AP Bio: Chapter 32

Which of the following statements describes a negative feedback response? 1. The onset of contractions during childbirth stimulates the release of a hormone that stimulates further contractions. 2. A person who loses 3 pounds continues to diet to lose an additional 10 pounds. 3. The arrival of platelets at a wound site stimulates the recruitment of more platelets to form a clot. 4. After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels.

After a meal, blood sugar levels in the body rise; insulin is secreted to lower blood sugar levels.

Which of these is an example of negative feedback? 1. As a blood clot begins to form, the process of its formation gets faster and faster. 2. After you eat, glucagon stimulates an increase in blood sugar levels. 3. After you eat, insulin stimulates the lowering of blood sugar levels. 4. The digestive enzyme pepsinogen is converted to pepsin by the action of hydrochloric acid; pepsin itself can then convert pepsinogen into pepsin. 5. Once labor begins, contractions increase in frequency and intensity.

After you eat, insulin stimulates the lowering of blood sugar levels.

Which of the following is an accurate statement about thermoregulation? 1. Endothermy has a lower energy cost than ectothermy. 2. Endotherms are regulators and ectotherms are conformers. 3. Endotherms and ectotherms differ in their primary source of heat for thermoregulation. 4. Endotherms maintain a constant body temperature and ectotherms do not. 5. Endotherms are warm-blooded and ectotherms are cold-blooded.

Endotherms and ectotherms differ in their primary source of heat for thermoregulation.

Which component of a homeostatic system compares sensory information to a target value? Integrator. Sensor. Set point. Effector.

Integrator.

Which term describes a mechanism by which the internal conditions of an organism are kept at set values without regard to the external conditions? Negative feedback. Conformational homeostasis. Regulatory homeostasis. Thermoregulation.

Regulatory homeostasis

Which component of a homeostatic system perceives changes in some parameter of the environment? Set point. Sensor. Integrator. Effector.

Sensor

Which of the following actions acts to warm a homeothermic body? Shivering. Dilating blood vessels. Panting. Sweating.

Shivering.

African lungfish, which are often found in small stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation? 1. Urea forms an insoluble precipitate. 2. Small stagnant pools do not provide enough water to dilute the toxic ammonia. 3. Urea takes less energy to synthesize than ammonia. 4. The highly toxic urea makes the pool uninhabitable to potential competitors. 5. Urea makes lungfish tissue hypoosmotic to the pool.

Small stagnant pools do not provide enough water to dilute the toxic ammonia.

True or false? Organisms must maintain homeostasis because optimal enzyme activity is achieved within a very narrow range of conditions. True False

True

In a physiological system operating with positive feedback, _____. 1. only an effector/response and control center are necessary to complete the control system 2. a stimulus will initiate a response that returns the system to near its initial parameters 3. a change in a variable will amplify rather than reverse the change 4. a stimulus will prevent a small change from becoming too large 5. the range of acceptable values for a given parameter will be narrower than if the system were regulated by negative feedback

a change in a variable will amplify rather than reverse the change

During mammalian labor and delivery, the contraction of uterine muscles is enhanced by oxytocin. This is an example of 1. a hormone that is involved in a positive feedback loop. 2. signal transduction immediately changing gene expression in its target cells. 3. the key role of the anterior pituitary gland in regulating uterine contraction. 4. a hormone that acts in an antagonistic way with another hormone. 5. a negative feedback system.

a hormone that is involved in a positive feedback loop.

Natural selection should favor the highest proportion of juxtamedullary nephrons in which of the following species? a mouse species living in a temperate broadleaf forest a mouse species living in a desert a mouse species living in a tropical rain forest a river otter a beaver

a mouse species living in a desert

Different body cells can respond differently to the same peptide hormones because 1. the hormone is chemically altered in different ways as it travels through the circulatory system. 2. the circulatory system regulates responses to hormones by routing the hormones to specific targets. 3. each cell converts that hormone to a different metabolite. 4. different target cells have different sets of genes. 5. a target cell's response is determined by the components of its signal transduction pathways.

a target cell's response is determined by the components of its signal transduction pathways.

An example of effectors' roles in homeostatic responses is observable when 1. an increase in body temperature results from exercise. 2. an increase in body temperature results from fever. 3. an increase in body temperature results from involuntary shivering. 4. the rising sun causes an increase in body temperature in a stationary animal. 5. a decrease in body temperature results from shock.

an increase in body temperature results from involuntary shivering.

All hormones 1. are carried to target cells in the blood. 2. are produced by endocrine glands. 3. are lipid-soluble molecules. 4. are protein molecules. 5. elicit the same biological response from all of their target cell

are carried to target cells in the blood.

Most land-dwelling invertebrates and all of the amphibians 1. are ectothermic organisms with variable body temperatures. 2. alter their metabolic rates to maintain a constant body temperature of 37°C. 3. become more active when environmental temperatures drop below 15°C. 4. have a net loss of heat across a moist body surface, even in direct sun. 5. are endotherms but become thermoconformers only when they are in water.

are ectothermic organisms with variable body temperatures.

Receptors for nonsteroid hormones are located in _____. the extracellular fluid the cytoplasm the nucleus the cytosol association with a cell's plasma membrane

association with a cell's plasma membrane

Hormones are _____. 1. always proteins 2. produced only in response to environmental stress 3. chemical signals between cells, transported in blood or hemolymph 4. are all under the control of the pituitary gland 5. signals that must interact with DNA in order to be effective

chemical signals between cells, transported in blood or hemolymph

The body tissue that consists largely of material located outside of cells is epithelial tissue connective tissue smooth muscle nervous tissue skeletal muscle

connective tissue

A neuron consists of _____. a cell body only dendrites only axons only dendrites, a cell body, and axons striations

dendrites, a cell body, and axons

Homeostasis typically relies on negative feedback because positive feedback 1. involves one location rather than several across the body 2. acts within, but not beyond, a normal range 3. requires a response but not a stimulus 4. drives processes to completion rather than to a balance point 5. can decrease but not increase a variable

drives processes to completion rather than to a balance point

Negative feedback is a method of homeostatic control that _____. 1. produces a response by lowering the set point of an organism's metabolism 2. operates independently of most signaling mechanisms 3. promotes decreases in metabolic rate rather than increases 4. increases the speed and rapidity of negative responses to environmental stimuli 5. ensures that conditions in an organism do not vary too much above or below their set points

ensures that conditions in an organism do not vary too much above or below their set points

Which of these is a nonsteroid hormone? estrogen testosterone both estrogen and testosterone oxytocin epinephrine and oxytocin

epinephrine and oxytocin

Which of these extracellular signal molecules could diffuse through a plasma membrane and bind to an intracellular receptor? estrogen epinephrine cellulose oxytocin starch

estrogen

Humans can lose, but cannot gain, heat through the process of radiation. conduction. metabolism. evaporation. convection.

evaporation

Panting by an overheated dog achieves cooling by acclimatization. torpor. nonshivering thermogenesis. evaporation. shivering thermogenesis.

evaporation.

The panting responses that are observed in overheated birds and mammals dissipates excess heat by evaporation. hibernation. vasoconstriction. acclimation. countercurrent exchange.

evaporation.

Which process in the nephron is least selective? reabsorption filtration active transport salt pumping by the loop of Henle secretion

filtration

The body's automatic tendency to maintain a constant and optimal internal environment is termed static equilibrium. balanced equilibrium. physiological chance. homeostasis. estivation.

homeostasis.

The temperature-regulating center of vertebrate animals is located in the subcutaneous layer of the skin. liver. hypothalamus. thyroid gland. medulla oblongata.

hypothalamus.

In a survivably cold environment, an ectotherm is more likely to survive an extended period of food deprivation than would an equally sized endotherm because the ectotherm 1. expends more energy per kg of body mass than does the endotherm. 2. invests little energy in temperature regulation. 3. metabolizes its stored energy more readily than can the endotherm. 4. maintains a higher basal metabolic rate. 5. has greater insulation on its body surface.

invests little energy in temperature regulation.

Seasonal changes in snake activity are due to the fact that the snake 1. is more active in summer because that is the period for mating. 2. is more active in summer because it can gain body heat by conduction. 3. is less active in winter because the food supply is decreased. 4. is less active in winter because it does not need to avoid predators. 5. is more active in summer as a result of being disturbed by other animals.

is more active in summer because it can gain body heat by conduction.

In their mechanism of action, a difference between lipid-soluble and water-soluble hormones is that _____. 1. lipid-soluble hormones bind to an intracellular receptor and this hormone-receptor complex binds to DNA 2. water-soluble hormones cross the plasma membrane more readily than do lipid-soluble hormones 3. water-soluble hormones bind reversibly to DNA 4. lipid-soluble hormones activate a "second messenger" pathway 5. the water-soluble hormones travel only in the blood, and the lipid-soluble hormones travel only in the lymphatic fluid

lipid-soluble hormones bind to an intracellular receptor and this hormone-receptor complex binds to DNA

An exchange surface in direct contact with the external environment is found in the skeletal muscles. heart. liver. lungs. brain.

lungs

Homeostasis is the _____. 1. idea that all vertebrates are built in a similar way 2. maintenance of a relatively constant and optimal internal environment 3. cooperation of body parts to form tissues, organs, and systems 4. exchange of materials with the surrounding environment 5. correlation of structure and function

maintenance of a relatively constant and optimal internal environment

For hormones that homeostatically regulate cellular functions, 1. the circulating level of a hormone is held constant through a series of positive feedback loops. 2. endocrine organs release their contents into the bloodstream via specialized ducts. 3. both lipid-soluble hormones and water-soluble hormones bind to intracellular protein receptors. 4. negative feedback typically regulates hormone secretion. 5. it is impossible to also have neural regulation of that system.

negative feedback typically regulates hormone secretion.

How do nonsteroid hormones differ from steroid hormones? 1. nonsteroid hormones bind to a cell's DNA; steroid hormones do not bind to a cell's DNA 2. nonsteroid hormones act via signal transduction pathways; steroid hormones do not act via signal transduction pathways 3. the action of nonsteroid hormones never affects gene expression; the action of steroid hormones always affects gene expression 4. nonsteroid hormones bind to cytoplasmic receptors; steroid hormones bind to plasma membrane receptors 5. nonsteroid hormones are fat-soluble; steroid hormones are water-soluble

nonsteroid hormones act via signal transduction pathways; steroid hormones do not act via signal transduction pathways

The reason that the steroid hormone aldosterone affects only a small number of cells in the body is that 1. only its target cells contain aldosterone receptors. 2. nontarget cells convert aldosterone to a hormone to which they do respond. 3. only its target cells get exposed to aldosterone. 4. it is unable to enter nontarget cells. 5. nontarget cells destroy aldosterone before it can produce any effect.

only its target cells contain aldosterone receptors

A countercurrent heat exchanger enables an animal to _____. 1. absorb heat from the environment 2. reduce the loss of body heat to the environment 3. produce more heat when needed 4. slow metabolism when food is not available 5. increase heat loss by evaporation

reduce the loss of body heat to the environment

A cell with membrane-bound proteins that selectively bind a specific hormone is called that hormone's target cell. regulatory cell. plasma cell. endocrine cell. secretory cell.

target cell.

An example of a properly functioning homeostatic control system is seen when 1. the core body temperature of a runner rises gradually from 37°C to 45°C. 2. a blood cell shrinks when placed in a solution of salt and water. 3. the kidneys excrete salt into the urine when dietary salt levels rise. 4. the level of glucose in the blood is abnormally high whether or not a meal has been eaten. 5. the blood pressure increases in response to an increase in blood volume.

the kidneys excrete salt into the urine when dietary salt levels rise.

Steroid hormone-receptor complexes act in _____. the nucleus lysosomes vesicles the cytoplasm the plasma membrane

the nucleus

Positive feedback differs from negative feedback in that 1. the positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite to it. 2. positive feedback benefits the organism, whereas negative feedback is detrimental. 3. positive feedback systems have only effectors, whereas negative feedback systems have only receptors. 4. the effector's response increases some parameter (such as body temperature), whereas in negative feedback it can only decrease the parameter. 5. positive feedback systems have control centers that are lacking in negative feedback systems.

the positive feedback's effector responses are in the same direction as the initiating stimulus rather than opposite to it.

Most types of communication between cells utilize 1. a direct electrical connection between the cells. 2. the release of chemical signals by the cell sending the message. 3. the movement of the cells. 4. the exchange of cytosol between the cells. 5. the exchange of DNA between the cells.

the release of chemical signals by the cell sending the message.

Penguins, seals, and tuna have body forms that permit rapid swimming, because 1. all of their bodies have been compressed since birth by intensive underwater pressures. 2. all share a common ancestor at some point in the past. 3. this is the only shape that will allow them to maintain a constant body temperature in water. 4. flying, pregnancy, and gill-breathing all require similar adaptations in form. 5. the shape is a convergent evolutionary solution to the need to reduce drag while swimming.

the shape is a convergent evolutionary solution to the need to reduce drag while swimming.

When a steroid hormone and a peptide hormone exert similar effects on a population of target cells, then 1. the steroid and peptide hormones must use the same biochemical mechanisms. 2. the steroid hormones affect the synthesis of effector proteins, whereas peptide hormones activate effector proteins already present in the cell. 3. the steroid hormones affect only the release of proteins from the target cell, whereas peptide hormones affect only the synthesis of proteins that remain in the target cell. 4. the steroid and peptide hormones must bind to the same receptor protein. 5. the steroid hormones affect the activity of certain proteins within the cell, whereas peptide hormones directly affect the processing of mRNA.

the steroid hormones affect the synthesis of effector proteins, whereas peptide hormones activate effector proteins already present in the cell.

The primary reason steroid hormones usually act slowly is that _____. 1. they are produced at very low concentrations 2. acting via a signal transduction pathway makes for slower responses than does directly interacting with a cell's DNA 3. they are too large to enter a cell and therefore must first bind to a plasma membrane receptor before having an effect on a cell 4. target cells tend to ignore steroid hormones in favor of nonsteroid hormones 5. they turn genes on or off and it takes time for gene products to build up or become depleted

they turn genes on or off and it takes time for gene products to build up or become depleted

Nervous tissue functions _____. as a physical barrier to the invasion of pathogens to physically move the body to sense stimuli to physically support the body in the absorption of nutrients

to sense stimuli

Hormones that promote homeostasis 1. usually operate as part of a negative feedback system. 2. travel to target cells without passage in the plasma. 3. utilize receptors that bind any hormone. 4. initiate signal transduction in the target cell without binding to receptors. 5. are not found as members of antagonistic signaling mechanisms.

usually operate as part of a negative feedback system.

Which of the following would increase the rate of heat exchange between an animal and its environment? countercurrent heat exchanger wind blowing across the body surface vasoconstriction blubber or fat layer feathers or fur

wind blowing across the body surface