Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Transport in plants involves two main vascular tissues: and . transports water and minerals upwards, while translocates prepared food (glucose) to all parts of the plant.
Diffusion is the movement of molecules from a region of higher concentration to a region of lower concentration. In plants, and move via diffusion through stomata.
Osmosis is the diffusion of water () molecules across a semi-permeable membrane from a region of higher water concentration (dilute solution) to a region of lower water concentration (concentrated solution).
Active Transport is the movement of molecules (like mineral ions) against a concentration gradient, requiring energy in the form of .
Transpiration is the loss of water in the form of water vapor from the aerial parts of the plant (mainly leaves). It creates a 'Transpiration Pull' which helps in the upward movement of water, known as the Ascent of Sap.
Root Pressure is the inward pressure exerted by the root cells that pushes the water into the vessels and helps it rise to a certain height.
The consists of four types of cells: Tracheids, Vessels (non-living), Xylem Parenchyma (living), and Xylem Fibres (non-living).
The consists of Sieve tubes, Companion cells, Phloem Parenchyma, and Phloem Fibres.
📐Formulae
💡Examples
Problem 1:
A plant cell is placed in a solution with a higher concentration of solutes than its own cytoplasm. What process will occur, and what will be the state of the cell?
Solution:
Exosmosis will occur, and the cell will become flaccid (plasmolysis).
Explanation:
Because the external solution is hypertonic (lower concentration), water moves out of the cell across the semi-permeable membrane via osmosis, causing the protoplast to shrink away from the cell wall.
Problem 2:
Why is required for the uptake of minerals like and from the soil into the root hairs?
Solution:
The uptake occurs via Active Transport.
Explanation:
The concentration of mineral ions in the soil is often lower than the concentration inside the root cells. To move these ions against the concentration gradient, the cell must expend energy in the form of (Adenosine Triphosphate).
Problem 3:
Explain the role of the 'Transpiration Pull' in a tall Eucalyptus tree.
Solution:
It facilitates the Ascent of Sap over long distances.
Explanation:
As evaporates from the leaf surface via stomata, it creates a negative pressure (suction) in the . This suction force is transmitted down to the roots, pulling a continuous column of water molecules (held together by cohesive and adhesive forces) upwards.