What makes carbon unique among the elements

Long chains of carbon atoms with double and triple bonds are quite common in biology. Carbon's tendency toward covalent bonding with itself generates three unique characteristics that create a vast array of compounds, including those necessary to construct and support life:. Carbon to carbon C-C bonds form the backbone of all biomolecules and can include thousands of C-C bonds.

In the simplest terms, the reactive part of any compound is called the functional group. Normally a functional group is a collection of atoms that operates as one reactive unit and is also the part of the molecule involved in a chemical reaction.

Whereas carbon-to-carbon bonds are nonreactive, the instability of the functional groups drives chemical reactions that involve stable carbon-based compounds. For simplicity and reference, three functional groups are presented:. A hydration reaction is the reverse of a dehydration reaction in that water serves as a reactant to split apart large poly-molecules.

Some of the important functional groups in biological molecules include: hydroxyl, methyl, carbonyl, carboxyl, amino, phosphate, and sulfhydryl groups. These groups play an important role in the formation of molecules like DNA, proteins, carbohydrates, and lipids. Functional groups are usually classified as hydrophobic or hydrophilic depending on their charge or polarity.

An example of a hydrophobic group is the non-polar methane molecule. Among the hydrophilic functional groups is the carboxyl group found in amino acids, some amino acid side chains, and the fatty acid heads that form triglycerides and phospholipids. Other functional groups, such as the carbonyl group, have a partially negatively charged oxygen atom that may form hydrogen bonds with water molecules, again making the molecule more hydrophilic.

Hydrogen bonds between functional groups within the same molecule or between different molecules are important to the function of many macromolecules and help them to fold properly and maintain the appropriate shape needed to function correctly. Hydrogen bonds are also involved in various recognition processes, such as DNA complementary base pairing and the binding of an enzyme to its substrate. Privacy Policy.

Skip to main content. The Chemical Foundation of Life. Search for:. The Chemical Basis for Life Carbon is the most important element to living things because it can form many different kinds of bonds and form essential compounds.

Learning Objectives Explain the properties of carbon that allow it to serve as a building block for biomolecules. Key Takeaways Key Points All living things contain carbon in some form. Carbon is the primary component of macromolecules, including proteins, lipids, nucleic acids, and carbohydrates. The carbon cycle shows how carbon moves through the living and non-living parts of the environment.

Key Terms octet rule : A rule stating that atoms lose, gain, or share electrons in order to have a full valence shell of 8 electrons has some exceptions.

Hydrocarbons Hydrocarbons are important molecules that can form chains and rings due to the bonding patterns of carbon atoms. Learning Objectives Discuss the role of hydrocarbons in biomacromolecules. Key Takeaways Key Points Hydrocarbons are molecules that contain only carbon and hydrogen. The bonding of hydrocarbons allows them to form rings or chains. Key Terms covalent bond : A type of chemical bond where two atoms are connected to each other by the sharing of two or more electrons.

Organic Isomers Isomers are molecules with the same chemical formula but have different structures, which creates different properties in the molecules. Learning Objectives Give examples of isomers.

Key Takeaways Key Points Isomers are molecules with the same chemical formula but have different structures. Isomers differ in how their bonds are positioned to surrounding atoms. Triglycerides, which show both cis and trans configurations, can occur as either saturated or unsaturated, depending upon how many hydrogen atoms they have attached to them.

Organic Enantiomers Enantiomers share the same chemical structure and bonds but differ in the placement of atoms such that they are mirror images of each other. Learning Objectives Give examples of enantiomers. Key Takeaways Key Points Enantiomers are stereoisomers, a type of isomer where the order of the atoms in the two molecules is the same but their arrangement in space is different. Many molecules in the bodies of living beings are enantiomers; there is sometimes a large difference in the effects of two enantiomers on organisms.

Key Terms enantiomer : One of a pair of stereoisomers that is the mirror image of the other, but may not be superimposed on this other stereoisomer. Organic Molecules and Functional Groups Functional groups are groups of molecules attached to organic molecules and give them specific identities or functions. The carbon atom's four valence electrons can be shared by other atoms that have electrons to share, thus forming covalent shared-electron bonds.

They can even be shared by other carbon atoms, which in turn can share electrons with other carbon atoms and so on, forming long strings of carbon atoms, bonded to each other like links in a chain. Silicon Si , another element in group 14 of the periodic table, also has four valence electrons and can make large molecules called silicones, but its atoms are too large to fit together into as great a variety of molecules as carbon atoms can.

Carbon's ability to form long carbon-to-carbon chains is the first of five reasons that there can be so many different carbon compounds; a molecule that differs by even one atom is, of course, a molecule of a different compound. The second reason for carbon's astounding compound-forming ability is that carbon atoms can bind to each other not only in straight chains, but in complex branchings, like the branches of a tree. However, the millions of organic compounds can be grouped into just four major types: carbohydrates , lipids , proteins , and nucleic acids.

You can compare the four types in Table below. Each type is also described below. Carbohydrates , proteins, and nucleic acids are large molecules macromolecules built from smaller molecules monomers through dehydration reactions.

In a dehydration reaction, water is removed as two monomers are joined together. Is it possible to extract energy from leftovers? Can organic waste become useful? It may look like waste, but to some people it's green power.

Find out how California dairy farms and white tablecloth restaurants are taking their leftover waste and transforming it into clean energy. The Significance of Carbon A compound found mainly in living things is known as an organic compound. Compounds A compound is a substance that consists of two or more elements. Carbon Why is carbon so basic to life? Type of Compound Examples Elements Functions Monomer Carbohydrates sugars, starches carbon, hydrogen, oxygen provides energy to cells, stores energy, forms body structures monosaccharide Lipids fats, oils carbon, hydrogen, oxygen stores energy, forms cell membranes, carries messages Proteins enzymes, antibodies carbon, hydrogen, oxygen, nitrogen, sulfur helps cells keep their shape, makes up muscles, speeds up chemical reactions, carries messages and materials amino acid Nucleic Acids DNA, RNA carbon, hydrogen, oxygen, nitrogen, phosphorus contains instructions for proteins , passes instructions from parents to offspring, helps make proteins nucleotide Carbohydrates , proteins, and nucleic acids are large molecules macromolecules built from smaller molecules monomers through dehydration reactions.

Energy From Carbon?