During water and solute transport across a plant root, water moves from the soil to the xylem via the apoplastic and symplastic pathways.
Which of the following statements correctly describes a feature of these transport pathways?
Water moving through the symplastic pathway experiences less resistance to flow than water moving through the apoplastic pathway because cytoplasm has a lower viscosity than cellulose cell walls.
Active pumping of mineral ions into the xylem by endodermal cells lowers the water potential of the xylem, driving the entry of water into the xylem by osmosis.
The Casparian strip contains a waterproof band of suberin that blocks the symplastic pathway, forcing water molecules to enter the apoplastic pathway at the endodermis.
Because plasmodesmata are membrane-lined channels, water molecules moving via the symplastic pathway must cross a plasma membrane at each cell-to-cell boundary.
28 exam-style questions on OCR A A Level Biology Transport in plants. Each one has a worked solution and a mark scheme showing where the marks go.