Botany MCQs for NEET — Practice Questions with Answers

Parenchyma is a living tissue in plants, consisting of cells with thin cell walls that are capable of cell division. It plays a key role in various physiological functions such as photosynthesis, storage, and tissue repair. In contrast, sclerenchyma, xylem vessels, and tracheids are typically composed of dead cells.

Collenchyma cells are a type of plant cell characterized by the uneven thickening of their cell walls, predominantly at the corners. This thickening is mainly composed of pectin along with cellulose, which provides flexibility and structural support to the plant parts.

Sclereids, also known as stone cells, are a type of sclerenchyma cell. They are typically found in various plant tissues, providing mechanical support and protection due to their thick, lignified cell walls. They are commonly found in fruits like pears and in the shells of nuts.

The cuticle is a waxy layer present on the surface of both leaves and stems. It serves to reduce water loss by evaporation and provides a barrier against pathogens. It is not present on roots as roots are responsible for water absorption.

Companion cells are specialized parenchyma cells found in the phloem of flowering plants. They are closely associated with sieve tube elements and help in the transport of sugars and other nutrients.

Sieve tube elements are characterized by the absence of a nucleus at maturity, which allows for more efficient transport of nutrients. The presence of companion cells helps to maintain the metabolic functions that the sieve tube elements cannot perform due to the absence of a nucleus.

Xylem parenchyma is the only living component in the xylem tissue. It plays a crucial role in the storage of nutrients and water, as well as the lateral transport of water and minerals.

Safranin is a biological stain used for coloring lignified cells. Lignin is a complex organic polymer found in the cell walls of many plants, making them rigid and woody. Safranin stains these cells red, which helps in identifying lignified tissues under a microscope.

Radial vascular bundles are typically found in roots. In radial vascular bundles, the xylem and phloem are arranged in an alternating manner on different radii. This arrangement is common in the roots of dicot and monocot plants, helping in the efficient transport of water, nutrients, and food.

Cucurbita stem shows bicollateral vascular bundles which produce outer and inner phloem but intraxylary phloem is absent.