A student mixes yeast with three different carbohydrates in water. The student measures the volume of carbon dioxide produced in 20 minutes. Table
| Carbohydrate | Volume of carbon dioxide produced in cm3\text{cm}^3cm3 |
|---|---|
| glucose | 24.0 |
| sucrose | 18.5 |
| starch | 1.5 |
| The student concludes that yeast cannot use starch for respiration as quickly as it uses glucose. | |
| Which statement explains this result? |
Starch is a polymer and must first be broken down into glucose monomers.
Starch is a monomer and must first be joined to make glucose polymers.
Starch contains no glucose, so yeast cannot use it in respiration at all.
Starch is broken down into amino acids, which yeast cannot respire.
113 exam-style questions on OCR GCSE Biology 1.3 Respiration, covering 1.3.1 Cellular respiration supplies ATP, 1.3.2 Aerobic and anaerobic respiration, 1.3.3 Sugars and carbohydrates, 1.3.4 Amino acids and proteins, and 1.3.5 Fatty acids and lipids. Each one has a worked solution and a mark scheme showing where the marks go.