BISC Bioinformatics Quiz: MCQ!

Explanation
Roots and shoots lengthen through activity at apical meristems. Apical meristems are found at the tips of roots and shoots and are responsible for the primary growth of plants. They contain undifferentiated cells that continuously divide, producing new cells that differentiate into various tissues, allowing for the elongation and growth of roots and shoots. Lateral meristems, such as the vascular cambium and cork cambium, are responsible for secondary growth and the thickening of stems, but they do not contribute to the lengthening of roots and shoots.

Explanation
In many plant species, older roots and stems thicken by activity at both the cork cambium and the vascular cambium. The cork cambium is responsible for the production of cork cells, which form the outer protective layer of the stem or root. The vascular cambium, on the other hand, is responsible for the production of secondary xylem and phloem, which contribute to the increase in girth or thickness of the plant. Therefore, both the cork cambium and the vascular cambium play a role in the thickening of older roots and stems in plants.

Explanation
Xylem is responsible for conducting water and minerals from the roots to the rest of the plant. It consists of long, tubular cells that are interconnected and form a network throughout the plant. On the other hand, phloem is responsible for conducting sugars, produced in the leaves through photosynthesis, to other parts of the plant. It consists of sieve tubes and companion cells that work together to transport the sugars. Therefore, the correct answer is Xylem; phloem.

Explanation
Mesophyll refers to the internal tissue of a plant leaf that contains chloroplasts, which are responsible for photosynthesis. Therefore, the correct answer is "photosynthetic cells" as it accurately describes the composition of the mesophyll tissue.

Explanation
Collenchyma cells, sieve tubes, and companion cells are alive in the mature tissue. Collenchyma cells are elongated and provide support to the plant. Sieve tubes are part of the phloem and are responsible for transporting sugars and other organic molecules. Companion cells are closely associated with sieve tubes and provide metabolic support for their function.

Explanation
Phloem is responsible for the transport of organic compounds, such as sugars and amino acids, throughout the plant. Sieve tubes are the main components of phloem and are specialized for the efficient transport of these compounds. They are long, cylindrical cells with perforated end walls called sieve plates, allowing for the flow of sap containing organic compounds. The other options, collenchyma cells, vessels, and tracheids, are all types of cells involved in the transport of water and minerals in the xylem, not in the phloem. Therefore, the correct answer is sieve tubes.

Explanation
Xylem and phloem are vascular tissues. Vascular tissues are responsible for the transport of water, nutrients, and sugars throughout the plant. Xylem transports water and minerals from the roots to the rest of the plant, while phloem transports sugars and other organic compounds from the leaves to the rest of the plant. Ground tissue, on the other hand, is responsible for functions such as photosynthesis, storage, and support. Dermal tissue is the outer protective covering of the plant. Therefore, the correct answer is vascular.

Explanation
Tree rings occur when environmental conditions influence xylem cell size. The growth of tree rings is influenced by factors such as temperature, precipitation, and soil conditions. These environmental conditions affect the size of xylem cells, which are responsible for transporting water and nutrients throughout the tree. In favorable conditions, the xylem cells grow larger, resulting in wider tree rings. Conversely, in unfavorable conditions such as drought, the xylem cells may be smaller, leading to narrower tree rings. By studying tree rings, scientists can gain insights into past environmental conditions and climate patterns.

Explanation
The correct answer is periderm and phloem. The periderm is the outer protective layer of the bark, while the phloem is responsible for transporting sugars and other nutrients throughout the plant. Both of these components are essential for the functioning and protection of the plant.