Chapter 17 Homework

Which of the following is/are true of eicosanoids? Check all that apply.

They are formed from the conversion of arachidonic acid by enzymes called cyclooxygenase and acetylcholinesterase. They have 20-carbon backbones derived from a polyunsaturated fatty acid called arachidonic acid. They are formed from the conversion of arachidonic acid by enzymes called cyclooxygenase and lipoxygenase.

When cells cannot absorb glucose, they must get their energy someplace else, and, in turn, they metabolize fat and protein. In time, this leads to __________.

a condition called ketoacidosis, causing deep, gasping breathing

The second messenger cAMP is synthesized by the enzyme __________.

adenylyl cyclase

Some peptide hormones and other stimuli liberate ____________ from one of the phospholipids of the plasma membrane.

arachidonic acid

They have 20 ____________ backbones derived from a polyunsaturated ____________ called arachidonic acid.

carbon; fatty acid

In the case of ____________ , phospholipase removes the phosphate-containing group from the head of a membrane phospholipid, leaving DAG, which remains embedded in the plasma membrane.

diacylglycerol

The ____________ are an important family of ____________ secretions.

eicosanoids; paracrine

The following two ____________ , cyclooxygenase and ____________ , then convert it to various eicosanoids.

enzymes; lipoxygenase

Steroid hormones are water-soluble. Group

false

The second messenger, cAMP, is made from ADP.

false

The steroid hormone-receptor complex binds to __________.

hormone response elements in DNA

The rate of hormone removal is called the __________, and the length of time required to clear 50% of the hormone from the blood is the __________.

metabolic clearance rate; half-life

The enzyme alpha-kinase adds __________ to proteins.

phosphates

Steroid hormones bind to ____________ of the target cell.

protein receptors in the cytoplasm or nucleus

The mode of action of steroid hormones involves __________.

stimulation of mRNA transcription

Steroid hormones travel in the blood attached to protein carriers.

true

Stress is defined as any situation that upsets homeostasis and threatens one's physical or emotional well-being.

true

In addition to cAMP, diglyceride and inositol triphosphate are common second ____________ .

messengers

Choose the correct statement(s) on how cells regulate their sensitivity to circulating hormones. Check all that apply.

-Receptor-hormone interactions are similar to the enzyme-substrate interactions.-A receptor for one hormone will not bind other hormones.=When all the receptor molecules are occupied by hormone molecules, adding more hormone cannot produce any greater effect.

Physical causes of stress include __________. Check all that apply.

-malnutrition-intense exercise-infection

Inadequate hormone release is called hyposecretion. It can result from __________.

-tumors or lesions that destroy endocrine gland-tumors or lesions that interfere with its ability to receive signals from another gland-inadequate stiumulation of the gland

In both cases, a hormone binds to its receptor, activating a ____________ , which migrates to a phospholipase molecule and activates it.

G protein

The binding of epinephrine to its receptor activates a(n) __________.

G protein

The body's stress response or general adaptation syndrome (GAS) typically involves elevated levels of __________.

Glucocorticoids

In the case of ____________ , the phosphate-containing group removed is IP₃.

inositol triphosphate

Most hormones are taken up and degraded by the __________ and __________.

liver; kidney