Cells Topic
What Happens When a Cell Part is Removed?
This science revision note aims to help your child
– Understand the difference between the cell wall and cell membrane
– Predict and explain what happens when a cell part is removed.
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Cell A was placed into a mixture of Substance P and Substance Q. After a few minutes, Cell A was observed under a microscope and only Substance P was found inside.
Afterwards, Part X was removed from Cell A and Cell A was placed back into an identical mixture of Substance P and Substance Q.
After a few minutes, Cell A was observed under a microscope again. Which substance(s) will be found inside Cell A now? Explain your answer. (2m)
STEP 1
Identify Part X that is removed.
Part X is the cell wall.
STEP 2
What is the function of Part X? Does it affect the movement of substances moving in and out of the cell?
The function of the cell wall is to support the cell and gives the cell its shape. It does not affect the movement of substances moving in and out of the cell.
STEP 3
Which part of Cell A controls the movement of substances in and out of the cell? Has this part been removed?
The cell membrane controls the movement of substances in and out of the cell and it is still present.
FINALLY, put your answer together
Question: Which substance(s) will be found inside Cell A now? Explain your answer. (2m)
Answer:
Only Substance P will be found inside Cell A.
The part that has been removed is the cell wall. (0.5m) The cell membrane is present. (0.5m) The cell membrane, not the cell wall, controls the movement of substances in and out of the cell. Hence, the cell membrane allows substance P to enter the cell but not substance Q. (1m)
Note: Compare the relevant functions of each cell part. That is the function of the movement of substances in and out of the cell.
Common mistakes
Wrong answer: Both Substance P and Q can enter Cell A. The cell wall has been removed, which allows all substances to enter the cell.
The cell wall does not control which substances can enter or leave the cell. Only the cell membrane can do so. Hence, removing the cell wall does not affect the substances able to enter the cell.
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Andy Ling
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