A respiring yeast cell is in a liquid that contains dissolved oxygen and starch. At the start, there is no starch inside the cell. After 5 minutes, oxygen has moved into the cell, but no starch has entered it.
Which statement explains these observations?
Oxygen is moved in by active transport, which cannot move large molecules such as starch.
Oxygen moves in by osmosis, which moves small molecules across the membrane but not large ones.
Oxygen molecules can pass through the cell membrane, but starch molecules are too large to pass through it.
Oxygen moves in down its concentration gradient, but starch has no concentration gradient across the membrane.
140 exam-style questions on AQA GCSE Biology 1.3 Transport in cells, covering 1.3.1 Diffusion, 1.3.2 Osmosis, and 1.3.3 Active transport. Each one has a worked solution and a mark scheme showing where the marks go.