Depending on the number of carbon atoms in the sugar, they may be known as trioses (three carbon atoms), pentoses (five carbon atoms), and hexoses (six carbon atoms). Most monosaccharide names end with the suffix -ose. In monosaccharides, the number of carbon atoms usually ranges from three to six. Monosaccharides (mono- = “one” sacchar- = “sweet”) are simple sugars, the most common of which is glucose. Carbohydrates are classified into three subtypes: monosaccharides, disaccharides, and polysaccharides. In other words, the ratio of carbon to hydrogen to oxygen is 1:2:1 in carbohydrate molecules. Carbohydrates also have other important functions in humans, animals, and plants.Ĭarbohydrates can be represented by the formula (CH 2O) n, where n is the number of carbon atoms in the molecule. Carbohydrates provide energy to the body, particularly through glucose, a simple sugar. Carbohydrates are, in fact, an essential part of our diet grains, fruits, and vegetables are all natural sources of carbohydrates. Athletes, in contrast, often “carb-load” before important competitions to ensure that they have sufficient energy to compete at a high level. To lose weight, some individuals adhere to “low-carb” diets. CarbohydratesĬarbohydrates are macromolecules with which most consumers are somewhat familiar. (c) Glucose, a sugar, has a ring of carbon atoms and one oxygen atom. (b) Glycine, a component of proteins, contains carbon, nitrogen, oxygen, and hydrogen atoms. (a) This molecule of stearic acid has a long chain of carbon atoms.
Figure 2.13 These examples show three molecules (found in living organisms) that contain carbon atoms bonded in various ways to other carbon atoms and the atoms of other elements. This diversity of molecular forms accounts for the diversity of functions of the biological macromolecules and is based to a large degree on the ability of carbon to form multiple bonds with itself and other atoms. The molecules may also form rings, which themselves can link with other rings ( Figure 2.13 c). The carbon atoms may bond with atoms of other elements, such as nitrogen, oxygen, and phosphorus ( Figure 2.13 b). In this way, long and branching chains of carbon compounds can be made ( Figure 2.13 a). Any of the hydrogen atoms can be replaced with another carbon atom covalently bonded to the first carbon atom. However, structures that are more complex are made using carbon. The simplest carbon molecule is methane (CH4), depicted here. Figure 2.12 Carbon can form four covalent bonds to create an organic molecule. The simplest organic carbon molecule is methane (CH 4), in which four hydrogen atoms bind to a carbon atom. Therefore, it can form four covalent bonds with other atoms or molecules. Carbon BondingĬarbon contains four electrons in its outer shell. It is the bonding properties of carbon atoms that are responsible for its important role. Other elements play important roles in biological molecules, but carbon certainly qualifies as the “foundation” element for molecules in living things. It is often said that life is “carbon-based.” This means that carbon atoms, bonded to other carbon atoms or other elements, form the fundamental components of many, if not most, of the molecules found uniquely in living things.
In addition, they may contain hydrogen, oxygen, nitrogen, phosphorus, sulfur, and additional minor elements. Biological macromolecules are organic, meaning that they contain carbon. Combined, these molecules make up the majority of a cell’s mass. There are four major classes of biological macromolecules (carbohydrates, lipids, proteins, and nucleic acids), and each is an important component of the cell and performs a wide array of functions.
The large molecules necessary for life that are built from smaller organic molecules are called biological macromolecules.
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