CH 11 (Cell Communications)

One characteristic of life and living systems is that they are able to adapt. Toward this end, cells interact with other cells and their environment through the action of their _____.

One characteristic of life and living systems is that they are able to adapt. Toward this end, cells interact with other cells and their environment through the action of their _____.

plasma membrane and extracellular matrix

Osteocytes are bone cells. Collagen fibers and calcium salts are found in abundance between and among the osteocytes. The collagen and calcium salts are _____.

part of the extracellular matrix

What would you find in a plant cell

1) pectin

2) polysaccharides

3) lignin

A gap junction is a channel that connects adjacent cells. What cannot pass through a gap junction?

ribosomes

Plasmodesmata are cell-cell junctions that are found between _____.

adjacent plant cells

What is the function of the middle lamella in plant cells?

It allows adjacent cells to adhere to one another.

Put the steps of the process of signal transduction in the order they occur:
1. A conformational change in the signal-receptor complex activates an enzyme.
2. Protein kinases are activated.
3. A signal molecule binds to a receptor.
4. Target proteins are phosphorylated.
5. Second messenger molecules are released.

3, 1, 5, 2, 4

Protein kinase is an enzyme that _____.

activates or inactivates other proteins by adding a phosphate group to them

Not all intercellular signals require transduction. What signals would be processed
without transduction?

a lipid-soluble signal

Acetylcholine is a neurotransmitter that binds to receptors on skeletal muscle cells. The receptor-signal
complex brings about a series of events that result in contraction of skeletal muscle. Venom from black
widow spiders causes an explosive release of acetylcholine. What would that do to its victims?

The victim's muscles would be unable to relax.

Pemphigus vulgaris is an autoimmune disorder in humans in which antibodies are produced against the
cadherins of desmosomes. The blistering of the skin and mucous membranes characteristic of this disorder is
probably a result of _____.

a loss in cell-cell adhesion

Which of the following statements about quorum sensing is not accurate?

A) Quorum sensing may result in biofilm formation.
B) Quorum sensing is particularly well studied because of its importance in understanding interactions
between prokaryotes and eukaryotes.
C) Quorum sensing is species specific.
D) Quorum sensing is cell-cell communication in prokaryotes.

B