Biological molecules

What are the chemical elements that make up carbohydrates?

Carbon, Hydrogen, Oxygen

What are the main roles of carbohydrates in living organisms?

Immediate source of energy, substrate for respiration, structural support, conversion to organic compounds, formation of nucleic acids, synthesis of lubricants, and synthesis of nectar.

What are the chemical elements that make up fats?

Carbon, Hydrogen, Oxygen

What are the main roles of fats in living organisms?

Insulation, long-term energy storage, solvent for fat-soluble vitamins, essential part of cells, and reducing water loss.

What are the chemical elements that make up proteins?

Carbon, Hydrogen, Oxygen, Nitrogen

What are the main roles of proteins in living organisms?

Synthesis of new cytoplasm, growth and repair of cells, synthesis of enzymes and hormones, and formation of antibodies.

How do you test for the presence of starch?

Using iodine in potassium iodide solution; a blue-black color indicates presence of starch.

How do you test for reducing sugars?

Using Benedict's solution and placing it in a boiling water bath; color change to green, yellow, or red indicates presence of reducing sugars.

How do you test for proteins?

Using biuret solution (CuSO4 + NaOH); a color change from blue to violet indicates presence of proteins.

How do you test for fats?

Using ethanol; a white emulsion indicates presence of fats.

What do carbohydrates form?

Glucose forms cellulose, glycogen, and starch.

What do proteins form?

Amino acids form polypeptides and proteins.

What do fats form?

Glycerol and fatty acids form lipids such as fats.

What is the role of an enzyme's active site?

It allows the enzyme to bind specifically to its substrate and form an enzyme-substrate complex.

What happens in the enzyme-substrate complex?

The substrate binds to the active site, and a chemical reaction occurs, converting substrate to products.

What effect does temperature have on enzyme activity?

Below optimum temperature, enzyme activity decreases; beyond optimum temperature, enzymes may denature.

What effect does pH have on enzyme activity?

Below or beyond optimum pH, enzyme activity is low and enzymes may denature.

What is the 'lock and key' hypothesis in enzymology?

Enzymes have a specific shape that allows only substrates with complementary shapes to bind to the active site.