Biology: Macromolecules and Tests

This video from IGCSE Study Buddy covers topic 4 on biological molecules, focusing on carbohydrates, fats, proteins, and DNA. It explains the structure and function of these molecules, including food tests for identifying starch, sugars, proteins, fats, and vitamin C. The video concludes with a summary of DNA structure and base pairing.

Which of the following elements is found in proteins but not in carbohydrates or fats?

• Carbon

• Oxygen

• Hydrogen

• Nitrogen

What is the simplest form of carbohydrates known as?

• Disaccharides

• Polysaccharides

• Oligosaccharides

• Monosaccharides

Which of the following is a polysaccharide formed by glucose molecules?

• Maltose

• Sucrose

• Starch

• Fructose

What are the basic units that make up fats?

• Amino acids

• Fatty acids and glycerol

• Nucleotides

• Monosaccharides

How many different amino acids are there that can form proteins?

• 40

• 30

• 20

• 10

What color change indicates the presence of starch when iodine is added?

• Purple to pink

• Green to yellow

• Orange to blue-black

• Blue to red

Which solution is used to test for reducing sugars?

• Iodine

• Benedict's solution

• Ethanol

• Biuret solution

What indicates a positive test for proteins using Biuret solution?

• Color change from orange to pink

• Color change from yellow to blue

• Color change from red to green

• Color change from blue to violet

What is the structure of DNA described as?

• Quadruple helix

• Triple helix

• Double helix

• Single helix

Which base pairs with adenine in DNA?

• Guanine

• Cytosine

• Uracil

• Thymine