Proteins do?
Proteins are a class of biological molecules consisting of chains of amino acids, these are the building blocks. They own high nutritional value and controls the chemical processes essential for life. As a macro nutrient this are in the business of building the muscle mass. They do the majority of work in cell especially the structuring and functioning of body tissues and organs. Proteins are organ and species specific and different from one species to another, from one organ to another. Incidentally they comprises of 42% of the dry weight of our body. There are 20 different types of amino acids and 9 of them are essential that means they are needed in our food to stay healthy, and rest are non-essential but are synthesized in the body. These nine essential amino acids cannot be produced in the body and hence it comes from outside the body by the food we eat.
What does Carbohydrates do?
These are called carbohydrates because at the chemical level they comprise of carbon, oxygen and hydrogen atoms. And they get classified based on the degree of polymerization. Carbs are sugars or starches. Our digestive system converts the carbs into glucose. They contain the glucose that body needs for energy, and are soluble in water, carbs provider of instant energy. Body uses glucose as the primary source of energy for fulfilling its daily activities, and it can also store the carbohydrates as glycogen. And they usually cater to between 50-75% of the energy that is needed for the functioning of the body. Carbohydrates have 4 calories per gram.
What does Lipids do?
Lipids are commonly known as fats. The body uses lipids as the fuel source and fat forms the major storage of energy. They comprise of fatty acids, steroids, phospholipids and as these are made of three molecules hence called as triglyceride. Technically, fats are further classified as saturated, unsaturated and trans fat but essentially they are either good fats or bad fats. The food we eat comprises of different types and percentage of fats. Good to eat the unsaturated fats. Eating of saturated or trans fats increases the levels cholesterol which is bad for our body. Fats in balanced proportion basically help body absorb nutrients and produce important hormones.
What does Nuclei Acids do?
These are made of series of long molecules comprising of smaller molecules called as nucleotides. They carry the vital genetic information that passes from the parent to the offspring. There are two types of nuclei acids namely DNA and RNA, former is double stranded keeps the genetic information and the later is single strand coordinates the cell processes through protein synthesis. Essentially they play the role of maintaining and coordinating the various individual cell processes like cell division, cell repair and cell reproduction.
Nucleic Acids are DNA and RNA
Carbohydrates are sugar and starch
Lipids are fats and steroids
Proteins are Amino Acids
Proteins are derived from the Greek word “protas” connotes of primary importance it plays in the sustenance of life. It was discovered in 1838 by Jons Jacob Berzelius, a Swedish chemist. The most extensively studied molecule in subject of biochemistry.
The word saccharides come from Greek word “sakkharon” meaning sugar. Carbohydrates are mainly starch and sugar, and are made of monosaccharide. In the 19th century French physiologist Claude Bernard discovered glycogen.
In 1929-30, the husband-wife duo of George and Mildred Burr discovered fatty acids, critical component of fat. The body uses fat as source of fuel and the fat acts as major storage of energy.
In 1868, Swiss physician Friedrich Miescher discovered Nuclei Acid. It was named with their initial discovery within the nucleus. The term is the overall name of DNA and RNA. The main role is to store information to produce proteins.
Living organisms are made of molecules and molecules are composed of cells. It is all about the cell structure. The structure of the cell is constructed by the power of proteins. Human body is like a railway train with many compartments and the driver at the front in control of the engine.
Proteins are the wagons of the train and DNA the brain of the driver. RNA is the mirror image of DNA, it converts those written instructions into real actions that enables the functioning of our body parts and that’s what make life as a whole system. Proteins are typical mechanism that make or break other molecules. Unlike the carbohydrates the fats have a fear of water and they are therefore called as non-polar molecules and we also have the polar molecules. Lipids act as border for cells to exist as an independent entity and also co-exist as billions of cells in the body structure. Lipid comprises of fats, steroids and phospholipids, though lipid is commonly referred to as fat. They act as membrane within the cellular structure of the body. Carbohydrates are made of building blocks known as monosaccharide. Sucrose, glucose and fructose are carbohydrates. All these produces same amount of energy per gram but are processed and employed differently. Glucose is used as the main source of energy and fructose is used if additional energy is needed. Sugar is formed of two monosaccharide’s comprising of glucose and fructose. Plants during the process of photosynthesis use carbon dioxide, water and sunlight as energy and produces glucose. Glucose is also called blood sugars as it circulates in the blood streams. Fructose is the simplest form of carbohydrates; it needs to be converted into glucose by liver before it gets used by the body. We keep hearing the role of insulin in diabetics’ cases; basically it facilitates the entry of glucose into the cell. Unlike glucose, fructose doesn’t stimulate production of leptin, a hormone controls the demand and supply of energy. Glucose is used as the primary source of energy and when the body is in an inactive state, the glucose gets converted into fat but certain portion of glucose also gets converted into glycogen for storage in liver and muscles.
Just like HDL is good cholesterol and LDL is bad cholesterol similarly glucose is good carbohydrates and fructose is bad carbohydrates. Cholesterol is a major component of cell membranes and does important functions to produces hormones and vitamins to digest our food. It is basically an oil based substance and carried around the body by lipoproteins and there are two types namely HDL and LDL.
A balanced dietary plan should comprise of right combination of carbs, fats and proteins, for the overall calorie requirements of the functioning of body and mind. The exact ratio depends on the body structure and the workings one does on one’s body.
For instance there is a ratio generally recommended for a normal body structure doing standard set of daily works as 2:1:1 i.e. 50% carbs, 25% fats and 25% proteins. All work together to keep the body healthy and functioning well. These three macro-nutrients contribute to 90% of the dry weight and cater to the 100% of energy requirement of the body.
Take any cell out of our body and we will have the protein in it and inside the proteins are amino acids the small organic molecules that bind together to form the macromolecule we know as protein. Human usage protein as the last option for meeting the shortfall in energy requirement and excess of protein consume results in fat formation.
The elements of carbon, hydrogen and oxygen combines to form the sugar molecule, and these together form the macromolecule we know as carbohydrates. They act the first source of energy and excess consumption of it converts and get stored as glycogen.
Fat is not a negative word, it has a positive work to do, only that it changes it’s color the moment there is an excess accumulation. It acts as an energy storage medium and when the primary energy source is depleted this source comes into play. They make up the cell membrane and prevent unwanted things to enter.
DNA contains the genetic blueprint. RNA is the reader of that code and converts that into a set of actions to produce proteins. Human body doesn’t use Nuclei Acids for meeting the energy requirement.
The food is not merely a source of energy for our body but the composition of ingredients in food ignites food for thought when we focus our camera with these four different lens. Each of this micro lens throws something new onto the canvas when we look with a macro outlook. The idea is to reflect on the items we eat and not just eat for the sake of calories which is the case and we have taken eating part of routine and the body for granted.
We needn’t be a doctor or a scientist or a chemist to know the complexity of these macro molecules but as common person we can very well understand and appreciate the technical terms when lucidly crafted in simple words.
Nihar R Pradhan