04 Digestion & Excretion

Question 1

Some nutrients are consideredessential”in the diets of certain animals because

only those animals use the nutrients.
they are subunits of important polymers.
they cannot be manufactured by the organism.
they are necessary coenzymes.
only some foods contain them.

Answer 1

they cannot be manufactured by the organism.

Question 2

To leave the digestive tract, a substance must cross a cell membrane. During which stage of food processing does this take place?

ingestion
digestion
hydrolysis
absorption
elimination

Answer 2

absorption

Question 3

In which group of animals would you expect to find a relatively long cecum?

carnivores
herbivores
autotrophs
heterotrophs
omnivores

Answer 3

herbivores

Question 4

Why are cattle able to survive on a diet consisting almost entirely of plant material?

A) They are autotrophic.
B) Cattle, like the rabbit, reingest their feces.
C) They manufacture all 15 amino acids out of sugars in the liver.
D) Cattle saliva has enzymes capable of digesting cellulose.
E) They have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs

Answer 4

E) They have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs

Question 5

Which of the following organs is incorrectly paired with its function?

Stomach → protein digestion
oral cavity → starch digestion
large intestine → bile production
small intestine → nutrient absorption
Pancreas → enzyme production

Answer 5

large intestine → bile production

Question 6

A marine sea star was mistakenly placed in freshwater and it died. What is the most likely explanation for its death?

A) The sea star was stressed and needed more time to acclimate to new conditions.
B) The sea star is hyperosmotic to the freshwater, and it could not osmoregulate.
C) The osmoregulatory system of the sea star could not handle the change in ionic content presented by the freshwater.
D) The contractile vacuoles used to regulate water content ruptured in the freshwater.
E) The cells of the sea star dehydrated and lost the ability to metabolize

Answer 6

C) The osmoregulatory system of the sea star could not handle the change in ionic content presented by the freshwater.

Question 7

Unlike most bony fishes, sharks maintain body fluids that are isoosmotic to sea water. They are therefore considered by many to be osmoconformers because of the unusual way they maintain homeostasis. They osmoregulate by

A) using their gills and kidneys to rid themselves of sea salts.
B) monitoring dehydration at the cellular level with special gated aquaporins.
C) tolerating high urea concentrations that balance internal salt concentrations to sea water osmolarity.
D) synthesizing trimethylamine oxide, a chemical that speeds salt removal from cells.
E) possessing a special adaptation that allows their cells to operate at an unusually high salt concentration

Answer 7

C) tolerating high urea concentrations that balance internal salt concentrations to sea water osmolarity.

Question 8

Where and from what compound(s) is urea produced?

liver from NH3 and CO2
liver from glycogen
kidneys from glucose
kidneys from glycerol and fatty acids
bladder from uric acid and H2O

Answer 8

liver from NH3 and CO2

Question 9

What is the main nitrogenous waste excreted by birds?

ammonia
nitrate
nitrite
urea
uric acid

Answer 9

uric acid

Question 10

Materials are returned to the blood from the filtrate by which of the following processes?

filtration
ultrafiltration
selective reabsorption
secretion
active transport

Answer 10

selective reabsorption

Question 11

Which group possess excretory organs known as Malpighian tubules?

earthworms
flatworms
insects
jellyfish
sea stars

Answer 11

insects