Exam 16: Cell Walls, the Extracellular Matrix, and Cell Interactions

The X-linked variant of Charcot-Marie-Tooth disease is likely caused by mutations in a gene encoding a probable connexin 32. Suppose your laboratory is working with a human cell line called HeLa cells, which do not express connexins. Propose an experiment to demonstrate that the probable wild-type connexin 32 is actually a gap junction protein.

How is proline hydroxylation in collagen encoded in the genome? What is the relationship between this encoding mechanism and scurvy?

How many molecules of the gap junction protein form one open channel between two cells?

What prevents collagen from assembling into fibrils inside the cell?

The major cell surface receptor(s) responsible for the attachment of cells to the extracellular matrix is(are)

The structural polysaccharide of fungal cell walls is the same as the one found in insect

In plant cell walls, _______ are highly branched polysaccharides that are hydrogen-bonded to cellulose microfibrils.

What are the four classes of cell adhesion molecules?

The individual units of gap junctions are composed of _______ molecules.

Vitamin C deficiency may lead to scurvy, a disease characterized by skin lesions and blood vessel hemorrhages due to weakened connective tissue. Vitamin C deficiency has this effect because the vitamin is

The amino acid sequence of a collagen triple helix domain consists of Gly-X-Y repeats, in which X is frequently _______ and Y is frequently _______.

Within the plant cell wall, cellulose microfibrils are embedded in a matrix consisting of proteins and two other types of polysaccharides: _______ and _______.

Describe the structure of laminins.

Pectins form a _______ network in plant cell walls.

Basal laminae are formed primarily from type IV collagen and other proteins.

The thin, sheetlike basal laminae are found

Describe the structure of an integrin, as determined from the cDNA sequence isolated from fibroblasts by Hynes et al.

If developing pre-nerve cells expressing only N-cadherin on their surfaces were mixed with epithelial cells expressing only E-cadherin, what would be the most likely result?

Why is the term "basal lamina" preferred over the term "basement membrane"?

Gap junctions allow passage of molecules that have a molecular weight of less than _______ daltons.