BackSix Functional Groups Commonly Attached to Carbon Atoms
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Six Functional Groups Commonly Attached to Carbon Atoms
Functional groups are specific groups of atoms within molecules that are responsible for the characteristic chemical reactions of those molecules. In organic and biological chemistry, understanding these groups is essential for predicting molecular behavior and reactivity.
Amino Group
The amino group is a fundamental functional group in organic molecules, especially in amino acids, which are the building blocks of proteins.
Structure: R-NH2
Properties: Acts as a base by accepting protons (H+).
Example: Found in amino acids such as glycine and alanine.
Carboxyl Group
The carboxyl group is a key functional group in organic acids, including amino acids and fatty acids.
Structure: R-COOH
Properties: Acts as an acid by donating protons (H+).
Example: Present in acetic acid and citric acid.
Carbonyl Group
The carbonyl group is found in aldehydes and ketones, which play important roles in metabolism and energy production.
Structure: Aldehyde: R-CHO; Ketone: R-CO-R'
Properties: Reacts with certain compounds to produce larger molecules.
Example: Glucose contains an aldehyde group; acetone is a simple ketone.
Hydroxyl Group
The hydroxyl group is characteristic of alcohols and is important for solubility and hydrogen bonding.
Structure: R-OH
Properties: Highly polar; may act as a weak acid; increases solubility in water.
Example: Ethanol and glycerol contain hydroxyl groups.
Phosphate Group
The phosphate group is essential in energy transfer and storage in biological systems, such as ATP.
Structure: R-O-PO32-
Properties: Stores large amounts of chemical energy; highly charged and polar.
Example: ATP (adenosine triphosphate) contains three phosphate groups.
Sulfhydryl Group
The sulfhydryl group is important in protein structure due to its ability to form disulfide bonds.
Structure: R-SH
Properties: Can form disulfide (S-S) bonds that contribute to protein structure.
Example: Cysteine contains a sulfhydryl group, which forms disulfide bridges in proteins.
Comparison Table: Functional Groups
The following table summarizes the main features of each functional group:
Functional Group | Structure | Compound Type | Main Properties |
|---|---|---|---|
Amino | R-NH2 | Amines | Acts as a base |
Carboxyl | R-COOH | Carboxylic acids | Acts as an acid |
Carbonyl | R-CHO (Aldehyde), R-CO-R' (Ketone) | Aldehydes/Ketones | Reacts to produce larger molecules |
Hydroxyl | R-OH | Alcohols | Highly polar, weak acid, increases solubility |
Phosphate | R-O-PO32- | Organic phosphates | Stores chemical energy |
Sulfhydryl | R-SH | Thiols | Forms disulfide bonds in proteins |
Additional info:
Functional groups determine the chemical reactivity and physical properties of organic molecules.
Disulfide bonds formed by sulfhydryl groups are crucial for the tertiary and quaternary structure of proteins.
Phosphate groups are central to energy transfer in cells, especially in nucleotides like ATP and DNA/RNA backbones.
