Ch 9. Cell Communication

The system of communication between cells through signaling pathways is called homeostasis.

	a.	True
	b.	False

False

In the liver, the enzyme glycogen phosphorylase catalyzes the breakdown of glucose.

	a.	True
	b.	False

False

Steroid hormones, such as testosterone and estrogen, are polar signaling molecules

	a.	True
	b.	False

False

After the binding of a signaling molecule to a surface receptor, the signaling molecule does not enter the cell.

	a.	True
	b.	False

True

After signal transduction has run its course, receptor molecules are removed from the surface by endocytosis; one possible fate of the receptor is to be separated from its signaling molecule and returned to the cell surface.​

	a.	True
	b.	False

True

G-protein-coupled receptors are found in both prokaryotes and eukaryotes.

	a.	True
	b.	False

False

In plants, the IP₃/DAG pathways control the organism's responses to water loss and changes in light intensity.

	a.	True
	b.	False

True

Steroid hormones are nonpolar molecules derived from cholesterol.​

	a.	True
	b.	False

a.

True

In breast cancer, ERα is often lost, which increases cell proliferation.

	a.	True
	b.	False

False

Cross-talk between second messenger pathways is probably involved in particular types of olfactory signal transduction in many animals.​

	a.	True
	b.	False

a.

True

In order for a target cell to receive a signal, it must possess a ____ specific to the signaling molecule.​

	a.	​glycolipid
	b.	​glycoprotein
	c.	​receptor
	d.	​transfer protein
	e.	​hormone

c.

​receptor

Adjacent animal cells utilize ____ to rapidly communicate with each other.​

	a.	​gap junctions
	b.	​plasmodesmata
	c.	​hormones
	d.	​desmosomes
	e.	​neurotransmitters

a.

​gap junctions

Adjacent plant cells utilize ____ to rapidly communicate with each other.​

	a.	​gap junctions
	b.	​plasmodesmata
	c.	​transport proteins
	d.	​desmosomes
	e.	​neurotransmitters

b.

​plasmodesmata

How do cells in the body of a multicellular organism communicate with each other?​

	a.	​by way of signaling molecules that interact with specific receptors
	b.	​through long projections that directly connect cells to each other
	c.	​through electrical signals passed between a cell and its external environment
	d.	​by the transport of ions between cells in different parts of the organism
	e.	​by the transport of ions in water

a.

​by way of signaling molecules that interact with specific receptors

Substance B is synthesized in neurons, travels through gap junctions, and triggers the transduction of an electrochemical signal. This is an example of ____.​

	a.	​autocrine signaling
	b.	​paracrine signaling
	c.	​long-distance signaling
	d.	​local signaling
	e.	​communication by direct contact

e.

​communication by direct contact

Substance A is synthesized in the liver, travels through the circulatory system bound to a carrier protein, and causes a change in gene expression in a target cell. This is an example of ____.​

	a.	​autocrine signaling
	b.	​paracrine signaling
	c.	​long-distance signaling
	d.	​local signaling
	e.	​communication by direct contact

c.

​long-distance signaling

In order for a cell to respond to the signaling molecule epinephrine, it must have ____.​

	a.	​ion channels
	b.	​a lipid bilayer through which epinephrine can pass
	c.	​receptors with an epinephrine binding site on the cytoplasmic side of the  plasma membrane
	d.	​receptors with an epinephrine binding site on the plasma membrane surface
	e.	​nuclear membrane receptors

d.

​receptors with an epinephrine binding site on the plasma membrane surface