Cell Junctions and the Extracellular Matrix

In connective tissues such as bone or tendon, which component bears most of the mechanical stress to which the tissue is subjected?

Which type of junction connects the intermediate filaments in one cell to those in the next cell?

The adhesion of cadherin molecules is dependent on the presence of which ion in the extracellular medium?

What is the term for the type of binding where cadherin molecules of a specific subtype on one cell bind to cadherin molecules of the same or a closely related subtype on an adjacent cell?

Which intracellular adaptor protein complex links classical cadherins to the actin cytoskeleton at adherens junctions?

The human autoimmune disease pemphigus, which causes severe skin blistering, results from antibodies being made against which type of protein?

What are the two distinct functions of tight junctions in a transporting epithelium?

What is the approximate upper molecular mass limit for molecules that can pass through vertebrate gap junctions?

A gap-junction channel, or connexon, is constructed from how many transmembrane connexin subunits?

What is the name of the cylindrical structure, derived from the smooth endoplasmic reticulum, that runs through the center of most plasmodesmata in plant cells?

Selectins are cell-surface proteins that mediate transient cell-cell adhesions in the bloodstream by binding to what type of molecule on other cells?

Which of the following is NOT one of the three major classes of macromolecules that constitute the extracellular matrix?

What is the name of the simplest glycosaminoglycan (GAG), which consists of a single long chain of up to 25,000 disaccharide units and is not typically linked to a core protein?

What is the most abundant protein in mammals, constituting 25 percent of the total protein mass?

A deficiency in vitamin C (ascorbic acid) causes scurvy because the vitamin is a required cofactor for the enzyme that carries out which post-translational modification essential for stable collagen triple-helix formation?

Marfan syndrome, a genetic disorder affecting connective tissue, is caused by mutations in the gene for which protein that is essential for the integrity of elastic fibers?

The assembly of insoluble fibronectin fibrils on the cell surface is regulated by tension transmitted from the actin cytoskeleton via which family of transmembrane receptors?

What is the primary organizing protein of the basal lamina, which can self-assemble into a network and is composed of alpha, beta, and gamma chains?

Hemidesmosomes are cell-matrix junctions that anchor which type of cytoskeletal filaments to the basal lamina?

The genetic disease leukocyte adhesion deficiency (LAD), which leads to recurrent life-threatening infections, is caused by a failure to synthesize functional versions of which integrin subunit?

The activation of integrins from an inactive (folded) state to an active (extended) state involves a major conformational change that exposes binding sites for which two types of molecules?

In the cell walls of higher plants, what is the most abundant organic macromolecule on Earth that provides tensile strength?

What is the primary driving force for cell expansion in plants?

In a growing plant cell, what cellular structures are thought to orient the deposition of new cellulose microfibrils, thereby controlling the direction of cell elongation?

What is the name for the transmembrane enzyme complexes that spin out cellulose microfibrils from the plant cell surface?

In vertebrate epithelia, which junction forms a continuous adhesion belt, or zonula adherens, that encircles each of the cells in the sheet?

The immunoglobulin (Ig) superfamily of adhesion molecules, such as NCAM and ICAM, are distinct from cadherins and selectins in that their adhesive function is independent of what?

What is the typical repeating amino acid sequence in collagen alpha chains that allows them to form a tight triple-stranded helix?

The tripeptide sequence Arg-Gly-Asp (RGD) found in fibronectin is a primary binding site for which family of cell-surface receptors?

In the human genome, approximately how many members are there in the cadherin superfamily?

Which statement accurately describes the main structural difference between epithelial tissue and connective tissue?

What is the role of the protein vinculin at an adherens junction, as described in the text?

What is the primary function of proteoglycans and glycosaminoglycans (GAGs) in the extracellular matrix?

How do the tight junctions in the epithelium of the small intestine compare to those in the urinary bladder in terms of permeability to inorganic ions like Na+?

What are the large scaffold proteins, such as ZO-1, ZO-2, and ZO-3, responsible for at tight junctions?

Which statement accurately describes the function of Type VII collagen?

What is the primary role of the propeptides on fibrillar procollagen molecules?

How many exons, most of which are 54 or a multiple of 54 nucleotides long, are typically found in the genes that encode the alpha chains of fibrillar collagens?

In the process of germ-band extension in the Drosophila embryo, which of the following events occurs?

What type of intercellular junction in animal tissues is functionally most similar to plasmodesmata in plant tissues?

In most connective tissues, the extracellular matrix macromolecules are secreted by which type of cell?

What is the approximate diameter of a cellulose microfibril in a plant primary cell wall?

What is the role of focal adhesion kinase (FAK) in cell-matrix adhesions?

Which component of the cadherin superfamily is described as having more than 30 extracellular cadherin domains?

What type of cadherin is found on nerve, muscle, and lens cells?

What is the primary function of the initial 'rolling' adhesion of white blood cells on endothelial surfaces, mediated by selectins?

Which large proteoglycan, a major component of cartilage, has a mass of about 3 million daltons and assembles with hyaluronan to form huge aggregates?

In the basal lamina, what is the role of the glycoprotein nidogen?

How many distinct types of integrins are found in humans, formed from combinations of 18 alpha-chain and 8 beta-chain genes?

The inside-out activation of an integrin, such as in platelets responding to thrombin, is typically initiated by the binding of which intracellular protein to the integrin beta-chain tail?