How do steroid hormones differ from polypeptide hormones and most amino-acid-derived hormones? a. Steroid hormones are lipid soluble and cross plasma membranes readily. b. Polypeptide and amino-acid-derived hormones are longer lived in the bloodstream and thus exert greater signal amplification. c. Polypeptide hormones are the most structurally complex and induce permanent changes in target cells. d. Only steroid hormones bind to receptors in the plasma membrane.

What is a hormone-response element? a. a receptor for a steroid hormone b. a receptor for a polypeptide hormone c. a segment of DNA where a hormone–receptor complex binds d. an enzyme that is activated in response to hormone binding and produces a second messenger

Which of the following assertions regarding hormones is correct? Select True or False for each statement. T/F Growth and metamorphosis are controlled by hormones. T/F Cortisol stimulates the production of ACTH. T/F Hormones produced by the hypothalamus are considered neurohormones. T/F Hormonal changes during puberty and pregnancy are forms of endocrine disruption.

True or False: In hormone systems, negative feedback occurs when the presence of a hormone inhibits release of the hormone.

Compare and contrast the modes of action of lipid-soluble and water-soluble hormones.

Why is the observation that one hormone may bind to more than one type of receptor important?

Compare and contrast the structure and function of the anterior and posterior pituitary glands.

Design a study to test the hypothesis that the symptoms of jet lag are caused by disruption of normal daily cortisol rhythms.

Suppose that during a detailed anatomical study of a marine invertebrate, you found a small, previously undescribed structure. How would you test the hypothesis that the structure is a gland that releases one or more hormones?

Scientists set out to test the hypothesis that the herbicide atrazine is an endocrine disruptor that feminizes male amphibians. They treated male amphibians with atrazine and then compared their circulating testosterone concentration with those of males and females that were not treated with atrazine (controls). The results are shown here (* signifies P<0.05). Was the hypothesis supported? Why or why not?

Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world's largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins' ability to respond to stressors? Has it affected the penguins' secretion of corticosterone? Corticosterone is a(n): a. neurohormone b. steroid hormone c. amino-acid-derived hormone d. polypeptide hormone

Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world's largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins' ability to respond to stressors? Has it affected the penguins' secretion of corticosterone? In what part(s) of a target cell would you expect to find corticosterone receptors?

Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world's largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins' ability to respond to stressors? Has it affected the penguins' secretion of corticosterone? If penguins in a colony are habituated to the presence of tourists, how would their corticosterone response to being visited by tourists compare to that of penguins in a colony not previously exposed to tourists?

Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world's largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins' ability to respond to stressors? Has it affected the penguins' secretion of corticosterone? Scientists tested the hypothesis that penguins habituated to tourists have a blunted stress response overall. They examined the corticosterone response of habituated and non-habituated penguins to another stressor—that of being captured and restrained for 30 minutes. They found that both habituated and non-habituated penguins secreted corticosterone in response to being captured and restrained, but that the level of corticosterone after 30 minutes differed between the groups. The results are shown here (* means P<0.05). Was the hypothesis supported? Explain.

Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world's largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins' ability to respond to stressors? Has it affected the penguins' secretion of corticosterone? In response to a visit by tourists, which penguins—habituated or non-habituated—would show a greater change in expression of genes for liver enzymes involved in converting amino acids to glucose? Explain.

Ecotourism helps conserve wildlife by increasing the value of wildlife conservation for local people. In Argentina, the world's largest breeding colony of Magellanic penguins is visited by thousands of tourists every year, causing the penguins to become habituated to the presence of people. Has ecotourism affected the penguins' ability to respond to stressors? Has it affected the penguins' secretion of corticosterone? Suggest at least two distinct physiological mechanisms that could be responsible for the difference in corticosterone response to a stressor in habituated and non-habituated penguins.