A student wanted to find out if using pectinase allows more juice to be extracted from apples. She took two apples (of the same kind) and cut them up into small pieces,
each roughly cube-shaped with sides of about 5 mm. She put half of the pieces into one
beaker, and the other half into another. She then added 2 cm of pectinase to one
beaker and 2 cm of water to the other. She left the beakers to stand for 20 minutes.
She then filtered the juice from the apple pieces and measured its volume. She found
that she obtained 14 cm of juice from the apples to which pectinase had been added,
and 7 cm of juice from the apples to which water had been added.
I
Answer the following questions:
1. What is pectinase?
• Pectinase is found in bacteria and plants. Pectinase is an enzyme that breaks down the
substances that hold the cell walls of the apple cells
together. This
makes it easier to
squeeze out more of the juice.
2. Suggest a hypothesis that is being tested by this investigation.
.
3. State 4 variables that the student should have kept constant in her investigation.
4. Suggest two ways in which she could have increased the yield from the apple pieces in both
beakers
5. Suggest one way in which she could increase the reliability of her results.