Biological molecules

What chemical elements are present in carbohydrates, proteins, and lipids?

Carbohydrates: carbon, hydrogen, oxygen; Proteins: carbon, hydrogen, oxygen, nitrogen (sometimes sulfur); Lipids: carbon, hydrogen, oxygen.

What is the structure of carbohydrates, proteins, and lipids?

Carbohydrates: made from simple sugars (e.g., glucose); Proteins: made from amino acids; Lipids: made from fatty acids and glycerol.

How can you test food samples for biological molecules?

Use food tests: Glucose: Benedict's test; Starch: Iodine solution; Protein: Biuret test; Fat: Ethanol emulsion test.

What is the role of enzymes in biological systems?

Enzymes are biological catalysts that speed up metabolic reactions without being used up.

How does temperature affect enzyme activity?

Enzymes work best at their optimum temperature. Too high: enzymes denature; too low: slow reaction due to reduced kinetic energy.

How can temperature changes be investigated in enzyme activity?

By measuring reaction rate (e.g. starch breakdown) at different temperatures and observing changes in speed or completeness of reaction.

How does pH affect enzyme activity?

Changes in pH can alter the shape of the enzyme's active site, affecting its ability to bind substrates.

How can pH changes be investigated in enzyme activity?

By using buffer solutions of different pH levels and observing reaction rates (e.g. enzyme breaking down hydrogen peroxide or starch).