Biological Molecules: Carbohydrates

Carbohydrates

Carbohydrates are the primary energyThe capacity to do work or cause change. source for most cellsThe basic structural and functional units of life..  This is mainly because carbohydrates all have pretty simple structures compared to the other three categories of organic compounds.  Yes, I know that there are things called complex carbs, but that is a nutritional term meant to compare carbs to carbs.  All carbohydrates are hydrophilic and waterThe universal solvent essential for life. loving.  This means that they are very soluble in the water part of the blood, called plasmaThe liquid component of blood..  Carbohydrates are used by every single cell in your body, but the liverA large organ that produces bile, detoxifies blood, and stores nutrients. is really responsible for their anabolismThe metabolic process that builds complex molecules from simpler ones, requiring energy. and also for the management of the excess.  I know, the pancreasA gland that produces digestive enzymes and hormones like insulin and glucagon. comes to mind first, but it’s just a manager here, not a doer.  It tells the liver what to do, but it is the liver that actually adjusts the carbohydrateOrganic molecules composed of carbon, hydrogen, and oxygen, primarily used for energy. levels in the blood plasma.

Monosaccharides

Did you notice that the chemical formula for a carbohydrate is reflected in their name?  Carbo, meaning carbon, and hydrate meaning water.  Every carbohydrate is just a water molecule with a carbon slapped onto it.  Monosaccharides are just monomers These hexagon and pentagon shapes are how we represent monosaccharides structures.  At each point of the shape, we assume that there is a carbon atomThe smallest units of matter that retain the properties of an element., bonded to the items indicated.  We refer to monosaccharide as “simple” sugars in our diets.  Glucose and fructose are really the most common monosaccharide is the human body, but galactose is a close third.  In the most simplistic terms – whatever type of carbohydrates you consume, they get broken down to these, which are easily used in cellular respirationThe process of gas exchange, including ventilation, external and internal respiration. to make ATPThe energy currency of cells used for muscle contraction..

Disaccharides

Disaccharides are just two monosaccharides bonded together.  So, you might look at maltose here, the two green glucoseA simple sugar that is the main source of energy for cells. moleculesGroups of atoms bonded together. bonded together and assume that it has twice as much energy as one glucose molecule.  Untrue.  It has just a little but more than twice because of the bond that bonds the two monosaccharides together.  That extra bond adds just a bit more than the two combined.  That extra bond also makes disaccharides Carbohydrates composed of two monosaccharide units. just a tad bit more difficult to break down during digestion.  Speaking of digestion, I’m glad we have lactoseA disaccharide sugar found in milk. here.  The lactase enzyme breaks down lactose in dairy products.  You either have it or you don’t.  If you don’t, you can’t break that extra bond.  Lactose then passes through your digestive system undigested.  I do not know personally, but I hear it is not a pleasant experience.

Polysaccharides

Considering that extra bond in disaccharides, now think of how much extra energy a molecule with tons of glucose monomers strung together.  Carbohydrate polymersLarge molecules made of repeating monomer units. like this are called polysaccharides and are usually referred to as “complex carbs.”  You can consider them complex just because they are bigger with more bonds, but you could also say that they are more complex for your digestive system to break down.  Therefore it takes longer, like a time-release capsule slowing releasing glucose into the blood plasma as one-by-one the monomers are torn off by hydrolysis.  Glycogen is the polysaccharide you make in your liver when there is excess glucose floating around in your blood plasma.  When you get hangry, that glycogenA storage form of glucose found in animals. is catabolized and the glucose is released into the blood. When you eat animals, you are consuming their glycogen.  When you eat plants, you are consuming their polysaccharide called starch.

Benefits of Carbohydrates

Your body breaks down carbohydrates into glucose, which is the simplest form of sugar and the main energy source for your cells. Whether you’re running, studying, or just going about your daily tasks, your body needs glucose for energy. Your body can also store glucose in the form of glycogen in your muscles and liver for later use. If you run low on energy during exercise, your body can break down glycogen to give you a quick boost.

Fiber, a type of carbohydrate that your body can’t digest, is essential for keeping your digestive system healthy. Fiber helps prevent constipation, keeps the intestines clean, and promotes the growthAn increase in size and number of cells. of healthy bacteria in your gut. It also plays a role in lowering the risk of certain diseases like heart disease and diabetes.