The body’s adaptive immune response differs from its innate immune response in that the adaptive response (select all that apply):
a. targets specific pathogens.
b. is faster to ramp up.
c. has no memory of the pathogens it has faced.
d. works primarily through T and B cells.
e. is more powerful than the innate response.
Antibodies are seen in two forms in immune system functioning, as ______ and as ______.
a. a length of DNA in a macrophage; a hormone
b. an antigen receptor on a T cell; a free-standing protein exported by a T cell
c. an antigen receptor on a B cell; a free standing protein exported by a B cell
d. antigen receptors on macrophages; signaling proteins inside macrophages
e. proteins that can kill invaders directly; signaling proteins
Pancreatic beta cells can sense high levels of circulating glucose and, in response, secrete insulin, which helps move glucose out of circulation. These cells can likewise sense the resulting low circulating glucose levels, and when they do, they reduce their secretion of insulin. This is negative feedback in action; the product of beta cell activity (insulin) ultimately has the effect of reducing beta cell activity. Why does the body constantly utilize negative feedback to maintain the stable state called homeostasis? Why couldn’t it use positive feedback instead?
Steroid hormones are all _____ and generally bind to receptors____.
a. produced in greater amounts by males; on muscle cells
b. built around the framework of the cholesterol molecule; on fat cells
c. composed of chains of amino acids; on a target cell’s outer or plasma membrane
d. built around the framework of the cholesterol molecule; inside target cells
e. muscle-building hormones; on muscle cells