Deck 15: Energy Balance and Thermal Physiology

Question 1

Which of the following statements about energy is NOT correct?

A) Energy is subject to an input-output balance similar to that for water.
B) An example of internal work is the energy expended by muscles to lift a heavy object.
C) Almost 75% of nutrient energy is lost as heat and not used to do work.
D) Energy is normally expressed in terms of heat energy.
E) none of these.

Answer 1

An example of internal work is the energy expended by muscles to lift a heavy object.

Question 2

Which of the following is not correctly paired?

A) chemical energy in ATP and kinetic energy of locomotion
B) standard metabolic rate and resting metabolic rate
C) basal metabolic rate and thermal neutral zone
D) field metabolic rate and average metabolic expenditure over time
E) endotherms and amphibians

Answer 2

endotherms and amphibians

Question 3

Metabolic scope measurements

A) are measured during periods of aerobic activity.
B) involve the use of treadmills.
C) are an indicator of an animal's activity capacity.
D) are the ratio of metabolic rate to SMR.
E) two of these.

Answer 3

two of these.

Question 4

Obligatory diet-induced thermogenesis activity

A) results from an increase in metabolic activity associated with processes occurring in the gut.
B) is the increase in heat production that occurs after a meal
C) has historically been studied in endotherms.
D) is affected by the amount of food an animal consumes.
E) all of these.

Question 5

Diet-induced thermogenesis

A) is the generation of heat to compensate for sudden weight loss associated with dieting.
B) is an increase in metabolic rate due to the energy expenditures associated with feeding and digestion.
C) is the generation of heat associated with "fat-burning" diets.
D) offsets the energy expenditures associated with SMR and BMR.
E) involves both internal and external work.

Question 6

The fact that large animals typically have lower basal metabolic rates than smaller animals can be explained by

A) their larger size which means they have more surface area for absorbing radiant energy, so they require less metabolic energy to stay warm.
B) their larger size which makes them less susceptible to predation, so they don't have to use energy to escape from predators.
C) their greater weight which makes them less inclined to move, so they expend less energy in locomotion.
D) their lower surface to volume ratio which means they lose a lesser percentage of their energy to the environment.
E) none of these.

Question 7

The "animal energy equation" for endotherms states that E_input-E_loss= E_BMR+E_production+E_activity+E_DIT.
In this equation, E_loss refers to

A) thermal energy given off as a consequence of the first law of thermodynamics.
B) thermal energy given off as a consequence of the second law of thermodynamics.
C) thermal energy given off as a consequence of dietary intake.
D) potential energy given off in the form of undigested foodstuffs (feces), sloughed skin, hair or other body products.
E) none of these.

Question 8

If a reduction of body mass is one's goal, then the factor in the animal energy equation one would most like to ________ is ________.

A) decrease; E_BMR
B) decrease; E_loss
C) decrease; E_production
D) increase; E_production
E) increase; E_input

Question 9

Uncoupling proteins function in maintaining long-term neutral energy balance by

A) uncoupling electron transport in mitochondria from ATP production.
B) uncoupling glycolysis from ATP production.
C) uncoupling food intake from nutrient uptake in the gut.
D) all of these.
E) none of these.

Question 10

BMR

A) is regulated by thyroid hormones.
B) is affected by bile acids.
C) is affected by the amount of fat in the diet.
D) all of these.

Question 11

Which of the following has the highest rate of energy expenditure?

A) sexual intercourse
B) bicycling on a level surface
C) swimming
D) jogging
E) walking up stairs

Question 12

Ghrelin and obestatin

A) are secreted by the digestive tract.
B) arise from the same gene.
C) arise from the same protein.
D) are secreted by the digestive tract and arise from the same gene.
E) all of these.

Question 13

Which of the following does not function in decreasing appetite?

A) cholecystokinin (CCK)
B) ghrelin
C) corticotropin releasing hormone
D) PYY_3-36
E) insulin

Question 14

Leptin stimulates the hypothalamus to secrete ________, which in turn acts to _____ appetite.

A) $\alpha$ -MSH; stimulate
B) $\alpha$ -MSH; suppress
C) melanocortin; stimulate
D) melanocortin; suppress
E) none of these.

Question 15

Which of the following animals would you expect to have the most unsaturated fatty acyl chains in the plasma membranes of its cells?

A) arctic fish
B) penguins
C) polar bears
D) tropical fish
E) pelicans

Question 16

Skeletal muscle myosin from lizard shows maximal ATPase activity over a wide range of temperatures. This is due to the fact that

A) in poikilothermic organisms, muscles must function over a broad range of temperatures, and myosin ATPase activity is essential for muscle function.
B) at lower temperatures, myosin can uncouple from actin, and the ATPase activity can be used to generate heat without locomotion, allowing the lizard to warm up metabolically.
C) both of these.
D) neither of these.

Question 17

Metabolic thermoregulators are considered ____ since they rely on (bio)chemical reactions to maintain their body temperature when they are losing heat to the environment.

A) ectothermic
B) endergonic
C) poikilothermic
D) endothermic
E) homeothermic

Question 18

When elephants get hot, they flap their ears. This works nicely as a mechanism for heat loss because

A) the large surface to volume ratio of the ear favors loss of heat to the environment.
B) the flapping favors heat loss by conduction.
C) the flapping favors heat loss by convection.
D) the flapping favors heat loss by evaporation.
E) all of these.

Question 19

While working outside on a hot day the wind blows making you feel cooler. This is most likely due to heat loss through

A) conduction.
B) convection.
C) evaporation.
D) radiation.
E) metabolism.

Question 20

Some ecotherms survive freezing despite the fact that as much as _______ of their body water freezes.

A) 25%
B) 45%
C) 50%
D) 65%
E) 80%

Question 21

Which of the following statements is NOT true?

A) Some ectotherms can regulate their body temperature as efficiently as a mammal.
B) Ectothermic regulators may also be poikilotherms.
C) Endotherms gain all their heat from internal, biochemical reactions.
D) Some poikilotherms are homeotherms.
E) None of these.

Question 22

Peeper frogs freeze during the winter. As they begin to freeze, their livers break down glycogen and release glucose into the blood, which can then be taken up into cells. This provides a benefit to the frog in that

A) plasma glucose acts as a cryoprotectant by lowering the freezing point of the extracellular fluid.
B) cellular glucose acts as a cryoprotectant by lowering the freezing point of the intracellular fluid.
C) cellular glucose is readily available for glycolysis once the frog thaws.
D) all of these.
E) none of these.

Question 23

Animals that practice freeze avoidance have antifreeze proteins which

A) lower the freezing point of plasma due to their colligative properties.
B) raise the melting point of plasma ice due to their colligative properties.
C) nucleate the formation of ice crystals in the extracellular fluid.
D) interact with ice crystals to prevent their growth.
E) none of these.

Question 24

Heat shock proteins

A) are also known as stress proteins.
B) are hydrophobic proteins.
C) are attracted to hydrophobic amino acids normally located on the inside of folded proteins.
D) are also called molecular chaperones.
E) all of these.

Question 25

Polar bears have black skin. This characteristic helps them deal with cold stress by

A) increasing the amount of air trapped next to the skin.
B) increasing the absorption of radiant energy from the sun.
C) increasing the insulation provided by subcutaneous fat.
D) reducing heat loss by restricting blood flow to the skin.

Question 26

Vasoconstriction helps an animal retain heat by

A) generating heat through the metabolic activity of the vascular musculature.
B) causing piloerection, which increases the amount of air (a poor thermal conductor) trapped next to the skin.
C) directing blood away from the body surface, avoiding the transfer of heat from the blood to the environment.
D) causing the skin of the animal to blanch, increasing the ability of radiant energy to penetrate to the animal's core.
E) none of these.

Question 27

The advantage of shivering over other forms of muscle activity (like running) as a means of thermogenesis is

A) shivering increases ATP use and heat production without increasing heat loss due to convection.
B) with shivering all the energy expended is released as heat since no work is done.
C) shivering increases ATP use and heat production without increasing heat loss due to conduction.
D) shivering increases ATP use and heat production without increasing heat loss by either convection or conduction.
E) all of these.

Question 28

Small desert mammals are often osmotically stressed in addition to being heat stressed; therefore they will want to

A) avoid heat loss by evaporative cooling and instead employ heat storage mechanisms to deal with heat stress.
B) avoid heat loss by evaporative cooling and instead burrow to seek cooler microclimates.
C) avoid heat loss by evaporative cooling and instead restrict their activity to night when ambient temperatures are cooler.
D) avoid heat loss by entering into extended periods of sleep and inactivity during the summer (estivation) which is similar to hibernation by some animals in the winter.
E) avoid heat loss by evaporative cooling by burrowing and restricting activity to times with cooler temperatures.

Question 29

When a bird ruffles its feathers in response to heat stress it

A) permits convective currents to carry heat away from the body surface.
B) permits exchange of air with 100% humidity for air with lower humidity, enabling evaporative cooling to occur.
C) both of these.
D) neither of these.

Question 30

The thermal neutral zone (TNZ) is

A) range of environmental temperatures when the animal does not need to expend large amounts of energy on thermoregulation.
B) the body temperatures which an animal maintains while at its basal metabolic rate.
C) the range in environmental temperatures where mechanisms involving insulation are sufficient.
D) two of these.
E) all of these.

Question 31

In birds, the hypothalamus does not

A) stimulate shivering.
B) stimulate panting.
C) stimulate erection of plumage.
D) none of these.

Question 32

The ambient temperature at which metabolism increases to cope with heat loss to the environment is called the

A) lower critical temperature.
B) critical neutral temperature.
C) upper critical temperature.

Question 33

Fever

A) is a hypothalamic response to pyrogens released by white blood cells.
B) is a pathological response to combat infections.
C) is a poorly understood mechanism to fight disease.
D) two of these.
E) all of these.

Question 34

Regional heterotherms are animals that are

A) ectotherms in certain parts of their range and endotherms in other parts of their range.
B) endotherms that only practice thermogenesis in certain strata of their habitat.
C) endothermic, but only in specific tissues of their body.
D) two of these.
E) all of these.

Question 35

For reasons that are uncertain, hibernating animals periodically rewarm and recool during the hibernation period. It is thought that this is because

A) they need to void wastes.
B) they need to eat a little to restore glycogen stores, especially in their brains.
C) they need to rewarm to activate their immune systems in case they've become infected.
D) two of these.
E) all of these.

Question 36

Minimal metabolic rate is measured

A) at the optimal temperature for the organism.
B) during sleep.
C) with diet-induced thermogenesis subtracted from the final value.
D) two of these.
E) all of these.

Question 37

For running mammals

A) the increase in metabolism is roughly linear with velocity.
B) the increase in metabolism is inversely related to velocity.
C) the increase in metabolic rate is independent of velocity.

Question 38

Naked mole rats are unusual mammals that

A) have no hair.
B) produce young parthenogenically.
C) don't nurse their young.
D) are ectothermic.
E) don't regulate body mass.

Question 39

According to the second law of thermodynamics, as life become more organized the
environment becomes disorganized.

Question 40

BMR and SMR are constant for a species.

Question 41

Leptin signaling is the dominant factor responsible for long-term balance of total body
energy.

Question 42

Cryoprotective dehydration allows cells to freeze without ice crystal buildup inside the
cells.

Question 43

Adipocytes secrete messengers called adipokines one of which is adiponectin.

Question 44

The joule is the international unit for one calorie.

Question 45

Respirometry can be used to measure minimal metabolic rate.

Question 46

The membranes of a warm-adapted organism generally contain saturated fatty acids.

Question 47

Poikilothermic ectotherms that live in thermally variable environments manage to
maintain a relatively stable body temperature.

Question 48

One of the ways that birds retain internal heat involves behavioral insulation.

Question 49

Match each sentence with the most appropriate choice:

-Leptin

A) hibernation
B) stomach
C) feathers
D) dark surface
E) variable body temperature
F) constant body temperature
G) high thermal conductivity
H) low thermal conductivity
I) heat exchange
J) endothermic animals

Question 50

Match each sentence with the most appropriate choice:

-Ghrelin

A) hibernation
B) stomach
C) feathers
D) dark surface
E) variable body temperature
F) constant body temperature
G) high thermal conductivity
H) low thermal conductivity
I) heat exchange
J) endothermic animals

Question 51

Match each sentence with the most appropriate choice:

-Heat retention

A) hibernation
B) stomach
C) feathers
D) dark surface
E) variable body temperature
F) constant body temperature
G) high thermal conductivity
H) low thermal conductivity
I) heat exchange
J) endothermic animals

Question 52

Match each sentence with the most appropriate choice:

-Heat acquisition

A) hibernation
B) stomach
C) feathers
D) dark surface
E) variable body temperature
F) constant body temperature
G) high thermal conductivity
H) low thermal conductivity
I) heat exchange
J) endothermic animals

Question 53

Match each sentence with the most appropriate choice:

-Poikilotherm

A) hibernation
B) stomach
C) feathers
D) dark surface
E) variable body temperature
F) constant body temperature
G) high thermal conductivity
H) low thermal conductivity
I) heat exchange
J) endothermic animals

Question 54

Match each sentence with the most appropriate choice:

-Homeotherm

A) hibernation
B) stomach
C) feathers
D) dark surface
E) variable body temperature
F) constant body temperature
G) high thermal conductivity
H) low thermal conductivity
I) heat exchange
J) endothermic animals

Question 55

Match each sentence with the most appropriate choice:

-Water

A) hibernation
B) stomach
C) feathers
D) dark surface
E) variable body temperature
F) constant body temperature
G) high thermal conductivity
H) low thermal conductivity
I) heat exchange
J) endothermic animals

Question 56

Match each sentence with the most appropriate choice:

-Air

A) hibernation
B) stomach
C) feathers
D) dark surface
E) variable body temperature
F) constant body temperature
G) high thermal conductivity
H) low thermal conductivity
I) heat exchange
J) endothermic animals

Question 57

Match each sentence with the most appropriate choice:

-Rete mirabile

A) hibernation
B) stomach
C) feathers
D) dark surface
E) variable body temperature
F) constant body temperature
G) high thermal conductivity
H) low thermal conductivity
I) heat exchange
J) endothermic animals

Question 58

Match each sentence with the most appropriate choice:

-Regional heterothermy

A) hibernation
B) stomach
C) feathers
D) dark surface
E) variable body temperature
F) constant body temperature
G) high thermal conductivity
H) low thermal conductivity
I) heat exchange
J) endothermic animals

Question 59

Based on your knowledge of the chemical structure of carbohydrates and fats, explain why the respiratory quotient (ratio of the volume of CO₂ produced per volume O₂ consumed) is higher for the former than the latter.

Question 60

Citing examples of each, compare and contrast torpor with hibernation.

Question 61

Many biological processes, e.g. enzyme-catalyzed reactions, have a temperature optimum. Explain why activity increases as temperature rises, reaches a maximum, and then decreases. What is the evolutionary/adaptational significance of the temperature optimum?

Question 62

Discuss the role of the hypothalamus and arcuate nucleus in food intake in mammals.

Question 63

Explain how countercurrent heat exchange is used in maintaining core bod temperature.

Question 64

There are times during thermoregulation when animals need to generate. Compare an contrast shivering and other muscle activity with nonshivering (chemical) thermogenesis as a means of generating body heat.