1.2 Elements Of Life
Identify the three most common elements found in all four classes of biological macromolecules.
Carbon, hydrogen, and oxygen are the three most prevalent elements used to build carbohydrates, proteins, lipids, and nucleic acids.
Predict the effect on macromolecule synthesis if a plant is grown in soil lacking phosphorus. Justify your prediction.
The plant would be unable to synthesize adequate phospholipids and nucleic acids because both require phosphorus — phospholipids need phosphate in their head group, and nucleic acids need phosphate in their sugar-phosphate backbone. Carbohydrate and most other lipid synthesis would remain unaffected because those molecules do not contain phosphorus.
Explain why sulfur deficiency would impair protein function but not carbohydrate function.
Sulfur is incorporated into certain amino acids that form proteins, so a lack of sulfur would prevent proper protein assembly. Carbohydrates are composed only of carbon, hydrogen, and oxygen, so their synthesis does not depend on sulfur availability.