Carbon is a very unique element in that it has four valence electrons in its outer orbitals and can form four single covalent bonds with up to four other atoms at the same time see Fundamentals of Physics and Chemistry Important to Microbiology. These atoms are usually oxygen, hydrogen, nitrogen, sulfur, phosphorous, and carbon itself; the simplest organic compound is methane, in which carbon binds only to hydrogen Figure 2.
Figure 2. A carbon atom can bond with up to four other atoms. The simplest organic molecule is methane CH 4 , depicted here. The carbon skeleton of organic molecules can be straight, branched, or ring shaped cyclic. Organic molecules are built on chains of carbon atoms of varying lengths; most are typically very long, which allows for a huge number and variety of compounds. No other element has the ability to form so many different molecules of so many different sizes and shapes. Molecules with the same atomic makeup but different structural arrangement of atoms are called isomers.
The concept of isomerism is very important in chemistry because the structure of a molecule is always directly related to its function. Slight changes in the structural arrangements of atoms in a molecule may lead to very different properties. Chemists represent molecules by their structural formula , which is a graphic representation of the molecular structure, showing how the atoms are arranged. Compounds that have identical molecular formulas but differ in the bonding sequence of the atoms are called structural isomers.
The monosaccharides , glucose , galactose , and fructose all have the same molecular formula, C 6 H 12 O 6 , but we can see from Figure 3 that the atoms are bonded together differently. Glucose, galactose, and fructose have the same chemical formula C 6 H 12 O 6 , but these structural isomers differ in their physical and chemical properties.
Isomers that differ in the spatial arrangements of atoms are called stereoisomers ; one unique type is enantiomers. The properties of enantiomers were originally discovered by Louis Pasteur in while using a microscope to analyze crystallized fermentation products of wine.
Enantiomers are molecules that have the characteristic of chirality , in which their structures are nonsuperimposable mirror images of each other. Chirality is an important characteristic in many biologically important molecules, as illustrated by the examples of structural differences in the enantiomeric forms of the monosaccharide glucose or the amino acid alanine Figure 4.
Many organisms are only able to use one enantiomeric form of certain types of molecules as nutrients and as building blocks to make structures within a cell. Some enantiomeric forms of amino acids have distinctly different tastes and smells when consumed as food. For example, L-aspartame, commonly called aspartame, tastes sweet, whereas D-aspartame is tasteless.
Drug enantiomers can have very different pharmacologic affects. For example, the compound methorphan exists as two enantiomers, one of which acts as an antitussive dextro methorphan, a cough suppressant , whereas the other acts as an analgesic levo methorphan, a drug similar in effect to codeine.
Figure 4. Enantiomers are stereoisomers that exhibit chirality. Their chemical structures are nonsuperimposable mirror images of each other. Enantiomers are also called optical isomers because they can rotate the plane of polarized light. Some of the crystals Pasteur observed from wine fermentation rotated light clockwise whereas others rotated the light counterclockwise. The d and l labels are derived from the Latin words dexter on the right and laevus on the left , respectively.
These two different optical isomers often have very different biological properties and activities. Certain species of molds, yeast, and bacteria, such as Rhizopus , Yarrowia , and Lactobacillus spp. Another important reason to be aware of optical isomers is the therapeutic use of these types of chemicals for drug treatment, because some microorganisms can only be affected by one specific optical isomer.
In addition to containing carbon atoms, biomolecules also contain functional groups —groups of atoms within molecules that are categorized by their specific chemical composition and the chemical reactions they perform, regardless of the molecule in which the group is found. Some of the most common functional groups are listed in Table 1. R might symbolize just a single hydrogen atom or it may represent a group of many atoms.
Notice that some functional groups are relatively simple, consisting of just one or two atoms, while some comprise two of these simpler functional groups. It is present in several classes of organic compounds as part of larger functional groups such as ketones, aldehydes, carboxylic acids, and amides.
In ketones, the carbonyl is present as an internal group, whereas in aldehydes it is a terminal group. Carbon chains form the skeletons of most organic molecules. Because these are finite raw materials, a lot of industry focus is on learning how to convert renewable resources e. The largest-volume petroleum products are fuel oil and gasoline. Petroleum is also the raw material for many chemical products e.
The pharmaceutical industry develops, produces, and markets drugs used as medications for humans or animals. Some pharmaceutical companies deal in brand-name i. Pharmaceuticals brand name and generic and medical devices are subject to many country-specific laws and regulations regarding patenting, testing, safety assurance, efficacy, monitoring, and marketing. Federal offices e. Collaborate with other chemists, keep up-to-date with new developments in the field and stay connected to your community.
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Funding Funding to support the advancement of the chemical sciences through research projects. What is organic chemistry? What do organic chemists do? Where is organic chemistry used? Which industries hire organic chemists? Common employment areas in biotechnology include: Health care Crop production and agriculture Nonfood uses of crops Consumer products e.
What is an organic compound? What is a macromolecule? What are the four classes of biomolecules found in living things? Number of carbons that form the backbone of an organic compound, and shape of it long chain, branched chain, ring are not the only features that determine organic compounds properties.
Groups of atoms of other elements associated to the carbon backbone give unique properties to the millions of different types of organic molecules. A specific group of atoms linked by strong covalent bonds is called a functional group. There are many important functional groups in human physiology. Some of them are hydroxyl, carboxyl, amino, methyl and phosphate groups. Study Questio n Write your answer in a sentence form do not answer using loose words.
Learning objectiveS Define the terms organic compound and macromolecule, and list the four groups of organic compounds found in living matter Define functional groups and give examples. Concepts, terms, and facts check Study Question Write your answer in a sentence form do not answer using loose words 1.
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