CIE iGCSE Co-Ordinated Science B3.2 Osmosis Exam Style Questions Paper 1
Question
The diagram shows the stages of an experiment.
A piece of potato with a mass of 10.0 g is placed in a beaker with a dilute sugar solution. After 30 minutes, the potato is carefully dried and its mass is now 10.4 g. Which statement is a correct explanation for the increase in mass?
A. Sugar has moved into the cells of the potato by osmosis.
B. Sugar has moved out of the cells of the potato by osmosis.
C. Water has moved into the cells of the potato by osmosis.
D. Water has moved out of the cells of the potato by osmosis.
▶️Answer/Explanation
Answer: C. Water has moved into the cells of the potato by osmosis.
Explanation: Osmosis is the movement of water molecules from a region of higher water potential (dilute solution) to a region of lower water potential (concentrated solution) through a partially permeable membrane. In this case, the dilute sugar solution has a higher water potential than the potato cells, so water moves into the potato cells, causing the mass to increase.
Question
Starch is mixed with saliva and placed into a bag made of a partially permeable membrane. The bag is placed into a tube filled with water, as shown.
After one hour, sugar molecules are found in the water outside the bag.
Which process has taken place inside the bag?
(A) assimilation
(B) digestion
(C) egestion
(D) ingestion
▶️Answer/Explanation
Ans: B
Question
The photographs show some onion cells before and after being placed in a concentrated solution of glucose.
What explains the appearance of the onion cells after placing them into the concentrated solution of glucose?
(A) Glucose has entered the cells by osmosis.
(B) Glucose has left the cells by diffusion.
(C) Water has entered the cells by diffusion.
(D) Water has left the cells by osmosis.
▶️Answer/Explanation
Ans: D