Chapter 41 Questions

Question 1

Fat digestion yields fatty acids and glycerol. Protein digestion yields amino acids. Both digestive processes

a. occur inside cells in most animals.
b. add a water molecule to break bonds.
c. require a low pH resulting from HCl production.
d. consume ATP.

Answer 1

b. add a water molecule to break bonds.

Question 2

The mammalian trachea and esophagus both connect to the

a. pharynx.
b. stomach.
c. large intestine.
d. rectum.

Answer 2

a. pharynx.

Question 3

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

a. stomach—protein digestion
b. large intestine—bile production
c. small intestine—nutrient absorption
d. pancreas—enzyme production

Answer 3

b. large intestine—bile production

Question 4

Which of the following is not a major activity of the stomach?

a. storage
b. HCl production
c. nutrient absorption
d. enzyme secretion

Answer 4

c. nutrient absorption

Question 5

If you put the following events in the order they occur in the human digestive system, the third event in the series would be

a. Cells in gastric pits secrete protons.
b. Pepsin activates pepsinogen.
c. HCl activates pepsinogen.
d. Partially digested food enters the small intestine.

Answer 5

b. Pepsin activates pepsinogen.

Question 6

After surgical removal of the gallbladder, a person might need to limit his or her dietary intake of

a. starch.
b. protein.
c. sugar.
d. fat.

Answer 6

d. fat.

Question 7

If you were to jog 1 km a few hours after lunch, which stored fuel would you probably tap?

a. muscle proteins
b. muscle and liver glycogen
c. fat in the liver
d. fat in adipose tissue

Answer 7

b. muscle and liver glycogen

Question 8

Essential amino acids are _____.

a. all of the amino acids required to make proteins
b. those that cannot be made in the body
c. those that contain nitrogen
d. obtained only by eating plants
e. obtained only by eating animals

Answer 8

b. those that cannot be made in the body

Question 9

A complete digestive tract, or alimentary canal, differs from a gastrovascular cavity in that only the complete tract

a. permits extracellular digestion
b. has teeth and tentacles to help with ingestion
c. uses its surface area for nutrient absorption
d. has specialized compartments
e. allows elimination of undigested wastes

Answer 9

d. has specialized compartments

Question 10

In humans, the first opportunity for ingested food to undergo enzymatic hydrolysis is in the _____.

a. mouth
b. stomach
c. liver
d. small intestine
e. large intestine

Answer 10

a. mouth

Question 11

Hydrochloric acid in the stomach _____.

a. splits polypeptides into amino acids
b. splits fats into fatty acids and glycerol
c. activates pepsinogen into pepsin
d. initiates the development of stomach ulcers
e. inhibits the production of epithelial cells

Answer 11

c. activates pepsinogen into pepsin

Question 12

The bile salts function in fat digestion by _____.

a. hydrolyzing fat molecules to glycerol and fatty acids
b. separating individual fat molecules from each other
c. dissolving fats in water
d. dispersing big droplets of fats to small droplets
e. triggering the secretion of pancreatic lipase

Answer 12

d. dispersing big droplets of fats to small droplets

Question 13

A fatty acid absorbed into an intestinal cell _____.

a. is hydrolyzed to smaller fragments
b. enters a lacteal vessel as a carbohydrate
c. becomes part of a chylomicron
d. is bound to bile salts
e. exits the cell to directly enter the blood

Answer 13

c. becomes part of a chylomicron

Question 14

Glucagon, a pancreatic hormone, functions to _____.

a. stimulate hunger
b. inhibit activity in the small intestine
c. increase fat storage in fat cells
d. reduce glucose levels in the blood
e. stimulate the liver to release glucose

Answer 14

e. stimulate the liver to release glucose

Question 15

Increased appetite is the typical result of increased levels in the blood of _____.

a. leptin
b. PYY
c. ghrelin
d. insulin
e. secretin

Answer 15

c. ghrelin

Question 16

Increased glucose levels in blood, after a meal, trigger _____.

a. glucagon release from the pancreas
b. insulin release from the pancreas
c. secretin release from the duodenum
d. cholecystokinin release from the pancreas
e. activation of amylase in the blood

Answer 16

b. insulin release from the pancreas

Question 17

In which of the following structures does absorption of water, vitamin K, and salt occur?

a. large intestine
b. small intestine
c. liver
d. stomach
e. pancreas

Answer 17

a. large intestine

Question 18

Which of the following organisms is most likely to have an extremely large cecum?

a. carnivore
b. ruminant herbivore
c. nonruminant herbivore
d. insectivore

Answer 18

c. nonruminant herbivore

Question 19

What is a lacteal?

a. a vessel within each villus
b. part of the vertebrate immune system
c. a type of liver sinusoid
d. a globule containing phospholipid, cholesterol, and protein

Answer 19

a. a vessel within each villus

Question 20

Ninety-five percent of the bacterial DNA sequences obtained from stomachs of individuals infected with the bacterium Helicobacter pylori were found to be H. pylori (phylum Proteobacteria). A conclusion that may be drawn from this finding is _____.

a. Actinobacteria, Firmicutes, Bacteroidetes, and Fusobacteria do not cause ulcers
b. Actinobacteria, Firmicutes, Bacteroidetes, and Fusobacteria are bacterial symbionts required for human health
c. H. pylori outcompetes compete resident bacterial species in infected individuals
d. Uninfected individuals have less resident Fusobacteria than infected

Answer 20

c. H. pylori outcompetes compete resident bacterial species in infected individuals

Question 21

The primary reason the hepatic portal vein delivers blood containing the products of digestion directly to the liver is in order to _____.

a. recover excess water and ions
b. store glucose as glycogen
c. detoxify foreign molecules and metabolic wastes
d. allow toxic substances to circulate broadly
e. conduct blood from the gastrointestinal tract to the heart

Answer 21

c. detoxify foreign molecules and metabolic wastes

Question 22

A simple change contributed to the improvement of human health by reducing the risk of neural tube defects. This change was the _____.

a. iodination of table salt
b. consumption of massive doses of vitamin supplements
c. recommendation that the shift from breast milk to solid foods be delayed
d. supplementation of soils with phosphorus
e. addition of folic acid to grain products

Answer 22

e. addition of folic acid to grain products

Question 23

Which of the following cell types is incorrectly matched with its function?

a. parietal—pumps sodium ions into the stomach lumen
b. chief—releases pepsinogen into the stomach lumen
c. epithelial—within villus, contains projections that face the intestinal lumen
d. alpha—makes glucagon
e. beta—makes insulin

Answer 23

a. parietal—pumps sodium ions into the stomach lumen

Question 24

Which of the following statements correctly describes non-insulin-dependent (type 2) diabetes?

a. It is body weight and exercise independent.
b. It usually appears during childhood.
c. Immune cells destroy pancreatic insulin-producing islets.
d. Stem cell research is under investigation for a cure.
e. Blood glucose levels may be improved with regular exercise and a healthy diet.

Answer 24

e. Blood glucose levels may be improved with regular exercise and a healthy diet.

Question 25

Which of these statements about the role of the human microbiome in health and disease is not correct?

a. Microbiome differences may aid in the development of therapies for certain diseases.
b. Microbiome changes may play a role in some abnormal conditions or disease states.
c. Brain function or mood may be affected by digestive system microorganisms.
d. Human mutualistic colon bacteria contain hydrolytic enzymes for digesting cellulose to simple sugars.
e. Intestinal development and immune function are regulated by intestinal bacteria.

Answer 25

d. Human mutualistic colon bacteria contain hydrolytic enzymes for digesting cellulose to simple sugars.

Question 26

Which of the following organs or structures is not part of the large intestine?

a. cecum
b. colon
c. appendix
d. jejunum
e. rectum

Answer 26

d. jejunum

Question 27

The following table shows the contents of a multivitamin supplement and its percentage of recommended daily values (%DV).
Table.
The most likely reason that some of the vitamins and minerals in this supplement are found at less than 100% is that ___.
a. it is dangerous to overdose on fat-soluble vitamins such as A and K
b. these vitamins and minerals are too large in size to reach 100%
c. it is too easy to overdose on minrals such as phosphorous and calcium
d. it would be chemically impossible to add more

Answer 27

a. it is dangerous to overdose on fat-soluble vitamins such as A and K

Question 28

Animals that migrate great distances would obtain the greatest energetic benefit of storing chemical energy as ___.

a. proteins
b. carbohydrates
c. minerals
d. fats

Answer 28

d. fats

Question 29

Lysine is an essential amino acid for animals. If an animal did not consume lysine in its diet, you might expect that the animal ___.

a. could not effectively make many necessary proteins
b. was a carnivore
c. would make lysine from other amino acids
d. would be very healthy

Answer 29

a. could not effectively make many necessary proteins

Question 30

Three groups of cyclists consumed three different types of diets: high-carbohydrate; a diet mixed in carbohydrates, fat, and protein; or a diet higher in protein and fat. The average time each group could spend cycling over a six-hour period is shown in the accompanying graph. What conclusion from the data would help an athlete or trainer improve performance?
Figure
a. An early 50 percent drop in blood glucose is associated with improved endurance.
b. Diet is not at all related to endurance.
c. Maintaining elevated blood sugar improves performance.
d. Endurance is entirely related to diet.

Answer 30

c. Maintaining elevated blood sugar improves performance.

Question 31

Ticks are parasites that obtain nutrients by ingesting blood from a host animal. Ticks would be classified as ___.

a. substrate feeders
b. fluid feeders
c. filter feeders
d. bulk feeder

Answer 31

b. fluid feeders

Question 32

Because the foods eaten by animals are often composed largely of macromolecules, animals need to have mechanisms for ___.

a. regurgitation
b. demineralization
c. dehydration synthesis
d. enzymatic hydrolysis

Answer 32

d. enzymatic hydrolysis

Question 33

Fat digestion yields fatty acids and glycerol, whereas protein digestion yields amino acids; both digestive processes ___.

a. use water molecules when breaking bonds (hydrolysis)
b. require adenosine triphosphate (ATP) as an energy source
c. require the presence of hydrochloric acid to lower the pH
d. are catalyzed by the same enzyme

Answer 33

a. use water molecules when breaking bonds (hydrolysis)

Question 34

Mechanical digestion, the process of breaking down large chunks of food into smaller pieces, is important because smaller pieces of food ___.

a. are more easily stored in the stomach than are larger pieces of food
b. do not taste as good as larger pieces of food
c. have more surface area for chemical digestion than do larger pieces of food
d. are easier to excrete than are larger pieces of food

Answer 34

c. have more surface area for chemical digestion than do larger pieces of food

Question 35

Stomach cells are moderately well adapted to the acidity and protein-digesting activities in the stomach by having ___.

a. a high level of secretion of enzymes by chief cells
b. a thick, mucous secretion and active mitosis of epithelial cells
c. a cell wall impermeable to acid
d. a sufficient colony of H. pylori

Answer 35

b. a thick, mucous secretion and active mitosis of epithelial cells

Question 36

Upon activation by stomach acidity, the secretions of the parietal cells ___.

a. initiate the chemical digestion of protein in the stomach
b. initiate the chemical digestion of lipids in the stomach
c. delay digestion until the food arrives in the small intestine
d. initiate the mechanical digestion of lipids in the stomach

Answer 36

a. initiate the chemical digestion of protein in the stomach

Question 37

Over-the-counter medications for acid reflux or heartburn block the production of stomach acid. Which of the following cells are directly affected by this medication?

a. parietal cells
b. goblet cells
c. smooth muscle cells
d. chief cells

Answer 37

a. parietal cells

Question 38

Cattle are able to survive on a diet consisting almost entirely of plant material because cattle ____.

a. are autotrophic
b. manufacture all fifteen amino acids out of sugars in the liver
c. re-ingest their feces
d. have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs

Answer 38

d. have cellulose-digesting, symbiotic microorganisms in chambers of their stomachs

Question 39

A zoologist analyzes the jawbones of an extinct mammal and concludes that it was an herbivore. The zoologist most likely came to this conclusion based upon the ___.

a. angle of the teeth in the mouth
b. size of the mouth opening
c. shape of the teeth
d. position of muscle attachment sites

Answer 39

c. shape of the teeth

Question 40

If you found a vertebrate skull in the woods and the teeth were sharp and scissor-like, what type of food would you expect this animal to eat?

a. flesh of another animal
b. nectar
c. blood
d. grass

Answer 40

a. flesh of another animal

Question 41

What benefit is gained by intestinal bacteria living in a mutualistic relationship with an animal?

a. The bacteria can avoid the animal’s immune system.
b. The bacteria are provided with a regular source of nutrients.
c. The bacteria can easily infect the animal’s intestinal cells.
d. Temperature is always regulated.

Answer 41

b. The bacteria are provided with a regular source of nutrients.

Question 42

When used appropriately, antibiotic treatment can effectively reduce bacteria populations and help fight infections. However, antibiotic treatments can have unintended effects. What is one concern when using antibiotics?

a. Antibiotics also damage animal cells, so they can be more harmful than a bacterial infection.
b. Antibiotics may also kill the beneficial bacteria of the microbiome, thereby disrupting digestive health.
c. Antibiotics cause viruses to become more effective at infecting cells.
d. Each antibiotic is only effective against one type of bacteria, so effects on infection are limited.

Answer 42

b. Antibiotics may also kill the beneficial bacteria of the microbiome, thereby disrupting digestive health.

Question 43

In a healthy person, after a carbohydrate-rich meal, the production of ___ will increase, causing the uptake of ___ from the blood into liver cells.

a. glucagon; protein
b. glucagon; glucose
c. insulin; glucose
d. insulin; glucagon

Answer 43

c. insulin; glucose

Question 44

If there is a strong genetic link for type II diabetes mellitus in your family, how might you minimize your risk of developing the disorder?

a. maintain a healthy weight, eat a balanced diet, and exercise
b. monitor your blood glucose levels daily
c. eat complex carbohydrates like starch instead of sweets
d. take oral insulin daily

Answer 44

a. maintain a healthy weight, eat a balanced diet, and exercise

Question 45

Choose the list that presents the four stages of food processing in the order in which they naturally occur.

a. ingestion → digestion → absorption → elimination
b. ingestion → absorption → elimination → digestion
c. ingestion → digestion → elimination → absorption
d. digestion → ingestion → absorption → elimination
e. absorption → digestion → ingestion → elimination

Answer 45

a. ingestion → digestion → absorption → elimination

Question 46

The gastrovascular cavity differs from the alimentary canal in that only the gastrovascular cavity _____.

a. has only a single opening
b. functions in digestion but not absorption
c. absorbs food molecules but does not produce hydrolytic enzymes
d. stores food but does not digest it
e. is capable of extracellular digestion

Answer 46

a. has only a single opening

Question 47

Choose the correct anatomical sequence that presents the order in which food in the digestive system passes through.

a. esophagus → stomach → pharynx → small intestine
b. pharynx → stomach → esophagus → small intestine
c. pharynx → small intestine → large intestine → stomach
d. esophagus → pharynx → stomach → small intestine
e. pharynx → esophagus → stomach → small intestine → large intestine

Answer 47

e. pharynx → esophagus → stomach → small intestine → large intestine

Question 48

For ingested foods, the first opportunity for enzymatic digestion occurs in the _____.

a. stomach
b. large intestine
c. pancreas
d. small intestine
e. mouth

Answer 48

e. mouth

Question 49

The lower esophageal sphincter surrounds the upper opening into the stomach. If this sphincter failed to properly constrict, there might be a problem with _____.

a. too rapid emptying from the stomach into the small intestine
b. the movement of swallowed food into the trachea rather than into the esophagus
c. regurgitation of acidic stomach contents into the esophagus, commonly called “heartburn”
d. too rapid emptying of the small intestine into the large intestine
e. the control of defecation

Answer 49

c. regurgitation of acidic stomach contents into the esophagus, commonly called “heartburn”

Question 50

Different types of food are eaten by various groups of animals, but it is usually true that _____.

a. the teeth of herbivores tend to be sharper than the teeth of carnivores
b. animals typically produce enzymes that hydrolyze cellulose
c. the intestines of carnivores tend to be longer than the intestines of herbivores of similar overall body size
d. many carnivorous vertebrates house large populations of symbiotic bacteria and protists in special fermentation chambers in their stomachs
e. cellulose digestion in ruminant mammals occurs before the ingested foods reach the small intestine

Answer 50

e. cellulose digestion in ruminant mammals occurs before the ingested foods reach the small intestine

Question 51

Among humans, increased interest in food intake normally occurs _____.

a. via chemical signals related to the amount of protein stores in the liver
b. via chemical signals related to the amount of glucose stored in the liver and muscle cells
c. only after the production of glucose in the liver can no longer meet metabolic needs
d. when fewer calories are taken in than are expended, but only after the body depletes its reserves of fat in the liver
e. via chemical signals released when the stomach is empty

Answer 51

e. via chemical signals released when the stomach is empty

Question 52

Consider the interior surface of the human stomach and its secretions, shown in the figure. Why doesn’t gastric juice, composed of hydrochloric acid and a protease called pepsin, digest the cells that line the stomach?

a. Chief cells release pepsin in an inactive form. HCl in the stomach converts pepsin to an active form of the enzyme called pepsinogen by clipping off a small portion of the molecule to expose its active site.
b. Digestion doesn’t begin until the small intestine.
c. The stomach lining secretes mucus, a mixture of glycoproteins, cells, salts, and water.

Answer 52

c. The stomach lining secretes mucus, a mixture of glycoproteins, cells, salts, and water.