Question 1

Table 40.1
-What role does Na+/K+- ATPase play in salt excretion by the shark rectal gland?

Accepted Answer

A)  Na+/K+- ATPase pumps sodium into and potassium out of cells across the basolateral membrane. 
B)  Na+/K+- ATPase pumps sodium out and potassium into cells across the basolateral membrane. 
C)  Na+/K+- ATPase pumps sodium out and potassium into cells across the apical membrane. 
D)  Na+/K+- ATPase pumps sodium into and potassium out of cells across the apical membrane. 
A)  Na+/K+- ATPase pumps sodium into and potassium out of cells across the basolateral membrane. 
B)  Na+/K+- ATPase pumps sodium out and potassium into cells across the basolateral membrane. 
C)  Na+/K+- ATPase pumps sodium out and potassium into cells across the apical membrane. 
D)  Na+/K+- ATPase pumps sodium into and potassium out of cells across the apical membrane.

Question 2

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?

Accepted Answer

A)  They excrete large quantities of electrolytes. 
B)  Metabolic intermediates of sharks tie up intracellular chloride and potassium ions. 
C)  Their blood is hypotonic to their tissues. 
D)  There are other compounds contributing to intra- and extracellular osmolarity in shark tissues. 
A)  They excrete large quantities of electrolytes. 
B)  Metabolic intermediates of sharks tie up intracellular chloride and potassium ions. 
C)  Their blood is hypotonic to their tissues. 
D)  There are other compounds contributing to intra- and extracellular osmolarity in shark tissues.

Question 3

Which of the following affects the osmolarity of a solution?

Accepted Answer

A)  water concentration 
B)  salt concentration 
C)  glucose concentration 
D)  all of the above 
A)  water concentration 
B)  salt concentration 
C)  glucose concentration 
D)  all of the above

Question 4

Which of the following is a function of antidiuretic hormone ADH)?

Accepted Answer

A)  ADH alters the ion reabsorption by the loop of Henle. 
B)  ADH decreases the reabsorption of urea, creating a higher urea content in the urine. 
C)  ADH improves the reabsorption of glucose by the proximal convoluted tubule. 
D)  ADH triggers the insertion of water channels called aquaporins, thereby increasing the amount of water reabsorbed by the collecting duct. 
E)  ADH triggers the insertion of water channels called aquaporins, thereby reducing the amount of water reabsorbed by the collecting duct. 
A)  ADH alters the ion reabsorption by the loop of Henle. 
B)  ADH decreases the reabsorption of urea, creating a higher urea content in the urine. 
C)  ADH improves the reabsorption of glucose by the proximal convoluted tubule. 
D)  ADH triggers the insertion of water channels called aquaporins, thereby increasing the amount of water reabsorbed by the collecting duct. 
E)  ADH triggers the insertion of water channels called aquaporins, thereby reducing the amount of water reabsorbed by the collecting duct.

Question 5

Terrestrial organisms lose water through evaporation. Why are desert locusts and flour beetles good organisms to use in studying mechanisms to regulate water loss?

Accepted Answer

A)  They have stoma that regulate water loss. 
B)  They live in environments where little to no water is available. 
C)  They are unable to ingest adequate amounts of sodium and chloride. 
D)  They have a relatively large surface area/volume relationship. 
A)  They have stoma that regulate water loss. 
B)  They live in environments where little to no water is available. 
C)  They are unable to ingest adequate amounts of sodium and chloride. 
D)  They have a relatively large surface area/volume relationship.

Question 6

Which of the following are soluble compounds that contribute to intracellular osmolarity in shark tissues?

Accepted Answer

A)  urea and trimethylamine oxide 
B)  glucose and amino acids 
C)  excessively high levels of sodium and chloride 
D)  a proton pump 
A)  urea and trimethylamine oxide 
B)  glucose and amino acids 
C)  excessively high levels of sodium and chloride 
D)  a proton pump

Question 7

The force driving simple diffusion is

Accepted Answer

A)  transmembrane pumps. 
B)  a concentration gradient. 
C)  phosphorylated protein carriers. 
D)  ATP. 
A)  transmembrane pumps. 
B)  a concentration gradient. 
C)  phosphorylated protein carriers. 
D)  ATP.

Question 8

What role do chloride cells play in osmoregulation of marine fish with bony skeletons?

Accepted Answer

A)  They are involved in excretion of excess salt. 
B)  They actively transport chloride into the gills. 
C)  They mediate the movement of salt from seawater through their gills. 
D)  They actively transport salt across the basolateral membrane of the rectal gland. 
A)  They are involved in excretion of excess salt. 
B)  They actively transport chloride into the gills. 
C)  They mediate the movement of salt from seawater through their gills. 
D)  They actively transport salt across the basolateral membrane of the rectal gland.

Question 9

Table 40.1
-The intercellular concentration of three electrolytes is compared with the concentration of these electrolytes in fluid eliminated from the shark rectal gland in Table 40.1. Based on the data, which of the following is a likely function of the rectal gland?

Accepted Answer

A)  The rectal gland eliminates metabolic waste. 
B)  The rectal gland is able to concentrate Na+, K+, and Cl- . 
C)  There is very little potassium in sharks. 
D)  Chloride levels in seawater are similar to those in shark tissues. 
A)  The rectal gland eliminates metabolic waste. 
B)  The rectal gland is able to concentrate Na+, K+, and Cl- . 
C)  There is very little potassium in sharks. 
D)  Chloride levels in seawater are similar to those in shark tissues.

Question 10

A necropsy postmortem analysis) of a marine sea star that died after it was mistakenly placed in freshwater would likely show that it died because

Accepted Answer

A)  its contractile vacuoles ruptured. 
B)  it was so hypertonic to the freshwater that it could not osmoregulate. 
C)  it was stressed and needed more time to acclimate to the new conditions. 
D)  its cells dehydrated and lost the ability to metabolize. 
E)  the sea star's kidneys could not handle the change in ionic content presented by the freshwater. 
A)  its contractile vacuoles ruptured. 
B)  it was so hypertonic to the freshwater that it could not osmoregulate. 
C)  it was stressed and needed more time to acclimate to the new conditions. 
D)  its cells dehydrated and lost the ability to metabolize. 
E)  the sea star's kidneys could not handle the change in ionic content presented by the freshwater.

Question 11

Through studies on the 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?

Accepted Answer

A)  Movement of potassium into the lumen of the Malpighian tubules is an energy- requiring process. 
B)  Sodium ions will follow potassium ions. 
C)  Potassium transport is a passive process. 
D)  Potassium moves out of the tubules at a faster rate than it moves into the lumen of the tubules. 
A)  Movement of potassium into the lumen of the Malpighian tubules is an energy- requiring process. 
B)  Sodium ions will follow potassium ions. 
C)  Potassium transport is a passive process. 
D)  Potassium moves out of the tubules at a faster rate than it moves into the lumen of the tubules.

Question 12

Insects maintain water and electrolyte balance through which anatomical structures?

Accepted Answer

A)  chloride cells 
B)  rectal gland 
C)  Malpighian tubules 
D)  kidneys 
A)  chloride cells 
B)  rectal gland 
C)  Malpighian tubules 
D)  kidneys

Question 13

Urine formation is involved in water and electrolyte balance in vertebrates. Which of the following statements is the most correct regarding urine formation?

Accepted Answer

A)  The formation of the pre- urine is selective. 
B)  Water is actively pumped across cell membranes to create osmotic gradients. 
C)  Reabsorption is highly selective so that only ions that are needed are reabsorbed. 
D)  The Malpighian tubules form the pre- urine. 
A)  The formation of the pre- urine is selective. 
B)  Water is actively pumped across cell membranes to create osmotic gradients. 
C)  Reabsorption is highly selective so that only ions that are needed are reabsorbed. 
D)  The Malpighian tubules form the pre- urine.

Question 14

Tissues of sharks 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. What can you infer about the movement of sodium and chloride in these animals?

Accepted Answer

A)  To maintain homeostasis of sodium and chloride levels, the shark must take up additional sodium and chloride from seawater. 
B)  Sharks conserve sodium and chloride, limiting excretion. 
C)  Sodium and chloride must be eliminated through the gills. 
D)  Sodium and chloride will diffuse through shark gills from seawater down their concentration gradient. 
A)  To maintain homeostasis of sodium and chloride levels, the shark must take up additional sodium and chloride from seawater. 
B)  Sharks conserve sodium and chloride, limiting excretion. 
C)  Sodium and chloride must be eliminated through the gills. 
D)  Sodium and chloride will diffuse through shark gills from seawater down their concentration gradient.

Question 15

The functional unit of the kidney is

Accepted Answer

A)  the ureters. 
B)  the loop of Henle. 
C)  the renal corpuscle. 
D)  the nephron. 
A)  the ureters. 
B)  the loop of Henle. 
C)  the renal corpuscle. 
D)  the nephron.

Question 16

Freshwater fish dilute ammonia and excrete it in a watery urine. Both freshwater and saltwater fish get rid of ammonia through diffusion across the gills. Humans convert ammonia to urea and excrete it in the urine. Birds convert ammonia to uric acid and excrete it. Why is it important for birds to get rid of ammonia?

Accepted Answer

A)  It is insoluble in water. 
B)  It is toxic. 
C)  Ammonia interferes with water loss. 
D)  It is used to synthesize nonessential amino acids. 
A)  It is insoluble in water. 
B)  It is toxic. 
C)  Ammonia interferes with water loss. 
D)  It is used to synthesize nonessential amino acids.

Question 17

What is the organ responsible for regulating water and electrolyte balance in terrestrial vertebrates?

Accepted Answer

A)  kidneys 
B)  chloride cells 
C)  Malpighian tubules 
D)  rectal glands 
A)  kidneys 
B)  chloride cells 
C)  Malpighian tubules 
D)  rectal glands

Question 18

Which of the following mechanisms contributes to osmoregulation in both marine and freshwater bony fish?

Accepted Answer

A)  gain of water through food 
B)  gain of salt through the gills via active transport 
C)  excretion of hyperosmotic urine 
D)  gain of water through the gills via osmosis 
E)  loss of salt through the gills via diffusion 
A)  gain of water through food 
B)  gain of salt through the gills via active transport 
C)  excretion of hyperosmotic urine 
D)  gain of water through the gills via osmosis 
E)  loss of salt through the gills via diffusion

Question 19

In flour beetles and desert locusts, how is water conserved?

Accepted Answer

A)  Water is transported into hindgut cells through endocytosis. 
B)  The pre- urine formed in the Malpighian tubules is hypertonic. 
C)  Sodium and chloride are actively transported out of pre- urine, and water follows, forming a hypertonic urine. 
D)  Urine that is formed is isotonic to hemolymph, but the muscle cells surrounding spiracles of these organisms are able to significantly limit water loss due to respiration. 
A)  Water is transported into hindgut cells through endocytosis. 
B)  The pre- urine formed in the Malpighian tubules is hypertonic. 
C)  Sodium and chloride are actively transported out of pre- urine, and water follows, forming a hypertonic urine. 
D)  Urine that is formed is isotonic to hemolymph, but the muscle cells surrounding spiracles of these organisms are able to significantly limit water loss due to respiration.

Question 20

Malpighian tubules form pre- urine, which is further processed by which of the following anatomical structures?

Accepted Answer

A)  hemolymph 
B)  rectal gland 
C)  chloride cells 
D)  hindgut 
A)  hemolymph 
B)  rectal gland 
C)  chloride cells 
D)  hindgut

Exam 40: Water and Electrolyte Balance in Animals

Table 40.1 -What role does Na+/K+- ATPase play in salt excretion by the shark rectal gland?

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?

Which of the following affects the osmolarity of a solution?

Which of the following is a function of antidiuretic hormone ADH)?

Terrestrial organisms lose water through evaporation. Why are desert locusts and flour beetles good organisms to use in studying mechanisms to regulate water loss?

Which of the following are soluble compounds that contribute to intracellular osmolarity in shark tissues?

The force driving simple diffusion is

What role do chloride cells play in osmoregulation of marine fish with bony skeletons?

Table 40.1 -The intercellular concentration of three electrolytes is compared with the concentration of these electrolytes in fluid eliminated from the shark rectal gland in Table 40.1. Based on the data, which of the following is a likely function of the rectal gland?

A necropsy postmortem analysis) of a marine sea star that died after it was mistakenly placed in freshwater would likely show that it died because

Through studies on the 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?

Insects maintain water and electrolyte balance through which anatomical structures?

Urine formation is involved in water and electrolyte balance in vertebrates. Which of the following statements is the most correct regarding urine formation?

Tissues of sharks 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. What can you infer about the movement of sodium and chloride in these animals?

The functional unit of the kidney is

What is the organ responsible for regulating water and electrolyte balance in terrestrial vertebrates?

Which of the following mechanisms contributes to osmoregulation in both marine and freshwater bony fish?

In flour beetles and desert locusts, how is water conserved?

Malpighian tubules form pre- urine, which is further processed by which of the following anatomical structures?

Biology and the Tree of Life

Water and Carbon: the Chemical Basis of Life

Protein Structure and Function

Nucleic Acids and the Rna World

An Introduction to Carbohydrates

Lipids, Membranes, and the First Cells

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Table 40.1 -What role does Na⁺/K⁺- ATPase play in salt excretion by the shark rectal gland?

Through studies on the 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?