Condensation, hydrolysis and glycosidic bondsEdexcel International A Level Biology: Mind map

Exam questions on Condensation, hydrolysis and glycosidic bonds

1. Sucrose is the main sugar transported in the phloem of a sugar-cane plant. The plant makes sucrose in its leaves from two monosaccharides.
   Describe how a molecule of sucrose is formed from its two monosaccharides.2 marks
2. Milk contains the disaccharide lactose. A man with lactose intolerance has too little of the enzyme lactase in his small intestine, so lactose in milk is not digested properly.
   Explain how lactase breaks down lactose, referring to the bond and to water.2 marks
3. During germination, a barley seed releases amylase, which digests the starch stored in the seed. The embryo needs glucose for respiration. Starch is an unbranched polysaccharide in this example, made of glucose units joined by glycosidic bonds.
   Explain how amylase and maltase together convert starch into glucose.3 marks