What is a fiber composite? How do cellular fiber composites resemble reinforced concrete?

Where are protein components of the extracellular matrix synthesized?

a. In the rough ER

b. In the Golgi apparatus

c. In the plasma membrane

d. In the extracellular layer itself

Which of the following actions correctly describe a role performed by at least one type of intercellular connection? Select True or False for each statement.

T/F Allows communication between adjacent cells.

T/F Forms a watertight barrier between the cells.

T/F Uses components of the extracellular matrix to indirectly connect adjacent cells.

T/F Associates with cytoskeletal components to resist pulling forces.

What does it mean to say that a signal is transduced?

a. The signaling molecule enters the cell directly and elicits a cellular response.

b. The signal is generated by the production of proteins.

c. The physical form of the signal changes between the outside of the cell and the inside.

d. The signal is amplified.

How do the extracellular filaments in plants differ from those in animals?

a. Plant filaments resist compression forces; animal filaments resist pulling forces.

b. Animal filaments consist of proteins; plant filaments consist of polysaccharides.

c. Plant extracellular filaments never move; animal filaments can slide past one another.

d. Plant filaments run parallel to one another; animal filaments crisscross.

Summarize the experimental evidence in sponges showing that animal cells adhere to each other selectively. Explain the molecular basis of selective adhesion.

Suppose you were to model amplification by the phosphorylation cascade in Figure 11.16, using a penny for each kinase 1, a nickel for each kinase 2, and a dime for each kinase 3. Also suppose that Ras and each of the kinases can activate 10 proteins. How much money would you need to construct your model?

What is the significance of the observation that many signal transduction pathways create a network, where they intersect or overlap?

Steroid hormones, like most lipid-soluble signaling molecules, are processed directly. How does the absence of a signal transduction cascade in the processing of steroid hormones affect (a) signal amplification?

Steroid hormones, like most lipid-soluble signaling molecules, are processed directly. How does the absence of a signal transduction cascade in the processing of steroid hormones affect (b) signal regulation?

Steroid hormones, like most lipid-soluble signaling molecules, are processed directly. How does the absence of a signal transduction cascade in the processing of steroid hormones affect (c) the cellular response that is possible?

Suppose you have an antibody that binds to the receptor tyrosine kinase illustrated in Figure 11.16. When you add this antibody to the cell, you find that it activates the cell response, even when no signaling molecule is present. Explain this result.