Chapter 22.1, Problem 3MI

Summary Introduction

To classify:

The given vocabulary words as plant cell or plant tissue and then describe them.

Introduction:

A cell is the structural, functional, and biological unit of all living organisms. It is smallest unit for life. A cell can be prokaryotic or eukaryotic. Eukaryotic cells contain membrane bound cell organelles that help in functioning of cellular machinery by carrying out biochemical reactions.

Explanation of Solution

Plant cells act as building blocks for plants. These cells contain chloroplast, where photosynthesis occurs. It is an important process in plants for making food, by using sunlight, water, and carbon dioxide.

Plant cells −

Collenchyma cells − They are a kind of plant cells. These cells are elongated and contain irregular thick cell walls. These walls provide structure and support to the cell. The cell wall of collenchyma cell is made of cellulose and pectin. Collenchyma cells are found below the epidermis, in leaf veins, and young stem’s outer layer.

Companion cell − This cell type is found in flowering plants’ phloem. All companion cells are associated with sieve elements. The function of a companion cell is to load and unload sugar molecules into sieve element.

Guard cells − These cells are found in the epidermis of leaves, organs that control gas exchange, and stems.

Parenchyma cells − These are plant cells that cannot undergo cell division further. Newly formed parenchyma cells contain dense cytoplasm and small vacuoles.

Sclerenchyma cells − These plant cells function to support plant as they are strong and thick. Due to much thick cell walls these cells does not perform much activities.

Sieve tube members − These plant cells that do not contain nucleus. They function to transport carbohydrates across the plant.

Tracheid - It is an elongated cell found in the xylem of vascular plants. The function of tracheid is to conduct water and provide mechanical support.

Vessel element − It is a type of cell that is found in xylem that helps in conduction of water across the plant.

Plant tissues −

Cork cambium − It is a plant tissue found in vascular plants in epidermis. It is lateral meristem that is responsible for secondary growth of the plant.

Epidermis − It is the layer of cells that cover the stem, leaf, flower, root, seeds, and fruit. Epidermis is covered with waxy cuticle that protects plant from infection, injury, and water loss.

Ground tissue − It is a plant tissue that arises from the ground meristem. It is found in the cortex, pith, and pericycle of plant.

Meristem − It is a plant tissue that contains undifferentiated cells. Cells in meristem have the ability to develop into other tissues and organs.

Phloem − It is the vascular tissue found in plants. It helps in the transport of sugars from source tissue to sink tissues.

Vascular cambium − It is a tissue in plants that is mainly responsible for growth of stems and roots.

Xylem − It is an important plant tissue that conducts water across the plant.