Monosaccharides and disaccharidesAQA A-Level Biology: Mind map

Exam questions on Monosaccharides and disaccharides

1. Carbohydrates in the human diet include the monosaccharides glucose, fructose and galactose and the disaccharides maltose, sucrose and lactose.
   Name the bond that joins two monosaccharides in a disaccharide and name the small molecule that is released when it forms.2 marks
2. A technician has a clear, colourless solution that is either sucrose or maltose. She heats a sample with Benedict's reagent in a boiling water bath and the mixture stays blue.
   The repeated test gives a brick-red precipitate. Explain this result.2 marks
3. Glucose, galactose and fructose all have the molecular formula C₆H₁₂O₆. Glucose exists as two isomers, α-glucose and β-glucose. Maltose is a disaccharide made from two α-glucose molecules. Relative formula masses: maltose 342, glucose 180.
   Explain what is meant by isomers, and describe how α-glucose differs from β-glucose.3 marks