What is a sieve-tube element? a. the sugar-conducting cell found in phloem b. the widened, perforation-containing, water-conducting cell found only in angiosperms c. the nutrient- and water-absorbing cell found in root hairs d. the nucleated and organelle-rich support cell found in phloem

Verified step by step guidance

1. Step 1: Understand the question. The question is asking for the definition of a sieve-tube element in the context of plant biology.
2. Step 2: Recall that sieve-tube elements are part of the phloem tissue in plants, which is responsible for transporting sugars and other nutrients produced in the leaves to other parts of the plant.
3. Step 3: Compare this information with the provided options. Option a states that a sieve-tube element is the sugar-conducting cell found in phloem, which aligns with our understanding of the role of sieve-tube elements.
4. Step 4: Review the other options to confirm that they do not accurately describe sieve-tube elements. Option b describes a type of cell found only in angiosperms, but sieve-tube elements are found in all vascular plants, not just angiosperms. Option c describes a cell found in root hairs, which is not where sieve-tube elements are located. Option d describes a cell that is nucleated and rich in organelles, but sieve-tube elements are actually lacking in these features.
5. Step 5: Based on this analysis, we can conclude that the correct answer is option a: a sieve-tube element is the sugar-conducting cell found in phloem.

Key Concepts

Sieve-Tube Elements

Sieve-tube elements are specialized cells in the phloem of vascular plants responsible for the transport of sugars and other organic nutrients. They are elongated cells that lack a nucleus and organelles, allowing for efficient flow of sap. These cells are connected end-to-end, forming long tubes that facilitate the movement of photosynthates from source to sink tissues.

Phloem

Phloem is one of the two types of vascular tissue in plants, the other being xylem. It is primarily responsible for the transport of organic compounds, particularly sugars produced during photosynthesis, from the leaves to other parts of the plant. Phloem consists of various cell types, including sieve-tube elements and companion cells, which work together to ensure efficient nutrient distribution.

Angiosperms

Angiosperms, or flowering plants, are a diverse group of plants characterized by the presence of flowers and seeds enclosed within a fruit. They represent the largest group of plants and have evolved complex structures for reproduction and nutrient transport, including specialized phloem cells like sieve-tube elements. Understanding angiosperms is crucial for recognizing the significance of sieve-tube elements in plant biology.