Question

In phloem, organic compounds flow through a. collenchyma cells c. vessels b. sieve elements d. tracheids

Short answer

In phloem, organic compounds flow through sieve elements.

Step-by-step solution

Understand the Question

The question asks which type of cells in the phloem allow for the flow of organic compounds. This is a multiple-choice question with four options: collenchyma cells, vessels, sieve elements, and tracheids.

Recall Phloem Structure

Phloem is a type of tissue in plants responsible for transporting organic compounds, especially sugars, from where they are made in the plant to where they are used or stored. Understanding which parts of phloem are responsible for this transport is key.

Identify Functions of Given Options

- **Collenchyma cells**: Provide structural support and are not involved in transporting organic compounds. - **Vessels**: Part of the xylem, primarily involved in the transport of water. - **Sieve elements**: Specialized cells forming tubes for sugar and nutrient transport in the phloem. - **Tracheids**: Also part of the xylem, involved in water conduction.

Select the Correct Option

Based on the roles of these cell types, sieve elements are the cells in the phloem responsible for transporting organic compounds. Thus, the correct choice is option b: sieve elements.

Key concepts

Sieve Elements

Sieve elements are essential components of the plant's phloem, playing a crucial role in the transport system of organic compounds. Think of them as the highways for sugars and nutrients within a plant.

Unlike other plant cells, sieve elements are specifically adapted for efficient transport. They are elongated and join end-to-end to form long tubes. These tubes are known as sieve tubes. At their ends, they possess sieve plates, which are porous regions that allow materials to pass through easily.

One interesting aspect of sieve elements is that they lack a nucleus and have fewer organelles. This unique feature maximizes space for transporting materials and ensures minimal resistance during flow. However, because they lack essential cellular mechanisms, they rely on companion cells for metabolic support.

In summary, the sieve elements are specialized and efficient structures ensuring the smooth and effective movement of food and nutrients from the leaves to other parts of the plant.

Plant Tissue

Plant tissue is an organized collection of cells that serve one or several functions in a plant. Different plant tissues work together to maintain the plant's growth, structure, and function.

The primary types of plant tissue include:

• Dermal Tissue: This covers the outer surface of a plant and protects it from the environment.
• Vascular Tissue: A transportation network that includes xylem and phloem. Xylem is responsible for water transport, while phloem moves organic compounds such as sugars.
• Ground Tissue: Provides support and storage and is involved in photosynthesis.

Among these, phloem is essential for transporting organic materials. The phloem consists of different cells, including sieve elements, companion cells, phloem parenchyma, and fibers. Together, they ensure nutrients are delivered efficiently throughout the plant.

Understanding plant tissue is key to appreciating how plants function, enabling them to grow, reproduce, and survive in diverse environments.

Organic Compounds

Plants produce and transport various organic compounds crucial for growth and metabolic functions. These compounds primarily include sugars, amino acids, hormones, and many other molecules derived from photosynthesis.

One of the major organic compounds in plants is glucose, a simple sugar formed during photosynthesis. Glucose is vital for energy and serves as a building block for more complex carbohydrates, like sucrose and starch.
Sucrose, in particular, is transported through the phloem to various parts of the plant for energy storage or immediate use.

Besides sugars, plants also transport amino acids, which are the building blocks of proteins, necessary for growth and repair. Hormones, such as auxins and gibberellins, are also considered organic compounds. They regulate various plant processes, including growth, flowering, and fruit development.

The ability of plants to produce and effectively transport these organic compounds via sieve elements in the phloem is fundamental to their survival and capacity to flourish in their environments.