AP Bio Homeostasis

The following chart is a comparison of the metabolic response to temperature of an endotherm (15-20 pound bird) and of an ectotherm (15-20 pound lizard).

Which of the following is a plausible explanation about metabolic rate for the responses indicated on the graph?

• The metabolic rate of endotherms varies directly with the environment.

• The metabolic rate of ectotherms remains constant at all temperatures.

• The metabolic rate of ectotherms increases at higher temperatures.

• The metabolic rate of endotherms and ectotherms do not very with the temperature changes.

Which of the following may explain how endotherms deal with temperature changes?

• The energy cost of heat production is lower at lower termperatures.

• Active cooling mechanisms require energy and are present at high ambient tempertures.

• Endotherms use passive cooling mechanisms at moderate temperatures.

• The temperature of tissues decreases as a result of Q₁₀ effects at high temperatures.

Which of the following physiological responses will occur immediately after your afternoon meal of chicken nuggets, French fries, and a small milkshake at McDonalds?

• You body will secret glucagon to convert glycogen into glucose.

• You will metabolize the fat from the French fries immediately.

• Your body will secrete insulin in response to the high carbohydrate meal.

• Your blood glucose levels will decrease due to the protein content of the chicken.

In most freshwater fish, nitrogenous waste is primarily excreted as ammonia, which is highly soluble in water and is toxic at low concentrations. In terrestrial mammals, ammonia is converted to urea before it is excreted. Urea is

also highly soluble in water but is less toxic than ammonia at low concentrations. Which of the following best explains why freshwater fish do not convert ammonia to urea for excretion?

• The metabolic pathways of fish do not normally involve nitrogen consumption.

• The dilution of ammonia by direct excretion into freshwater conserves energy.

• Ammonia is concentrated in tissues, where it is stored prior to excretion.

• The nitrogen in ammonia is recycled for use in protein and nucleotide synthesis.

Ethylene is an organic compound produced by ripening fruits. In a controlled experiment, researchers found that ethylene gas stimulated the ripening process in newly harvested fruits. Which of the following describes the most likely connection between natural ethylene production

and fruit ripening?

• As a result of metabolic inactivity, newly harvested fruits are unable to absorb ethylene gas from the atmosphere.

• Ethylene gas is a chemical signal through which ripening fruits trigger the ripening process in other fruits.

• Because of normal phenotypic variation, only some of the fruits in a given generation are expected to produce ethylene gas.

• The rate of ethylene gas production by ripening fruits is an indicator of the relative age of an ecosystem.