All cells are enclosed by a cell membrane, which is selectively permeable. Molecules can move into or out of cells by diffusion and active transport. Cells can gain or lose water by osmosis.
What are the two main components of cell membranes?
Proteins and cellulose
Cellulose and lipids
Phospholipids and proteins
A glucose molecule diffuses out of a cell through the selectively permeable cell membrane. What is this an example of?
The diagram shows three animal cells. Pairs of red circles represent oxygen molecules.
Between which two cells is there the highest oxygen concentration gradient?
One and two
Two and three
One and three
The diagram shows three plant cells and the solute concentrations of their cell solutions.
Between which cells will the movement of water by osmosis occur?
From three to one
From one to two
From one to three
What may happen to red blood cells placed in distilled (pure) water?
They may burst
They may become turgid
They may shrink
Which structure can prevent a plant cell from bursting when it gains water by osmosis?
What will happen when plant cells are placed in distilled (pure) water?
They will burst
They will become plasmolysed
They will become turgid
The diagram shows a cube of potato, (P), in a beaker containing a solution containing a very high sugar concentration (R)
After one hour, what will have happened to cube P?
It will have gained mass
It will have remained the same mass
It will have lost mass
What could cause a plant cell to become plasmolysed?
Gain of water
Loss of water
The vacuole swelling up
Which of the following processes requires energy to occur?