What of the following statement is correct regarding phloem of a plant?
I. The translocation in phloem is achieved by utilizing energy.
II. Material are transferred into phloem tissue using energy from ATP.
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3: Both I and II.
Explanation:
The primary function of phloem tissue in plants is to transport food (sugars/sucrose) prepared by the leaves to other parts of the plant. This process differs significantly from that of xylem.
Energy Utilization (Statements 1 and 2): In xylem, water transport is driven by physical forces (such as transpiration pull); however, translocation in phloem is an active process. It requires energy in the form of ATP (Adenosine Triphosphate) to transport food.
The Process: When substances like sucrose are loaded into the phloem tissue (sieve tubes) using the energy from ATP, the osmotic pressure within that tissue increases. This causes water to enter the phloem, and the resulting pressure pushes the food toward tissues with lower pressure.
Additional Facts:
- Bidirectional Transport: In phloem, food can move in both upward and downward directions (from leaves to roots, or from stored food in roots to buds).
- Components of Phloem: It is composed of four types of cells: sieve tubes, companion cells, phloem parenchyma, and phloem fibers.
- Xylem vs. Phloem: Xylem is dead tissue (with the exception of fibers) and transports only water and minerals, whereas phloem is primarily living tissue and transports food.
Potential Questions for Upcoming Exams:
Question: What is the process of food transport in plants called?
Answer: Translocation.
Question: Which component of the phloem is primarily composed of dead cells?
Answer: Phloem fibers.
Question: What is the primary force responsible for water transport in the xylem?
Answer: Transpiration pull.