Chapter 20, Problem 9Q

A.

Summary Introduction

To examine: Whether the statement “Gap junctions connect the cytoskeleton of one cell to that of a neighboring cell or to the extracellular matrix” is correct or incorrect.

Introduction: Cytoskeleton is the structure of small fibrils inside the cells that maintain the shape and rigidity of the native cell. Extracellular matrix is a non-cellular component that is made up of proteins and glycosaminoglycan. Gap junctions function as the gateway for regulating the influx and efflux of molecules and change their structure according to the flow of ion molecules whenever required. Gap junctions play an important role in regulating the permeability of the cell wall.

B.

Summary Introduction

To examine: Whether the statement “A wilted plant leaf can be likened to a deflated bicycle tire” is correct or incorrect.

Introduction: Wilting of the plant leaves refers to the loss of rigidity of the leaf and as a result it droops.

C.

Summary Introduction

To examine: Whether the statement “Because of their rigid structure, proteoglycans can withstand a large amount of compressive force” is correct or incorrect.

Introduction: Proteoglycans are the proteins that appear differently in structure as well as composition from the others and are covalently linked to the glycosaminoglycan (GAGs-negatively charged polysaccharides) to form a core protein.

D.

Summary Introduction

To examine: Whether the statement “The basal lamina is a specialized layer of extracellular matrix to which sheets of epithelial cells are attached” is correct or incorrect.

Introduction: Epithelial cells line the surfaces of the body. The layer of extracellular matrix secreted by the epithelial cells is called as basal lamina.

E.

Summary Introduction

To examine: Whether the statement “Epidermal cells in the skin are continually shed and are renewed every few weeks; for a tattoo to be long-lasting, it is therefore necessary to deposit pigment below the epidermis” is correct or incorrect.

Introduction: Skin is the outermost covering of the body and is consists of the epidermis and the dermis. Epidermis is shed from the skin frequently.

F.

Summary Introduction

To examine: Whether the statement “Although stem cells are not differentiated, they are specialized and therefore give rise only to specific cell types” is correct or incorrect.

Introduction: Stem cells are undifferentiated cells. With specific growth factors they can give rise to different types of cells.