4.1 Biological Molecules

This section focuses on the chemical composition of the major biological molecules: carbohydrates, fats, and proteins.

Carbohydrates

Carbohydrates are organic compounds composed of carbon, hydrogen, and oxygen. The general formula for carbohydrates is $C_n H_m O_p$, where n, m, and p represent the number of carbon, hydrogen, and oxygen atoms, respectively.

The key elements are:

• Carbon (C)
• Hydrogen (H)
• Oxygen (O)

Fats (Lipids)

Fats, also known as lipids, are primarily composed of carbon, hydrogen, and oxygen. However, they contain a much higher proportion of hydrogen compared to carbohydrates. The general formula for lipids is also $C_n H_m O_p$, with a significantly higher ratio of hydrogen to oxygen.

The key elements are:

• Carbon (C)
• Hydrogen (H)
• Oxygen (O)

Proteins

Proteins are complex organic molecules made up of amino acids. Each amino acid contains carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. The general formula for an amino acid is $C_n H_m N_p O_q S_r$, where n, m, p, q, and r represent the number of carbon, hydrogen, nitrogen, oxygen, and sulfur atoms, respectively.

The key elements are:

• Carbon (C)
• Hydrogen (H)
• Oxygen (O)
• Nitrogen (N)
• Sulfur (S) (in some amino acids)

Summary Table