Question

Write the chemical formula for each of the following compounds: (a) lysine (an amino acid): 6 carbon, 14 hydrogen, 2 nitrogen, and 2 oxygen atoms (b) methionine (an amino acid): 5 carbon, 11 hydrogen, 1 nitrogen, 2 oxygen, and 1 sulfur atom

Short answer

Lysine: \( C_6H_{14}N_2O_2 \); Methionine: \( C_5H_{11}NO_2S \).

Step-by-step solution

Identifying the Elements for Lysine

Lysine contains the elements: Carbon (C), Hydrogen (H), Nitrogen (N), and Oxygen (O). The quantities needed for each are: 6 Carbon, 14 Hydrogen, 2 Nitrogen, and 2 Oxygen atoms.

Writing the Chemical Formula for Lysine

Using the quantities from Step 1, the chemical formula for Lysine is constructed as follows: Begin with the symbol for each element followed by its corresponding subscript (quantity). This results in the formula: \( C_6H_{14}N_2O_2 \).

Identifying the Elements for Methionine

Methionine contains the elements: Carbon (C), Hydrogen (H), Nitrogen (N), Oxygen (O), and Sulfur (S). The quantities are: 5 Carbon, 11 Hydrogen, 1 Nitrogen, 2 Oxygen, and 1 Sulfur atom.

Writing the Chemical Formula for Methionine

Construct the chemical formula for Methionine by listing each element symbol followed by its respective subscript. This results in the formula: \( C_5H_{11}NO_2S \).

Key concepts

Amino Acids

Amino acids are organic compounds that serve as the building blocks of proteins. They play a crucial role in nearly every biological process. Each amino acid has a basic structure consisting of an amino group (\(\text{NH}_2\)), a carboxyl group (\(\text{COOH}\)), a hydrogen atom, and a unique side chain, often represented by R, that defines the specific characteristics of each amino acid.
Amino acids can be categorized into different types based on the properties of their side chains:

• Nonpolar and neutral: Side chains that are not attracted to water. Examples include alanine and valine.
• Polar but neutral: Side chains interact with water but are not charged, such as serine and threonine.
• Electrically charged: These side chains carry either a positive or negative charge, which facilitates interaction and bonding with other molecules. Examples include lysine and aspartic acid.

Amino acids are linked together in chains through peptide bonds, creating proteins. The sequence and structure of these amino acids dictate the specific function of the protein.

Lysine

Lysine is one of the essential amino acids, meaning it cannot be produced by the human body and must be obtained from dietary sources. Its primary function includes ensuring the proper growth and muscle turnover. Additionally, it aids in the body's absorption of calcium for bone health.
Lysine's chemical structure endears a longer side chain culminating in an amino group, making it a basic amino acid. This structure is represented chemically as: \[ C_6H_{14}N_2O_2 \]
A few key benefits of lysine include:

• Immune system support: Lysine plays a role in the production of antibodies to fight infections.
• Wound healing: It promotes the creation of collagen, a protein essential for skin and tissue repair.

Sources rich in lysine are typically animal-based foods such as:

• Red meat
• Eggs
• Cheese

Though people who follow a vegan diet can also obtain lysine by consuming soy products, legumes, and other protein-rich plants.

Methionine

Methionine is another essential amino acid crucial for various metabolic processes. As an essential amino acid, methionine must be ingested through food.
The distinct feature of methionine is the sulfur-containing thioether group in its molecular structure, denoted by the chemical formula:\[ C_5H_{11}NO_2S \]
This sulfur atom is crucial as it contributes to methionine's role in:*
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• Starting protein synthesis: Methionine is unique because it is the first amino acid in the synthesis of nearly all proteins, as it represents the start codon in the genetic code.
• Methylation: It assists in various methylation reactions, critical for DNA replication and the regulation of gene expression.

Dietary sources of methionine include:

• Turkey
• Pork
• Fish

These sources ensure that individuals obtain enough methionine for healthy physiological functioning. Methionine also helps detoxify harmful substances in the body by aiding cysteine production, another amino acid with antioxidant capabilities.