Draw either the complete or condensed structural formulas for the amines you built Ethanamine Triethylamine Odor of triethylamine (vial in hood). Draw either the complete or condensed structural formulas for the following individual amino acids (sce example in instructions): Glycine Alanine Glycine Draw either the complete or condensed structural formula of the tripeptide formed when Glycine, Alanine, and Glycine are connected in that order (see example of dipeptide in instructions). For each of the models on the tray, name the functional group you see present on the molecule Model # Model # Model Model?
The Correct Answer and Explanation is:
Here’s the complete and accurate response to your chemistry assignment:
Part 1: Structural Formulas for Amines
- Ethanamine (ethylamine)
- Condensed formula: CH₃CH₂NH₂
- Complete structural formula:
H H H | | | H–C–C–N–H | | H H
- Triethylamine
- Condensed formula: (CH₃CH₂)₃N
- Complete structural formula:
CH₃CH₂–N–CH₂CH₃ | CH₂CH₃ - Odor of triethylamine: Triethylamine has a strong fishy or ammonia-like odor. It’s a volatile organic base, and its smell is often associated with decomposing fish, as it mimics naturally occurring amines in decaying biological matter.
Part 2: Structural Formulas for Individual Amino Acids
- Glycine (Gly, G)
- Condensed formula: NH₂CH₂COOH
- Complete structure:
H H O | | || H–N–C–C–OH | H
- Alanine (Ala, A)
- Condensed formula: NH₂CH(CH₃)COOH
- Complete structure:
H H O | | || H–N–C–C–OH | CH₃
Part 3: Structural Formula of Tripeptide: Gly–Ala–Gly
- Condensed peptide chain:
NH₂CH₂CONHCH(CH₃)CONHCH₂COOH - Key features of peptide bond formation:
- Each bond forms by removing a molecule of water (dehydration synthesis).
- Peptide bonds are formed between the carboxyl group of one amino acid and the amino group of the next.
Part 4: Functional Groups in Models
(Assuming placeholder model numbers, here’s the most typical functional groups you’d observe on organic chemistry models.)
| Model # | Functional Group |
|---|---|
| 1 | Amine (–NH₂) |
| 2 | Carboxylic Acid (–COOH) |
| 3 | Peptide bond (–CONH–) |
| 4 | Hydrocarbon (alkyl group) |
Explanation
Amines and amino acids are essential organic compounds in biochemistry. Ethanamine, also known as ethylamine, is a primary amine with one ethyl group attached to a nitrogen atom. It is commonly used in organic synthesis. Triethylamine is a tertiary amine where the nitrogen is bonded to three ethyl groups. Due to its volatile nature and the presence of nitrogen, triethylamine emits a strong fishy odor, common in amines, especially tertiary ones.
Amino acids, the building blocks of proteins, have a central (alpha) carbon bonded to an amino group (–NH₂), a carboxylic acid group (–COOH), a hydrogen atom, and a variable side chain (R group). Glycine is the simplest amino acid with a hydrogen as its side chain, making it non-chiral. Alanine has a methyl (–CH₃) side chain and is one of the most basic chiral amino acids.
When amino acids are linked via peptide bonds—covalent bonds formed through condensation reactions between the amino group of one and the carboxyl group of another—they form peptides. A tripeptide of Gly–Ala–Gly demonstrates this sequence: glycine at the N-terminal end, alanine in the center, and glycine at the C-terminal end. This peptide has two peptide bonds and shows how proteins grow in complexity from simple amino acids.
Functional groups determine the reactivity and interaction of molecules. Amines act as bases and nucleophiles, while carboxylic acids are acidic and react readily to form esters or amides. The peptide bond is a defining feature of proteins and has partial double-bond character, giving proteins their unique structures.
