OLE Lesson 7.6A: Organic Compounds
What is a compound?
Compounds form when two or more elements combine chemically. For example, water is
a compound made up of the elements hydrogen and oxygen. The smallest unit of a
compound is a molecule. A molecule of water consists of one oxygen atom and two
hydrogen atoms. Most elements in living things occur in the form of compounds.
What are organic compounds?
An organic compound contains atoms of carbon bonded to one another and to other kinds of atoms. However,
not all compounds that contain carbon are necessarily organic. Some compounds that contain carbon, such as
carbon dioxide, are not organic compounds. Carbon atoms bond to each other very easily and in several ways,
so carbon is able to form many compounds—over 10 million that are known so far!
In these diagrams, lines represent chemical bonds that can form between atoms. You can see that carbon atoms
can bond in many ways.
In addition to carbon atoms, organic compounds may
contain atoms of hydrogen, oxygen, nitrogen, sulfur,
phosphorus, and other elements. Originally, scientists
thought only living things produced organic
compounds. In the early nineteenth century, however,
scientists began synthesizing organic compounds.
Examples include synthetic rubber, nylon, and aspirin.
1.Identify What element do all organic compounds contain? _____________
Carbon and Hydrogen Hydrocarbons are organic compounds that contain only atoms of carbon and
hydrogen. These compounds consist
of one or more carbon atoms to which are bonded hydrogen
atoms. Different numbers of each type of atom produce different
compounds.
The simplest hydrocarbon is methane. Methane is made up of a
single carbon atom linked to four hydrogen atoms. The formula
for methane is CH4. The next two simplest hydrocarbons are
ethane (C2H6) and propane (C3H8). A structural formula shows the arrangement of atoms in a molecule of a
compound. The diagram below shows the structural formulas for methane, ethane, and propane.
2.Identify Hydrocarbons are organic compounds. Identify the elements that hydrocarbons contain.
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Carbon and Oxygen Some organic compounds, such as
alcohols and organic acids, contain oxygen atoms.
Examples of alcohols include methanol, ethanol, and
isopropyl alcohol. Molecules of alcohol contain oxygen
and hydrogen atoms bonded to carbon.
Examples of organic acids include formic acid and acetic
acid. Formic acid produced by ants is what makes their bites painful. Acetic acid is the main component of
vinegar. Other examples of oxygen-containing organic compounds include carbohydrates and lipids. Sugars and
starches in food are carbohydrates. Fats and oils are lipids.
3.Identify Alcohols are organic compounds. What three elements form types of alcohol?
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Other Organic Compounds Amino acids, which contain nitrogen, are
among the most important organic compounds in living things. These
compounds are the building blocks of proteins; and proteins are, in turn, the
building blocks of an organism’s tissues and organs. Your heart, blood, brain
tissue, skin, nerves, and muscles all contain proteins. Proteins are larger
molecules made up of combinations of 20 different kinds of amino acids. In
Structure of DNA
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addition to carbon, hydrogen, oxygen, and nitrogen, two of these amino acids also contain an atom of sulfur.
DNA, deoxyribonucleic acid, is perhaps the most complex organic compound. It is the substance in cells that
determines the genetic makeup of all living things. The structure of DNA looks like a twisted ladder, or spiral
staircase, with steps made of units called nitrogen bases. As their name indicates, these “steps” include atoms of
nitrogen. The “banister” of the DNA staircase is made of sugar units connected to phosphate units. The
phosphate units contain atoms of the element phosphorus.
4.Identify List three additional elements that bond with carbon, hydrogen, and oxygen in the formation of
amino acid and DNA.
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Lesson Check
1.Identify Identify the element that all organic compounds have in common.
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2.Identify Identify elements that bond with carbon in the following organic compounds:
a. methane
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b. methanol
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c. amino acid
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3.Analyze Characterize the relationship between organic compounds and living things.
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Identify An organic acid is an organic compound. In addition to carbon and hydrogen, what other element does
it contain?
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2.Identify Which organic compound contains phosphorus?
A alcohol
B DNA
C hydrocarbon
D amino acid
3.Identify Of these organic compounds, identify the type that contains nitrogen.
A methane
B ethanol
C amino acid
D formic acid
4.Compare and Contrast Amino acid and alcohol are organic compounds.
a. Identify the elements found in amino acid.
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b. Identify the elements found in alcohol.
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c. Now compare and contrast the elements found in amino acid with those found in alcohol.
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5.Identify You have been asked to identify an unknown organic compound. You discover that it is a relatively
small molecule that contains atoms of sulfur. You narrow down your choices to a protein, an amino acid, and a
simple hydrocarbon. Which do you choose? Explain your answer.
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