Question 1

Freshwater flatworms and earthworms are similar in that their excretory systems reabsorb electrolytes and eliminate concentrated urine.

Accepted Answer

Freshwater flatworms use flame cells for excretion, which primarily remove excess water and small solutes, not producing concentrated urine. Earthworms have nephridia that filter fluid from the coelom, reabsorb useful substances, and excrete waste as dilute urine, not concentrated urine.

Question 2

In the vertebrate kidney, reabsorption and secretion take place in the renal tubules; after that, the filtrate enters the collecting ducts as _____.

Accepted Answer

The answer of In the vertebrate kidney, reabsorption and secretion...

Question 3

When proteins and nucleic acids are broken down, the toxic products are collectively called _____ waste.

Accepted Answer

The answer of When proteins and nucleic acids are broken...

Question 4

Most mammals excrete _____; most aquatic animals excrete _____; birds, insects, and many reptiles excrete _____.

Accepted Answer

Most mammals excrete urea, which is less toxic and requires less water than ammonia. Most aquatic animals excrete ammonia directly into the water. Birds, insects, and many reptiles excrete uric acid, which conserves water.

Question 5

Which of the following CORRECTLY lists the three forms of nitrogenous waste in order from least to most toxic?

Accepted Answer

Uric acid is the least toxic, followed by urea, and ammonia is the most toxic.

Question 6

Reabsorption is an important process in waste removal by excretory organs. Which of the following occur during reabsorption in vertebrate kidneys?

Accepted Answer

Reabsorption in vertebrate kidneys involves active transport, which requires energy (A), and water reenters the bloodstream through osmosis (B). Nitrogenous compounds are typically excreted, not reabsorbed, and not all electrolytes are removed from the filtrate.

Question 7

Which of the following is an advantage of producing very concentrated urine?

Accepted Answer

Producing very concentrated urine helps in minimizing water loss and reducing the need to drink, which is advantageous for animals living in drier environments. Therefore, all of the given choices are correct.

Question 8

What organ helps concentrate and secrete nitrogenous waste in insects?

Accepted Answer

Malpighian tubules are the organ system that help concentrate and secrete nitrogenous waste in insects. They are responsible for removing the waste products from the hemolymph (insect blood) and eventually excreting them as solid material through the rectum.

Question 9

A cockroach has a very "salty" meal. Which of the following would you expect to occur?

Accepted Answer

The answer of A cockroach has a very "salty" meal....

Question 10

When animals excrete nitrogenous waste, what form does it take?

Accepted Answer

Animals can excrete nitrogenous waste in different forms depending on their physiology and environment. Aquatic animals such as fish typically excrete ammonia, which is highly toxic but can be efficiently eliminated in water. Terrestrial animals, on the other hand, need to conserve water and therefore convert ammonia into less toxic but more water-soluble forms such as urea (mammals, most amphibians, sharks, some bony fish) or uric acid (birds, reptiles, insects). Therefore, all the choices are correct as animals can excrete nitrogenous waste in the form of ammonia, urea, or uric acid depending on their adaptations.

Question 11

Which of the following is a component of a vertebrate kidney?

Accepted Answer

Glomerulus, Bowman's capsule, renal tubules, and collecting ducts are all components of a vertebrate kidney. Malpighian tubules are found in invertebrates, such as insects.

Question 12

Nitrogenous wastes are produced through the breakdown of which of the following?

Accepted Answer

Nitrogenous wastes are produced through the breakdown of proteins during metabolism. Glucose, lipids, and carbohydrates do not contain nitrogen, so they do not produce nitrogenous waste.

Question 13

You discover a new type of marine organism that has the kidneys of a fish but no gills. Based on what you know about other aquatic organisms, the newly discovered organism is _____ compared to the surrounding water.

Accepted Answer

The answer of You discover a new type of marine...

Question 14

Ammonia is the most toxic of the three major forms of nitrogenous waste.

Accepted Answer

Ammonia is highly toxic to most organisms and can accumulate to harmful levels in aquatic environments, making it the most toxic of the three major nitrogenous wastes (ammonia, urea, and uric acid).

Question 15

Which process is responsible for creating MOST of an animal's nitrogenous waste?

Accepted Answer

Protein breakdown during metabolism produces the majority of an animal's nitrogenous waste. When proteins are metabolized, the nitrogen in them is converted to ammonia or urea, which are excreted as waste products. While nitrogen can also be obtained from food, the amount consumed is generally lower than that produced during protein metabolism. Respiration does not produce nitrogenous waste, and toxins in the environment may contribute to nitrogenous waste production but are not the primary source.

Question 16

In addition to eliminating toxic compounds, the three-step waste elimination process also allows multicellular organisms to regulate the amount of water and solutes in their bodies.

Accepted Answer

The three-step waste elimination process, including filtration, reabsorption, and secretion, also helps regulate the balance of water and solutes in an organism's body. This is achieved by selectively reabsorbing ions and water back into the body during filtration, and secreting excess ions and waste products out of the body.

Question 17

Excreting ammonia directly into the environment:

Accepted Answer

Excreting ammonia directly is energetically inexpensive because it does not require conversion to less toxic forms, but it requires high volumes of water to dilute its toxicity.

Question 18

Uric acid is:

Accepted Answer

Uric acid is the least toxic form of nitrogen waste, allowing organisms that excrete it, such as birds and reptiles, to conserve water. This is because it is less soluble in water and can be excreted as a paste or solid, minimizing water loss compared to more soluble forms of nitrogen waste like ammonia or urea.

Question 19

In the vertebrate kidney, blood filtration happens through the walls of special capillaries that form a tufted loop called a _____, which is surrounded by a capsule.

Accepted Answer

The answer of In the vertebrate kidney, blood filtration happens...

Question 20

Desert reptiles excrete nitrogenous waste in the form of uric acid, which allows them to reabsorb most of the water from their urine.

Accepted Answer

Desert reptiles have evolved to conserve water by excreting nitrogenous waste in the form of uric acid, which is less toxic than ammonia and requires less water to eliminate. Uric acid is also highly insoluble, which allows reptiles to reabsorb most of the water from their urine before excreting it. This adaptation is crucial for survival in arid environments where water is scarce.

Quiz 41: Animal Renal Systems: Water and Waste