Biological molecules and enzymes

© UCLES 2025 5090/11/O/N/25 8 Which diagram correctly links the carbohydrates made as a result of photosynthesis with their uses? used in respiration for transport builds cell walls an energy store sucrose starch glucose cellulose A used in respiration for transport builds cell walls an energy store sucrose starch glucose cellulose B used in respiration for transport builds cell walls an energy store sucrose starch glucose cellulose C used in respiration for transport builds cell walls an energy store sucrose starch glucose cellulose D 5

© UCLES 2025 5090/11/O/N/25 [Turn over 21 The table shows the concentration of five substances in the blood entering the kidney, in fluid entering the nephron and in the urine. substance concentration / mg per dm 3 blood entering the kidney fluid entering the nephron urine urea 0.4 20.0 20.0 glucose 1.5 1.5 0.0 amino acids 0.8 0.8 0.0 ions 8.0 8.0 16.5 protein 82.0 0.0 0.0 Which substances are totally reabsorbed into the blood from the nephron? A amino acids and glucose B glucose and ions C protein and amino acids D protein and glucose 12

22 The graph shows blood glucose concentration over 6 hours in a day. 0 1 2 3 time / hours 4 5 6 20 15 10 5 0 blood glucose concentration / arbitrary units What is the set point for blood glucose concentration shown by this graph? A 5 arbitrary units B 10 arbitrary units C 15 arbitrary units D 20 arbitrary units

© UCLES 2025 5090/11/O/N/25 35 An investigation is done to find out how effective different biological washing powders are at digesting protein. Four equal-sized cubes of cooked egg white (protein) are cut and their masses measured. The cubes of protein are then placed in test-tubes containing 10 cm 3 of solutions of four different biological washing powders of the same concentration. The cubes of protein are left in the solutions at room temperature. After 24 hours, the cubes of protein are removed from the test-tubes and their masses remeasured. biological washing powder mass of cube of prot

36 Which enzyme is added to fruit to aid juice production? A lactase B lipase C pectinase D protease

4 Globulin is a substance that can be detected by the biuret test. Which type of substance is globulin? A fat B oil C protein D reducing sugar

5 Cellulose and glucose are carbohydrates. Cellulose is a large molecule made from a long chain of smaller glucose molecules. One cellulose molecule is 0.01 mm long. One glucose molecule is 0.001  m long. How many glucose molecules are found in this cellulose molecule? A 1  10 2 B 1  10 3 C 1  10 4 D 1  10 5