Carbohydrates

Carbohydrates

There are some tables in your book in chapter 2. They do a great job at summarizing the functions of the organic moleculesGroups of atoms bonded together.. But, the reality is that these 4 categories can have overlapping functions.  So, we have to narrow the focus to the most important function of each.  For carbohydrates, that means defining them as the primary energyThe capacity to do work or cause change. source for the body.  This is mainly because carbohydrates all have pretty simple structures compared to the other three categories of organic compounds.  Yes, I know there are things called complex carbs. However, that is only 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. 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.. It also manages 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.  The pancreas tells the liver what to do. However, 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, carbohydrates you consume are broken down into monosaccharides. These are 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.  You might look at maltose here. The two green glucoseA simple sugar that is the main source of energy for cells. molecules are bonded together. You might 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

Consider the extra bond in disaccharides. Now think of how much extra energy a molecule has 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 because they are bigger with more bonds. You could also say that they are more complex for your digestive system to break down.  Therefore, it takes longer. It’s similar to a time-release capsule. It slowly releases glucose into the blood plasma. This happens 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.