2013 The diagrams below show two cells. Marks B Q1 (b) i &ii 1 (i) The cell is placed in a hypertonic solution. Describe the appearance of the cell after one hour. (ii) Explain why the animal cell would stay the same size when it is placed in an 2 isotonic solution. Question Acceptable Answer Not acceptable Negates Mark 1 (b) i Vacuole/cytoplasm shrunken single It/cell 1 Membrane/cytoplasm pulled words eg shrinks away shrunken from wall/cytoplasm Plasmolysis concentrated Plasmolysed/flaccid ii no net water movement/ Nothing Any 1 water/osmosis in and out happens reference Equal (water/salt) concentration Water does not to inside and out/ no concentration move cell wall gradient in or out Solution moving Water/salt equal 1
2013 B Q1 (b) i &ii The diagrams below show two cells. Marks (i) The cell is placed in a hypertonic solution. Describe the appearance of the cell after one hour. 1 (ii) Explain why the animal cell would stay the same size when it is placed in an isotonic solution. 2 Question Acceptable Answer Not acceptable Negates Mark 1 (b) i Vacuole/cytoplasm shrunken Membrane/cytoplasm pulled away from wall/cytoplasm concentrated Plasmolysed/flaccid single words eg shrunken Plasmolysis It/cell shrinks 1 ii no net water movement/ water/osmosis in and out Equal (water/salt) concentration inside and out/ no concentration gradient Nothing happens Water does not move in or out Solution moving Water/salt equal Any reference to cell wall 1 1
Biology-N5-Past-Paper-Questions-Cell-Biology1.docx