Deck 42: Water and Electrolyte Balance in Animals

Question 1

Which of the following affects the osmolarity of a solution?

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

Answer 1

D

Question 2

Which of the following most accurately describes selective permeability?

A)Molecules below a certain molecular weight cross the membrane easily.
B)Lipid-soluble molecules pass through the membrane.
C)There must be a concentration gradient for molecules to pass through the membrane.
D)The ability of a molecule to pass through a membrane depends on transport and channel proteins present in the membrane.

Answer 2

D

Question 3

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?

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

Answer 3

A

Question 4

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

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

Question 5

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

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

Question 6

Marine vertebrates live in a(n)________ environment.

A)isotonic
B)hypotonic
C)hypertonic
D)osmotonic

Question 7

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?

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

Question 8

What is the function of the shark rectal gland?

A)It is involved in osmoregulation.
B)It is responsible for excretion of undigested residue.
C)It secretes a hypotonic solution.
D)It concentrates electrolytes necessary for homeostasis in a hypertonic environment.

Question 9

Freshwater fish live in a hypotonic environment.To maintain homeostasis in this environment,they 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.

Question 10

The force driving simple diffusion is

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

Question 11

Which of the following is an example of osmoregulation?

A)two solutions that are isotonic
B)the contractile vacuole of a Paramecium
C)type 2 diabetes mellitus
D)all of the above

Question 12

Table 42.1

Refer to Table 42.1: Because the shark rectal gland functions only when ATP molecules are present,what can you infer about the movement of Na⁺,K⁺,and Cl⁻?

A)Movement of these ions from circulation into the rectal gland is an active process.
B)Movement of these ions takes place from a region of higher concentration to a region of lower concentration.
C)These ions move into the rectal gland with their osmotic gradient.
D)The rectal gland is unable to concentrate these ions.

Question 13

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?

A)The rectal gland functions in the ocean water,and chloride cells function in freshwater.
B)Different gill cells are involved in osmoregulation in freshwater than in salt water.
C)Salmon surface to breathe oxygen,so there is no need for more than one mechanism of osmoregulation.
D)Their metabolism changes in salt water to degrade electrolytes.

Question 14

Freshwater fish reside in hypotonic environments.They do not drink water,and they excrete large volumes of hypotonic urine in an effort to osmoregulate.How do they obtain an adequate supply of electrolytes?

A)The rectal gland is specialized to produce the dilute (hypotonic urine)and conserve ions.
B)Chloride cells transport additional electrolytes into the circulation of these organisms.
C)Gill lamellae take up additional electrolytes from freshwater.
D)There is an increase in Na⁺/K⁺-ATPase activity across the basolateral membrane.

Question 15

Paramecia live in pond water (a hypotonic environment).They have a structural feature,a contractile vacuole,that enables them to osmoregulate.If you observed paramecia in the following solutions,at which sucrose concentration 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

Question 16

Gas exchange in insects takes place across the epithelium of the tracheae (a system of tubes).The tracheal system connects to the outside air by openings called spiracles.Muscles just inside each spiracle can control the opening to minimize water loss.What would happen if the muscles inside each spiracle were unable to function?

A)The insect would be unable to eliminate carbon dioxide.
B)The spiracles would lock open.
C)Respiration in the insect would function normally.
D)Paralysis would result.

Question 17

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

A)They have a relatively large surface area/volume relationship.
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 stoma that regulate water loss.

Question 18

Table 42.1

The intercellular concentration of three electrolytes is compared with the concentration of these electrolytes in fluid eliminated from the shark rectal gland in Table 42.1.Based on the data,which of the following is a likely function of the rectal gland?

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

Question 19

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

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

Question 20

Which of the following is an example of equilibrium?

A)A substance moves into and out of a cell at the same rate.
B)A concentration gradient drives the movement of a substance into a cell.
C)ATP powers movement of a substance into a cell against its concentration gradient.
D)An electrochemical gradient drives the movement of a substance into a cell.

Question 21

How does ion composition of pre-urine differ from hemolymph?

A)Pre-urine is significantly higher in osmolarity (especially with respect to Na⁺ and K⁺).
B)Hemolymph is higher in osmolarity,conserving its Cl⁻.
C)Pre-urine is similar to hemolymph in ion composition.
D)The protein pumps and channels of the Malpighian tubules concentrate Cl⁻ in the pre-urine.

Question 22

The products of filtration in the renal corpuscle enter the renal tubule through which of the following structures?

A)the proximal convoluted tubule
B)the loop of Henle
C)the collecting duct
D)Bowman's capsule

Question 23

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?

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

Question 24

Water loss from insect surface is minimal due to which of the following structures?

A)chitin and the cuticle
B)tracheae and spiracles
C)a proteinaceous epidermis
D)a small surface area/volume relationship

Question 25

For filtration to take place through the fenestrated capillaries of the renal corpuscle,

A)concentration of ions must be greater in the capillaries (the glomerulus)than in the renal tubule.
B)there must be a greater pressure inside the glomerulus than in the renal tubules.
C)there must be a larger concentration of proteins in the renal tubule than in the glomerulus.
D)there must be more than one capillary bed in the renal corpuscle.

Question 26

Figure 42.1
Where does filtration take place in the figure above?

Question 27

On a very hot,dry day,you lose ________ through the skin.

A)water and electrolytes
B)water only
C)heat only
D)electrolytes only

Question 28

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

A)The pre-urine formed in the Malpighian tubules is hypertonic.
B)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.
C)Water is transported into hindgut cells through endocytosis.
D)Sodium and chloride are actively transported out of pre-urine,and water follows,forming a hypertonic urine.

Question 29

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

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

Question 30

Insects maintain water and electrolyte balance through which anatomical structures?

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

Question 31

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?

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.

Question 32

There are microvilli on the luminal (apical)surface of the epithelium that lines the lumen of the proximal tubule.Microvilli are structural features designed to

A)maximize surface area available to pump ions into the renal tubule.
B)maximize surface area available for reabsorption of solutes from the renal tubule.
C)accommodate membrane proteins involved in active transport of substances into the rental tubule.
D)provide adequate space to house membrane proteins involved in active transport of solutes out of the renal tubule.

Question 33

Reabsorption of water in the hindgut of insects is controlled by which of the following?

A)osmotic gradients created by ion pumps
B)selective absorptive processes that take place in the Malpighian tubules
C)ion concentration of hemolymph
D)osmoregulators in the rectal gland

Question 34

Proper functioning of body cells and processes requires solute concentrations to be maintained within a narrow range.Which of the following solutes would be absorbed by the proximal tubule of the kidney nephron?

A)triglyceride
B)urea
C)sodium
D)carbon dioxide

Question 35

The filtrate formed in the renal corpuscle is analogous to the ________ formed in Malpighian tubules.

A)hemolymph
B)pre-urine
C)uric acid
D)the hypertonic solution

Question 36

The loop of Henle dips into the renal cortex.This is an important feature of osmregulation 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.

Question 37

A potassium ion gradient is set up in the 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.

Question 38

Different habitats pose certain challenges to animal survival.For instance,terrestrial insects must maintain water balance by minimizing evaporation.How do insects minimize water loss?

A)Keep the spiracles open.
B)Eat more plant material that is high in water content.
C)Have a cuticle covered by a waxy hydrophobic layer.
D)Excrete nitrogenous waste as urea.

Question 39

The functional unit of the kidney is

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

Question 40

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

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

Question 41

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

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