Neco 2024 Biology Question 3

A group of students investigated the effect of temperature on the rate of starch digestion by amylase. The experiment was set up as follows: - 10 mL of 1% starch solution was mixed with 5 mL of amylase solution (enzyme concentration kept constant). - The mixture was incubated for 10 minutes at three different temperatures: 20°C, 30°C, and 40°C. - After incubation, 2 mL of the mixture was withdrawn and the iodine test was performed. The intensity of the blue‑black colour was measured using a spectrophotometer (wavelength 620 nm) and recorded as absorbance values. The absorbance recorded for each temperature is shown in the table below. | Temperature (°C) | Absorbance (A) | |------------------|----------------| | 20 | 0.80 | | 30 | 0.45 | | 40 | 0.20 | A blank containing only distilled water gave an absorbance of 0.00. A standard solution of 1% starch gave an absorbance of 1.00, which is taken as 100 % starch concentration. Using the data above, answer the following questions: