BIOG 1440 Prelim 2 Pre-Class Questions
When the air in a testing chamber is specially mixed so that its oxygen content is 10 percent and its overall air pressure is 400 mm Hg, then PO2 is _____. - 400 mm Hg - 82 mm Hg - 40 mm Hg - 4 mm Hg
40 mm Hg
A stroke volume of 70 mL/cycle in a heart with a pulse of 72 cycles per minute results in a cardiac output of about _____. - 5 liters per minute - 50 liters per minute - 50 milliliters per minute - 0.5 liters per minute
5 liters per minute
Which of the following is the correct sequence that describes the excitation and contraction of a skeletal muscle fiber? 1. Tropomyosin shifts and unblocks the cross-bridge binding sites. 2. Calcium is released and binds to the troponin complex. 3. Transverse tubules depolarize the sarcoplasmic reticulum. 4. The thin filaments are ratcheted across the thick filaments by the heads of the myosin molecules using energy from ATP. 5. An action potential in a motor neuron causes the axon to release acetylcholine, which depolarizes the muscle cell membrane. - 2 → 1 → 3 → 5 → 4 - 2 → 3 → 4 → 1 → 5 - 1 → 2 → 3 → 4 → 5 - 5 → 3 → 2 → 1 → 4
5 → 3 → 2 → 1 → 4
At the summit of a high mountain, the atmospheric pressure is 380 mm Hg. If the atmosphere is still composed of 21percent oxygen, then the partial pressure of oxygen at this altitude is about _____. - 380 mm Hg - 80 mm Hg - 760 mm Hg - 160 mm Hg
80 mm Hg
Which of the following best describes an artery? - Arteries carry blood away from capillaries. - Arteries carry oxygenated blood. - Arteries contain valves. - Arteries have thin walls compared with veins. - Arteries carry blood away from the heart.
Arteries carry blood away from the heart
Salmon eggs hatch in freshwater. The fish then migrate to the ocean (a hypertonic solution) and, after several years of feeding and growing, return to freshwater to breed. How can these organisms make the transition from freshwater to ocean water and back to freshwater? - The rectal gland functions in the ocean water, and chloride cells function in freshwater. - Their metabolism changes in salt water to degrade electrolytes. - Different gill cells are involved in osmoregulation in freshwater than in salt water. - Salmon in freshwater excrete concentrated urine, and salmon in salt water excrete dilute urine.
Different gill cells are involved in osmoregulation in freshwater than in salt water.
How has the avian lung adapted to the metabolic demands of flight? - Airflow through the avian lung is bidirectional like in mammals. - Countercurrent circulation is present in the avian lung. - There is more dead space within the avian lung so that oxygen can be stored for future use. - Gas exchange occurs during both inhalation and exhalation.
Gas exchange occurs during both inhalation and exhalation.
A patient is hospitalized with muscle spasms caused by failure of back muscles to relax after contraction. Which of the following would be most likely to help? - Increase the amount of acetylcholine at the synapses between motor neurons and muscle cells. - Induce tropomycin and troponin to bind to the myosin binding sites on actin. - Inject calcium into the muscle cell, because it is not being released from the sarcoplasmic reticulum. - Depolarize the motor neurons to send an action potential to the muscle cells.
Induce tropomycin and troponin to bind to the myosin binding sites on actin.
What would happen to people exposed to a chemical warfare agent that blocked acetylcholine from binding to muscle receptors? - Action potentials would be continuously generated, causing convulsive muscle contractions; muscle contractions would then be prevented, causing paralysis. - Muscle contractions would be prevented, causing paralysis. - Muscle contractions could still occur, but relaxation of the muscle would be impaired. - Action potentials would be continuously generated, causing convulsive muscle contractions.
Muscle contractions would be prevented, causing paralysis.
Which of the following statements comparing respiration in fish and in mammals is correct? - The respiratory medium for fish carries more oxygen than the respiratory medium of mammals. - In blood, oxygen is primarily transported by plasma in fish, but by red blood cells in mammals. - A countercurrent exchange mechanism between the respiratory medium and blood flow is seen in mammals but not in fish. - The movement of the respiratory medium in mammals is bidirectional, but in fish it is unidirectional.
The movement of the respiratory medium in mammals is bidirectional, but in fish it is unidirectional.
A rabbit taken from a meadow near sea level and moved to a meadow high on a mountainside would have some trouble breathing. Why? - The percentage of oxygen in the air at high elevations is higher than at sea level. - The percentage of oxygen in the air at high elevations is lower than at sea level. - The partial pressure of oxygen in the air at high elevations is higher than at sea level. - The partial pressure of oxygen in the air at high elevations is lower than at sea level.
The partial pressure of oxygen in the air at high elevations is lower than at sea level.
Blood is pumped at high pressures in arteries from the heart to ensure that all parts of the body receive adequate blood flow. Capillary beds, however, would hemorrhage under direct arterial pressures. How does the design of the circulatory network contribute to reducing blood pressure to avoid this scenario? - The total cross-sectional diameter of the arterial circulation increases with progression from artery to arteriole to capillary, leading to a reduced blood pressure. - Capillary beds have the thickest walls of any blood vessel to resist these high pressures. - Fluid loss from the arteries is high enough that pressure drops off significantly by the time blood reaches the capillaries. - Blood flow through the capillaries is essentially frictionless, and this reduces the amount of pressure on their walls.
The total cross-sectional diameter of the arterial circulation increases with progression from artery to arteriole to capillary, leading to a reduced blood pressure.
Sharks live in seawater. Their tissues are isotonic to seawater, but their concentrations of sodium ions, potassium ions, and chloride ions in cells and extracellular fluids are similar to those of freshwater fishes. How is that possible? - Metabolic intermediates of sharks tie up intracellular chloride and potassium ions. - Their blood is hypotonic to their tissues. - They excrete large quantities of electrolytes. - Urea and trimethylamine oxide contribute to intra- and extracellular osmolarity in shark tissues.
Urea and trimethylamine oxide contribute to intra- and extracellular osmolarity in shark tissues.
Organisms with a circulating body fluid that is distinct from the fluid that directly surrounds the body's cells are likely to have _____. - a closed circulatory system - an open circulatory system - a gastrovascular cavity - branched tracheae
a closed circulatory system
The sun shining on a tidal pool during a hot day heats the water. As some water evaporates, the pool becomes saltier, causing _____. - a decrease in the water's density - a decrease in its oxygen content - an increase in its ability to sustain aerobic organisms - an increase in its carbon dioxide content
a decrease in its oxygen content
You are a physician, and you are seeing a patient who complains of abnormal fatigue during exercise. You find that the immediate problem is a buildup of carbon dioxide in the tissues. What is the most likely cause? - abnormally shaped platelets - abnormal carbonic anhydrase - not enough hemoglobin - abnormal hemoglobin
abnormal carbonic anhydrase
An anthropologist discovers the fossilized heart of an extinct animal. The evidence indicates that the organism's heart was large, was well-formed, and had four chambers, with no connection between the right and left sides. A reasonable conclusion supported by these observations is that the _____. - animal was endothermic and had a high metabolic rate - animal was most closely related to alligators and crocodiles - animal had evolved from birds - species had little to no need to regulate blood pressure
animal was endothermic and had a high metabolic rate
Which of the following conditions would most likely be due to high blood pressure in a mammal? - reversal of normal blood flow direction in arteries - inability of the right ventricle to contract - destruction of red blood cells - bursting of blood vessels in capillary beds
bursting of blood vessels in capillary beds
During most daily activities, the human respiration rate is most closely linked to the blood levels of _____. - carbon dioxide - carbon monoxide - nitrogen - oxygen
carbon dioxide
Most of the carbon dioxide produced by humans is _____. - converted to bicarbonate ions by an enzyme in red blood cells - transported in the erythrocytes as carbonic acid - bound to hemoglobin - simply dissolved in the plasma
converted to bicarbonate ions by an enzyme in red blood cells
Large proteins such as albumin remain in capillaries rather than diffusing out, resulting in the _____. - development of an osmotic pressure difference across capillary walls - loss of fluid from capillaries - increased diffusion of hemoglobin - loss of osmotic pressure in the capillaries
development of an osmotic pressure difference across capillary walls
The loop of Henle dips into the renal cortex. This is an important feature of osmoregulation in terrestrial vertebrates because _____. - absorptive processes taking place in the loop of Henle are hormonally regulated - differential permeabilities of ascending and descending limbs of the loop of Henle are important in establishing an osmotic gradient - additional filtration takes place along the loop of Henle - the loop of Henle plays an important role in detoxification
differential permeabilities of ascending and descending limbs of the loop of Henle are important in establishing an osmotic gradient
Countercurrent exchange in the fish gill helps to maximize _____. - osmosis - diffusion - active transport - blood pressure
diffusion
A skeletal muscle deprived of adequate ATP supplies will _____. - fire many more action potentials than usual and enter a state of "rigor" - enter a state where actin and myosin are unable to separate - immediately relax - sequester all free calcium ions into the sarcoplasmic reticulum
enter a state where actin and myosin are unable to separate
To adjust blood pressure independently in the capillaries of the gas-exchange surface and in the capillaries of the general body circulation, an organism would need a(n) _____. - hemocoel - four-chambered heart - open circulatory system - two-chambered heart
four-chambered heart
In which of the following organisms does blood flow from the pulmocutaneous circulation to the heart before circulating through the rest of the body? - fishes - annelids - insects - frogs
frogs
A decrease from pH 7.4 to pH 7.2 causes hemoglobin to _____. - give up more of its oxygen molecules - increase its binding of carbon dioxide molecules - bind more oxygen molecules - release all bound carbon dioxide molecules
give up more of its oxygen molecules
In which of the following animals are the blood and the interstitial fluid considered to be the same body fluid? - fishes - dogs - jellyfish and cnidarians - sparrows - grasshoppers
grasshoppers
Excretory organs known as Malpighian tubules are present in _____. - sea stars - insects - jellyfish - flatworms
insects
Ammonia _____. - has low toxicity relative to urea - is soluble in water - is the major nitrogenous waste excreted by insects - is metabolically more expensive to synthesize than urea
is soluble in water
Compared to the seawater around them, most marine invertebrates are _____. - hypoosmotic - hyperosmotic and isoosmotic - hyperosmotic - isoosmotic
isosmotic
Compared to wetland mammals, water conservation in mammals of arid regions is enhanced by having more _____. - urinary bladders - ureters - juxtamedullary nephrons - podocytes
juxtamedullary nephrons
Urea is produced in the _____. - bladder from uric acid and water - kidneys from glycerol and fatty acids - liver from glycogen - liver from NH3 and carbon dioxide
liver from NH3 and carbon dioxide
Ammonia is likely to be the primary nitrogenous waste in living conditions that include _____. - a terrestrial environment, such as that supporting crickets - lots of fresh water flowing across the gills of a fish - lots of seawater, such as a bird living in a marine environment - a moist system of burrows, such as those of naked mole rats
lots of fresh water flowing across the gills of a fish
Processing of filtrate in the proximal and distal tubules _____. - achieves the conversion of toxic ammonia to less toxic urea - regulates the speed of blood flow through the nephrons - reabsorbs urea to maintain osmotic balance - maintains homeostasis of pH in body fluids
maintains homeostasis of pH in body fluids
Osmoregulation and excretion are _____. - chemical processes that completely stop during torpor and hibernation - mechanisms for the homeostatic control of body temperature - mechanisms that maintain volume and composition of body fluids - ways that animals control their external environment - mechanisms that require continual water loss
mechanisms that maintain volume and composition of body fluids
The contraction of skeletal muscles is based on _____. - myosin cross-bridges binding to actin and transitioning from a high-energy to a low-energy state - actin cross-bridges binding to myosin and transitioning from a high-energy to a low-energy state - myosin filaments coiling up to become shorter - actin and myosin filaments both coiling up to become shorter
myosin cross-bridges binding to actin and transitioning from a high-energy to a low-energy state
In an open circulatory system, blood is _____. - not always confined to blood vessels and is under higher pressure than in closed circulatory systems - always inside of vessels and is under lower pressure than in closed circulatory systems - not always confined to blood vessels and is under lower pressure than in closed circulatory systems - always inside of vessels and is under higher pressure than in closed circulatory systems
not always confined to blood vessels and is under lower pressure than in closed circulatory systems
Which of the following are present in high densities in both smooth and skeletal muscle cells? I) cilia II) mitochondria III) nuclei IV) endoplasmic reticulum - only I and II - only III and IV - only II and IV - only I, II, and III
only II and IV
Terrestrial animals are _____. - usually nocturnal - likely to have the same problems with osmoregulation as do freshwater fish - osmoregulators that must obtain water from the environment - obligated to protect their eggs from drying with water-resistant shells - either arthropods or vertebrates
osmoregulators that must obtain water from the environment
The Bohr shift on the oxygen-hemoglobin dissociation curve is produced by changes in _____. - the partial pressure of oxygen - pH - hemoglobin concentration - temperature
pH
In animals, nitrogenous wastes are produced mostly from the catabolism of _____. - starch and cellulose - proteins and nucleic acids - phospholipids and glycolipids - triglycerides and steroids
proteins and nucleic acids
Birds, insects, and many reptiles excrete nitrogenous waste in the form of uric acid, which _____. - is not very toxic compared to other nitrogenous wastes, but requires the loss of a lot of water with its excretion - reduces water loss compared to other nitrogenous wastes, but requires more metabolic energy to produce - is much more soluble in water than other nitrogenous wastes, but is energetically costlier than other nitrogenous wastes to synthesize - reduces water loss compared to other nitrogenous wastes, but is highly toxic - reduces energy use compared to other nitrogenous wastes, but is highly toxic to animals that produce it
reduces water loss compared to other nitrogenous wastes, but requires more metabolic energy to produce
The fluid with the highest osmolarity is _____. - seawater in a tidal pool - plasma in mammals - plasma in birds - distilled water
seawater in a tidal pool
An appropriate group of animals to examine to observe a Malpighian tubule would be _____. - the amphibians - the annelids - the flatworms - the birds - the insects
the insects
Carbon dioxide levels in the blood and cerebrospinal fluid affect pH. This enables the organism to sense a disturbance in gas levels as _____. - the brain directly measures and monitors oxygen levels and causes breathing changes accordingly - the brain alters the pH of the cerebrospinal fluid to force the animal to retain more or less carbon dioxide - stretch receptors in the lungs cause the medulla oblongata to speed up or slow breathing - the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and uses this measure to control breathing
the medulla oblongata, which is in contact with cerebrospinal fluid, monitors pH and uses this measure to control breathing
What is the function of the osmotic gradient found in the kidney? The osmotic gradient allows for _____. - electrolytes to move from low to high concentrations in the absence of ATP - the precise control of the retention of water and electrolytes - the filtration of large cells at the glomerulus - the loop of Henle to deliver water to the renal vein
the precise control of the retention of water and electrolytes
Urea is _____. - the primary nitrogenous waste product of most birds - insoluble in water - the primary nitrogenous waste product of humans - the primary nitrogenous waste product of most aquatic invertebrates
the primary nitrogenous waste product of humans
The greatest difference in the concentration of respiratory gases is found in which of the following pairs of mammalian blood vessels? - the pulmonary vein and the aorta - the pulmonary vein and the jugular vein - the pulmonary artery and the inferior vena cava - the veins from the right and left legs
the pulmonary vein and the jugular vein
Circulatory systems compensate for _____. - the slow rate at which diffusion occurs over large distances - temperature differences between the lungs and the active tissue - the need to cushion animals from trauma - the problem of communication systems involving only the nervous system
the slow rate at which diffusion occurs over large distances
The velocity of blood flow is the lowest in capillaries because _____. - the diastolic blood pressure is too low to deliver blood to the capillaries at a high flow rate - the total cross-sectional area of the capillaries is greater than the total cross-sectional area of the arteries or any other part of the circulatory system - the capillaries have internal valves that slow the flow of blood - the systemic capillaries are supplied by the left ventricle, which has a lower cardiac output than the right ventricle
the total cross-sectional area of the capillaries is greater than the total cross-sectional area of the arteries or any other part of the circulatory system
Within a normally functioning kidney, blood can be found in _____. - the proximal tubule - the vasa recta - the collecting duct - Bowman's capsule
the vasa recta
A human red blood cell in an artery of the left arm is on its way to deliver oxygen to a cell in the thumb. To travel from the artery to the thumb and then back to the left ventricle, this red blood cell must pass through _____. - four capillary beds - one capillary bed - three capillary beds - two capillary beds
two capillary beds
The advantage of excreting nitrogenous wastes as urea rather than as ammonia is that _____. - urea does not affect the osmolar gradient - urea is less toxic than ammonia - urea can be exchanged for Na+ - less nitrogen is removed from the body
urea is less toxic than ammonia
As a result of the non-selectivity of the kidney's filtration of small molecules, _____. - the proportions of all the substances in the blood are the same as in the urine - urine is always much less concentrated than blood - many useful substances are lost in the urine - the kidneys have little control over body fluid composition - useful substances must be selectively reabsorbed
useful substances must be selectively reabsorbed
Which of the following is the correct sequence of blood flow in birds and mammals? - pulmonary vein → left atrium → left ventricle pulmonary circuit - vena cava → right atrium → right ventricle pulmonary vein - left ventricle → aorta → lungs → systemic circulation - vena cava → right atrium → right ventricle pulmonary artery
vena cava → right atrium → right ventricle pulmonary artery
Which of the following events would be predicted by the Bohr shift effect as the amount of carbon dioxide released from your tissues into the blood capillaries increases? The amount of oxygen in _____. - venous blood would decrease - arterial blood would decrease - arterial blood would increase - venous blood would increase
venous blood would decrease
