Functional Groups
Biology
Recognize these Functional Groups
Like flags dangling on the outer surface of biological molecules, these small chemical species influence local chemical behavior. Watch our video for more details about the kinds of chemical reactions involving these different functional groups.
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\(-OH\) Hydroxyl Group: highly reactive, hydrophilic
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\(=CO\) Carbonyl Group: polar, increases solubility in water.
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\(-COOH\) Carboxyl Group: acidic (donates \(H^+\)), found in aldehydes & ketones
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\(-NH_2\) Amine Group: basic (accepts \(H^+\))
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\(-(PO_4) ^{3-}\) Phosphate Group: acidic (increases \(H^+ \)concentration)
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\(-SH\) Sulfhydryl Group: forms disulfide bridges with other \(-SH\) groups
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\(-CH_3\) Methyl Group: nonpolar (hydrophobic)
What's on the Surface?
Superficial details can matter
In biological molecules, the carbon skeleton determines their general 3D shape. But what’s on the surface of the molecules determines their chemical behavior. Small chemical species, hanging off the exterior of these molecules, bump into each other and react. These are known as FUNCTIONAL GROUPS. To understand what kinds of chemical reactions biological molecules can do, you have to understand the chemical behavior of the functional groups on the surface of the molecule.
Recommended reading
The definitive text
Campbell's Biology is the standard text used in most first-year college biology courses. Reliably researched and well-written, with clear illustrations.
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