Bio Exam 3 Spring
Single-celled Paramecium live in pond water (a hypotonic environment). They have a structural feature, a contractile vacuole, which enables them to osmoregulate. If you observed them in the following solutions, at which sucrose concentration (in millimolars, mM) would you expect the contractile vacuole to be most active? A) 0.0 mM sucrose B) 0.05 mM saline C) 0.08 mM sucrose D) 1.0 mM saline
A) 0.0 mM sucrose
Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal? A) Voltage-gated calcium channels in the membrane open. B) Synaptic vesicles fuse with the membrane. C) The postsynaptic cell produces an action potential. D) Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft.
A) Voltage-gated calcium channels in the membrane open.
If you are hiking through the desert for several days, one would pack which of the following to ensure proper hydration? A) a drink with a combination of water and electrolytes B) caffeinated beverages C) bottled water kept at room temperature D) bottled water that had been frozen to ensure that it would be as cold as possible
A) a drink with a combination of water and electrolytes
Self-propagation and refractory periods (states) are typical of _____. A) action potentials B) graded hyperpolarizations C) excitatory postsynaptic potentials D) threshold potentials
A) action potentials
Which process in the nephron is LEAST selective? A) filtration B) reabsorption C) active transport D) secretion
A) filtration
Ionotropic receptors found at synapses are operated via _____. A) ligand-gated ion channels B) electrical synapses C) inhibitory, but not excitatory, synapses D) excitatory, but not inhibitory, synapses
A) ligand-gated ion channels
Urea is produced in the _____. A) liver from NH3 and carbon dioxide B) liver from glycogen C) kidneys from glycerol and fatty acids D) bladder from uric acid and water
A) liver from NH3 and carbon dioxide
The necropsy (postmortem analysis) of a freshwater fish that died after being placed accidentally in saltwater would likely show that _____. A) loss of water by osmosis from cells in vital organs resulted in cell death and organ failure B) high amounts of salt had diffused into the fish's cells, causing them to swell and lyse C) the kidneys were not able to keep up with the water removal necessary in this hyperosmotic environment, creating an irrevocable loss of homeostasis D) the gills became encrusted with salt, resulting in inadequate gas exchange and a resulting asphyxiation
A) loss of water by osmosis from cells in vital organs resulted in cell death and organ failure
Although the membrane of a "resting" neuron is highly permeable to potassium ions, its membrane potential does not exactly match the equilibrium potential for potassium because the neuronal membrane is also _____. A) slightly permeable to sodium ions B) fully permeable to calcium ions C) impermeable to sodium ions D) highly permeable to chloride ions
A) slightly permeable to sodium ions
Through studies of insect Malpighian tubules, researchers found that K+ accumulated on the inner face of the tubule, against its concentration gradient. What can you infer about the mechanism of transport? A) Potassium transport is a passive process. B) Movement of potassium into the lumen of the Malpighian tubules is an energy-requiring process. C) Potassium moves out of the tubules at a faster rate than it moves into the lumen of the tubules. D) Sodium ions will follow potassium ions.
B) Movement of potassium into the lumen of the Malpighian tubules is an energy-requiring process.
Why are the renal artery and vein critical to the process of osmoregulation in vertebrates? A) The kidneys require constant and abnormally high oxygen supply to function. B) The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from the kidneys. C) The kidneys require higher than normal levels of hormones. D) The renal artery and vein are the main pathways regulating how much is produced by the kidneys
B) The renal artery delivers blood with nitrogenous waste to the kidney and the renal vein brings blood with less nitrogenous wastes away from the kidneys.
Acetylcholine released into the junction between a motor neuron and a skeletal muscle binds to a sodium channel and opens it. This is an example of _____. A) a voltage-gated potassium channel B) a ligand-gated sodium channel C) a second-messenger-gated sodium channel D) a chemical that inhibits action potentials
B) a ligand-gated sodium channel
The loop of Henle dips into the renal cortex. This is an important feature of osmoregulation in terrestrial vertebrates because _____. A) absorptive processes taking place in the loop of Henle are hormonally regulated B) differential permeabilities of ascending and descending limbs of the loop of Henle are important in establishing an osmotic gradient C) the loop of Henle plays an important role in detoxification D) additional filtration takes place along the loop of Henle
B) differential permeabilities of ascending and descending limbs of the loop of Henle are important in establishing an osmotic gradient
For a neuron with an initial membrane potential at -70 mV, an increase in the movement of potassium ions out of that neuron's cytoplasm would result in the _____. A) depolarization of the neuron B) hyperpolarization of the neuron C) replacement of potassium ions with sodium ions D) replacement of potassium ions with calcium ions
B) hyperpolarization of the neuron
How could you increase the magnitude of inhibitory postsynaptic potentials (IPSPs) generated at a synapse? A) increase sodium-potassium pump activity B) increase K+ permeability C) increase the influx of calcium D) All of the listed responses are correct.
B) increase K+ permeability
If ATP production in a human kidney was suddenly halted, urine production would _____. A) decrease, and the urine would be hypoosmotic compared to plasma B) increase, and the urine would be isoosmotic compared to plasma C) increase, and the urine would be hyperosmotic compared to plasma D) decrease, and the urine would be isoosmotic compared to plasma
B) increase, and the urine would be isoosmotic compared to plasma
The motor (somatic nervous) system can alter the activities of its targets, the skeletal muscle fibers, because _____. A) it is electrically coupled by gap junctions to the muscles B) its signals bind to receptor proteins on the muscles C) its signals reach the muscles via the blood D) it is connected to the internal neural network of the muscles
B) its signals bind to receptor proteins on the muscles
After blood flow is artificially reduced at one kidney, you would expect that kidney to secrete more of the hormone known as _____. A) angiotensinogen B) renin C) antidiuretic hormone D) atrial natriuretic peptide
B) renin
Osmoregulatory adjustment via the renin-angiotensin-aldosterone system can be triggered by _____. A) sleeping for one hour B) severe sweating on a hot day C) eating a pizza with olives and pepperoni D) drinking several glasses of water
B) severe sweating on a hot day
Increased antidiuretic hormone (ADH) secretion is likely after _____. A) drinking lots of pure water B) sweating-induced dehydration increases plasma osmolarity C) eating a small sugary snack D) blood pressure becomes abnormally high
B) sweating-induced dehydration increases plasma osmolarity
What is the function of the osmotic gradient found in the kidney? The osmotic gradient allows for _____. A) electrolytes to move from low to high concentrations in the absence of ATP B) the precise control of the retention of water and electrolytes C) the loop of Henle to deliver water to the renal vein D) the filtration of large cells at the glomerulus
B) the precise control of the retention of water and electrolytes
Urea is _____. A) insoluble in water B) the primary nitrogenous waste product of humans C) the primary nitrogenous waste product of most birds D) the primary nitrogenous waste product of most aquatic invertebrates
B) the primary nitrogenous waste product of humans
A primary reason that the kidneys have one of the highest metabolic rates of all body organs is that _____. A) they have membranes of varying permeability to water B) they operate an extensive set of active-transport ion pumps C) they are the body's only means of shedding excess nutrients D) they have an abundance of myogenic smooth muscle
B) they operate an extensive set of active-transport ion pumps
The force driving simple diffusion is _____, while the energy source for active transport is _____. A) the concentration gradient; ADP B) the concentration gradient; ATP C) transmembrane pumps; electron transport D) phosphorylated protein carriers; ATP
B.) the concentration gradient; ATP
The following steps refer to various stages in transmission at a chemical synapse. 1. Neurotransmitter binds with receptors associated with the postsynaptic membrane. 2. Calcium ions rush into neuron's cytoplasm. 3. An action potential depolarizes the membrane of the presynaptic axon terminal. 4. The ligand-gated ion channels open. 5. The synaptic vesicles release neurotransmitter into the synaptic cleft. Which sequence of events is correct? A) 1 → 2 → 3 → 4 → 5 B) 2 → 3 → 5 → 4 → 1 C) 3 → 2 → 5 → 1 → 4 D) 4 → 3 → 1 → 2 → 5
C) 3 → 2 → 5 → 1 → 4
What happens if twice as many inhibitory postsynaptic potentials (IPSPs) as excitatory postsynaptic potentials (EPSPs) arrive at a postsynaptic neuron in close proximity? A) A stronger action potential results. B) A weaker action potential results. C) No action potential results.
C) No action potential results.
A potassium ion gradient is set up in insect Malpighian tubules through an active transport process. As a result, potassium concentration is higher in the lumen of the tubules than in hemolymph. How would the potassium gradient affect water movement? A) Water would be forced out of the lumen of the Malpighian tubules through an osmotic gradient. B) The potassium gradient would have no effect on water movement. C) There would be a net movement of water into the lumen of the tubules. D) Water would be conserved, forming a hypertonic solution in the Malpighian tubules.
C) There would be a net movement of water into the lumen of the tubules.
Which of the following animals generally has the lowest volume of urine production? A) a vampire bat B) a salmon in fresh water C) a marine bony fish D) a shark inhabiting the Mississippi River
C) a marine bony fish
Low selectivity of solute movement is a characteristic of _____. A) H+ pumping to control pH B) reabsorption mechanisms along the proximal tubule C) filtration from the glomerular capillaries D) secretion along the distal tubule
C) filtration from the glomerular capillaries
After drinking alcoholic beverages, increased urine excretion is the result of _____. A) increased aldosterone production B) increased blood pressure C) inhibited secretion of antidiuretic hormone (ADH) D) increased reabsorption of water in the proximal tubule
C) inhibited secretion of antidiuretic hormone (ADH)
Most of the neurons in the human brain are _____. A) sensory neurons B) motor neurons C) interneurons D) peripheral neurons
C) interneurons
The point of connection between two communicating neurons is called the _____. A) axon hillock B) dendrite C) synapse D) cell body
C) synapse
To maintain homeostasis freshwater fish must _____. A) excrete large quantities of electrolytes B) consume large quantities of water C) excrete large quantities of water D) take in electrolytes through simple diffusion
C.) excrete large quantities of water
Opening all of the sodium channels on an otherwise typical neuron, with all other ion channels closed (which is an admittedly artificial setting), should move its membrane potential to _____. A) -90 mV B) 0 mV C) +30 mV D) +62 mV
D) +62 mV
One of the waste products that accumulates during cellular functions is carbon dioxide. It is removed via the respiratory system. What is another waste product that accumulates during normal physiological functions in vertebrates? I) ammonia II) uric acid III) urea A) only I and III B) only II and III C) only I and II D) I, II, and III
D) I, II, and III
In a resting potential, an example of a cation that is more abundant as a solute in the cytosol of a neuron than it is in the interstitial fluid outside the neuron is _____. A) Cl- B) Ca++ C) Na+ D) K+
D) K+
The activity of acetylcholine in a synapse is terminated by its_____. A) diffusion across the presynaptic membrane B) active transport across the postsynaptic membrane C) diffusion across the postsynaptic membrane D) degradation on the postsynaptic membrane
D) degradation on the postsynaptic membrane
Neurotransmitters are released from axon terminals via _____. A) osmosis B) active transport C) diffusion D) exocytosis
D) exocytosis
A simple nervous system _____. A) must include chemical senses, mechanoreception, and vision B) includes a minimum of twelve effector neurons C) has information flow in only one direction: away from an integrating center D) includes sensory information, an integrating center, and effectors
D) includes sensory information, an integrating center, and effectors
A graded hyperpolarization of a membrane can be induced by _____. A) increasing its membrane's permeability to Na+ B) decreasing its membrane's permeability to Cl- C) increasing its membrane's permeability to Ca++ D) increasing its membrane's permeability to K+
D) increasing its membrane's permeability to K+
The operation of the sodium-potassium "pump" moves _____. A) sodium and potassium ions into the cell B) sodium and potassium ions out of the cell C) sodium ions into the cell and potassium ions out of the cell D) sodium ions out of the cell and potassium ions into the cell
D) sodium ions out of the cell and potassium ions into the cell
Which nitrogenous waste has the greatest number of nitrogen atoms? A) ammonia B) ammonium ions C) urea D) uric acid
D) uric acid