Exam 5: Control of Cells by Chemical Messengers

Aspirin and other nonsteroidal anti-inflammatory drugs are more specific in their effects on eicosanoid synthesis than are steroidal anti-inflammatory drugs.

Which of the following are known to be second messengers?

Activated calmodulin functions to activate or inactivate cytosolic enzymes.

Which of the following are common means by which binding of an intercellular chemical messenger with a cell's receptor brings about an intracellular response?

An antagonist blocks the action of a chemical messenger by binding to its receptor.

Another term for lipid soluble hormones is

Amplification of a second messenger cascade can take place at this level:

The significance of plasma membrane receptors for chemical regulators such as hormones and neurotransmitters is that

Activation of a receptor that is coupled by G proteins to adenylyl cyclase

At very low concentrations,epinephrine causes an artery to vasodilate.At higher concentrations epinephrine causes the same artery to constrict.How can these different effects be explained?

The enzyme that catalyzes the production of cAMP from ATP is phosphodiesterase.

Activation of a receptor by a chemical messenger

First messengers may bind to a membrane receptor that then transforms to an ionic diffusion channel which promotes a change in membrane polarity.

Messages,in the form of chemical signals,are sent from one cell to another with only those capable of receiving the specific chemical able to respond to them.Water soluble signals have receptors

Which of the following statements about G proteins is not correct? G proteins may

Cyclic AMP activates allosteric proteins.

Amplification during a second messenger cascade is beneficial because amplification

Phosphorylation is a necessary component of any enzyme activation.

Competition for receptors is strictly a pharmacological phenomenon,since naturally occurring chemical messengers do not compete with each other for the same receptor site.

Lipid soluble hormones which pass through the membrane bind with receptors at the nucleus and then increase the rate of mRNA synthesis to