Which of the following animals uses the largest percentage of its energy budget for homeostatic regulation?
a. Marine jelly (an invertebrate)
b. Snake in a temperate forest
c. Desert insect
d. Desert bird

Negative-feedback mechanisms are

a. Most often involved in maintaining homeostasis.

b. Analogous to a furnace that produces heat.

c. Found only in birds and mammals.

d. All of the above.

An animal's inputs of energy and materials would exceed its outputs

a. If the animal is an endotherm, which must always take in more energy because of its high metabolic rate

b. If it is actively foraging for food

c. If it is growing and increasing its mass

d. Never; due to homeostasis, these energy and material budgets always balance

Which of the following cell structures would you expect to be most important in the growth of bacteria on the surface of your teeth?

a. Cell wall

b. Fimbriae

c. Flagella

d. Cilia

Which of the following best illustrates homeostasis? (Explain your answer.)

a. Most adult humans are between 5 and 6 feet tall.

b. All the cells of the body are about the same size.

c. When the salt concentration of the blood goes up, the kidneys expel more salt.

d. When oxygen in the blood decreases, you feel dizzy.

Draw a model of the control circuit(s) required for driving an automobile at a fairly constant speed over a hilly road. Indicate each feature that represents a sensor, stimulus, or response.

The eukaryotic cytoskeleton is a highly dynamic network of filaments and motor proteins. Which of the following correctly describe activities of these cytoskeletal components? Select True or False for each statement.

T/FMyosin motors walk toward the plus ends of intermediate filaments.

T/FDynein motors are responsible for the whip-like movement of eukaryotic flagella.

T/FKinesin motors move vesicles along tracks toward the microtubule-organizing center.

T/FActin filaments are required for cytoplasmic streaming.

Suppose a cell is placed in a solution with a high concentration of potassium and no sodium. How would the cellular sodium–potassium pump function in this environment?

a. It would stop moving ions across the membrane.

b. It would continue using ATP to pump sodium out of the cell and potassium into the cell.

c. It would move sodium and potassium ions across the membrane, but no ATP would be used.

d. It would reverse the direction of sodium and potassium ions to move them against their gradients.