Deck 51: Nutrition, Digestion, and Absorption

Question 1

Chylomicrons are like the tiny micelles of dietary fat in the lumen of the small intestine in that both

A) are coated with bile.
B) are lipid soluble.
C) travel through the lymphatic system.
D) contain triglycerides.
E) are coated with lipoproteins.

Answer 1

D

Question 2

Which statement about nutrient absorption by the intestinal mucosal cells is true?

A) Carbohydrates are absorbed as disaccharides.
B) Fats are absorbed as fatty acids and monoglycerides.
C) Amino acids move across the plasma membrane only by diffusion.
D) Bile transports fats across the plasma membrane.
E) Most nutrients are absorbed in the duodenum.

Answer 2

B

Question 3

The major form of stored energy in animal bodies is _______, because it _______.

A) protein; is a long-term energy storage form
B) glycogen; breaks down into readily usable carbohydrates
C) glycogen; is lightweight
D) fat; has the highest energy content per gram
E) fat; is readily stored and dissolved in water

Answer 3

D

Question 4

Most animals digest dietary proteins into their constituent amino acids and then synthesize new proteins because

A) macromolecules like proteins cannot be readily transported through plasma membranes.
B) protein structure and function are highly species-specific.
C) foreign proteins are considered invaders and are attacked by the immune system.
D) All of the above
E) None of the above

Question 5

The digestive enzymes of the small intestine

A) do not function best at a low pH.
B) are produced and released in response to circulating secretin.
C) are produced and released under neural control.
D) are all secreted by the pancreas.
E) are all activated by an acidic environment.

Question 6

Which statement about vitamins is true?

A) They are essential inorganic nutrients.
B) They are required in larger amounts than are essential amino acids.
C) Many serve as coenzymes.
D) Vitamin D can be acquired only by eating meat or dairy foods.
E) When vitamin C is eaten in large quantities, the excess is stored in fat for later use.

Question 7

Which of the following statements about undernourishment is false?

A) One-sixth of the world's population is undernourished.
B) Several weeks of fasting are required to deplete glycogen reserves.
C) Self-imposed starvation is called anorexia nervosa.
D) The loss of blood proteins during starvation leads to edema.
E) During starvation, fat reserves are exhausted before the metabolism of body protein is accelerated.

Question 8

Microbial fermentation in the gut of a cow

A) produces fatty acids as a major nutrient for the cow.
B) occurs in specialized regions of the small intestine.
C) occurs in the cecum, from which food is regurgitated, chewed again, and swallowed into the true stomach.
D) produces methane as a major nutrient.
E) is possible because the stomach wall does not secrete hydrochloric acid.

Question 9

Organisms that derive their energy and molecular nutrients from other organisms are called

A) autotrophs.
B) herbivores.
C) heterotrophs.
D) photosynthetic.
E) protists.

Question 10

Which statement about essential amino acids is true?

A) They are not found in vegetarian diets.
B) They are stored by the body until they are needed.
C) Without them, one is undernourished.
D) All animals require the same ones.
E) Humans can acquire all of theirs by eating milk, eggs, and meat.

Question 11

Which of the following is stimulated by cholecystokinin?

A) Stomach motility
B) Release of bile
C) Secretion of hydrochloric acid
D) Secretion of bicarbonate ions
E) Secretion of mucus

Question 12

During the postabsorptive state,

A) glucose is the major metabolic fuel.
B) glucagon stimulates the liver to produce glycogen.
C) insulin facilitates the uptake of glucose by brain cells.
D) fatty acids constitute the major metabolic fuel.
E) liver functions slow down because of low insulin levels.

Question 13

The energy content of food is described in terms of calories because

A) the amount of energy in food depends on the temperature.
B) food heats up as it is being digested.
C) the energy in food ultimately becomes heat.
D) heat is the main product of digestion.
E) heat is the main product of respiration.

Question 14

The nutritional disease kwashiorkor results from a(n)

A) protein deficiency.
B) vitamin deficiency.
C) calorie deficiency.
D) overdose of fat-soluble vitamins.
E) overdose of thyroxine.

Question 15

Which of the following statements about energy storage is true?

A) Carbohydrates are stored in the liver and in muscle as glucose.
B) Fat is not an important form of stored energy.
C) Fat has the lowest energy content per gram.
D) Protein is the most important energy storage component.
E) The total glycogen stores are usually not more than a day's energy requirements.

Question 16

During the absorptive state,

A) breakdown of glycogen supplies glucose to the blood.
B) glucagon secretion is high.
C) the number of circulating lipoproteins is low.
D) glucose is the major metabolic fuel.
E) the synthesis of fats and glycogen in muscle is inhibited.

Question 17

Which of the following represents the order in which stored fuels are utilized in periods of starvation?

A) Fats, glycogen, proteins
B) Glycogen, proteins, fats
C) Proteins, fats, glycogen
D) Fats, proteins, glycogen
E) Glycogen, fats, proteins

Question 18

Compared to carnivores, herbivores require _______ essential amino acids and consequently are less likely to suffer from _______.

A) fewer; undernourishment
B) fewer; malnourishment
C) more; undernourishment
D) more; malnourishment
E) more; overnourishment

Question 19

Most of the metabolic energy needed by a bird for a long-distance migratory flight is stored as

A) glycogen.
B) fat.
C) protein.
D) carbohydrates.
E) ATP.

Question 20

Certain amino acids are called essential amino acids because they

A) are required for making protein.
B) cannot be made from other amino acids and must be obtained from food.
C) are universally needed by all animals.
D) are essential as an energy source.
E) are required for making nucleic acids.

Question 21

A strictly vegetarian diet with no vitamin B₁₂ supplements can lead to

A) beriberi.
B) pellagra.
C) pernicious anemia.
D) scurvy.
E) night blindness.

Question 22

Vitamin D is obtained by different people in various ways. For example,

A) dark-skinned people of high latitudes, such as the Inuit, obtain it from sunlight.
B) dark-skinned people of low latitudes obtain it from tropical sunlight.
C) some people obtain it from protein molecules that absorb sunlight.
D) some people obtain it from water-soluble components of foods.
E) light-skinned people of middle latitudes obtain it from drinking water.

Question 23

People living in impoverished regions, as well as people with alcohol addiction, frequently have a niacin deficiency called

A) beriberi.
B) kwashiorkor.
C) pellagra.
D) scurvy.
E) rickets.

Question 24

Which of the following statements about the essential amino acids is false?

A) Most animals have some essential amino acids.
B) Ingesting a surplus of one essential amino acid cannot compensate for a shortage of another.
C) Some foods, such as legumes, supply all eight of the essential amino acids in humans.
D) Acetyl groups can be combined with amino groups to produce many of the nonessential amino acids.
E) Like amino acids, some fatty acids are essential.

Question 25

The nutritional deficiency disease beriberi is caused by an inadequate supply of the water-soluble vitamin

A) B₁ (thiamin).
B) B₂ (riboflavin).
C) B₁₂ (cobalamin).
D) folic acid.
E) C (ascorbic acid).

Question 26

The nutritional deficiency disease rickets is caused by an inadequate supply of the fat-soluble vitamin

A) A (retinol).
B) D (calciferol).
C) E (tocopherol).
D) K (menadione).
E) biotin.

Question 27

The nutritional deficiency disease simple goiter is caused by inadequate supply of the micronutrient

A) fluoride.
B) iodine.
C) chromium.
D) zinc.
E) copper.

Question 28

Which of the following diseases is not due to a vitamin deficiency?

A) Pellagra
B) Rickets
C) Goiter
D) Pernicious anemia
E) Beriberi

Question 29

Primates should eat citrus fruit to prevent scurvy, which is due to a deficiency of

A) niacin.
B) thiamin.
C) calciferol.
D) ascorbic acid.
E) biotin.

Question 30

Which of the following statements about vitamins is false?

A) Vitamins, like essential amino acids and fatty acids, are organic molecules.
B) Most vertebrates require the same vitamins.
C) Vitamins function mostly as, or as parts of, coenzymes.
D) Vitamins are required only in very small amounts.
E) Humans require more water-soluble vitamins than fat-soluble vitamins.

Question 31

A fundamental difference between saprobes and detritivores is that

A) saprobes have long snouts that allow them access to food that is unavailable to detritivores.
B) only saprobes absorb nutrients from dead organisms.
C) detritivores are primarily bacteria.
D) only detritivores seek out dead organic items and eat them.
E) Both b and d

Question 32

A mammal with a diet of grain and leaves would be expected to have which kind of teeth?

A) Prominent canine teeth and small molars
B) Prominent molars and small canines
C) Prominent molars and small premolars
D) A balanced set of incisors, molars, and canines
E) Prominent canine teeth and small incisors

Question 33

Which of the following does not represent a carnivorous feeding adaptation?

A) A spiderweb
B) Rattlesnake venom
C) Bat echolocation
D) An elephant's trunk
E) A jellyfish tentacle

Question 34

Vitamins are essential nutrients for cells because they _______ and cannot be synthesized by the animal itself.

A) are used as an energy source
B) are used to digest foods
C) function as coenzymes
D) Both a and b
E) All of the above

Question 35

Nematocysts are an adaptation used by _______ to inject toxin into a victim.

A) jellyfish
B) spiders
C) snakes
D) short-tailed shrews
E) pufferfish

Question 36

Which of the following teeth are less prominent in animals with a diet consisting mainly of plants?

A) Incisors
B) Canines
C) Premolars
D) Molars
E) Cheek teeth

Question 37

The root of a typical tooth contains _______ and _______, but not _______.

A) enamel; cement; a pulp cavity
B) enamel; a pulp cavity; dentine
C) dentine; a pulp cavity; enamel
D) dentine; enamel; a pulp cavity
E) cement; dentine; a pulp cavity

Question 38

Which of the following statements about vitamin C is false?

A) It is necessary for wound healing.
B) It is obtained from fresh greens and fruit in the diet.
C) It is an essential vitamin for humans.
D) It is a fat-soluble vitamin.
E) An excess of vitamin C is excreted.

Question 39

_______ ingest both plant and animal food and process their food through _______ digestion.

A) Predators; intracellular
B) Omnivores; intracellular
C) Carnivores; intracellular
D) Herbivores; extracellular
E) Omnivores; extracellular

Question 40

A filter feeder acquires food items by

A) restraining prey with poison.
B) restraining prey by means of claws and jaws.
C) ingesting mud and extracting particles.
D) filtering food substances from blood.
E) extracting particles suspended in water.

Question 41

Pepsinogen is converted into pepsin by

A) low pH.
B) chyme.
C) enterokinase.
D) trypsinogen.
E) amylase from the salivary glands.

Question 42

Movement of food from the stomach into the esophagus is normally prevented by

A) peristalsis.
B) reverse peristalsis.
C) the pyloric sphincter.
D) a sphincter.
E) the pharynx.

Question 43

For most animals, absorption of nutrients occurs

A) intracellularly.
B) in the gastrovascular cavity.
C) in the coelomic body cavity.
D) in the midgut.
E) in the crop.

Question 44

The sweetness that you taste if you keep chewing a piece of bread is due the action of the enzyme

A) maltase.
B) sucrase.
C) lactase.
D) amylase.
E) pepsin.

Question 45

The inactive form of stomach enzymes is activated by

A) enterokinase.
B) ATP.
C) low pH.
D) the appropriate substrate molecule.
E) the presence of water.

Question 46

Which layer of the vertebrate gut shows adaptations for increasing absorptive surface area?

A) Lumen
B) Mucosa
C) Submucosa
D) Serosa
E) Peritoneum

Question 47

Which of the following is not caused by the HCl secreted in the stomach?

A) Activation of the principal zymogen of the stomach
B) Proper pH for the digestive enzyme of the stomach
C) Breakdown of ingested tissues
D) Formation of chylomicrons
E) Death of ingested bacteria

Question 48

The major enzyme produced by the stomach is

A) amylase.
B) chyme.
C) mucus.
D) pepsin.
E) trypsin.

Question 49

The gut of a vertebrate is often described as an elongated tube consisting of four layers of different cell types. Which of the following represents the correct order of those layers, from innermost (lumen-facing) to outermost?

A) Submucosa, cartilage, mucosa, endoplasmic reticulum
B) Smooth muscle layers, submucosa, mucosa, cartilage
C) Cartilage, smooth muscle layers, mucosa, circular muscle
D) Mucosa, submucosa, circular muscle, longitudinal muscle
E) Cartilage, mucosa, endoplasmic reticulum, submucosa

Question 50

Which of the following statements about digestion in the small intestine is false?

A) Most digestion occurs in the duodenum of the small intestine.
B) Fat in the small intestine is emulsified by bile that is produced by the liver and stored in the gallbladder.
C) Bile molecules in the small intestine have one end that is lipophobic and one end that is hydrophilic.
D) The pancreas secretes zymogens and bicarbonate ions into the duodenum of the small intestine.
E) Enterokinase is secreted by intestinal mucosal cells.

Question 51

Which of the following structures is not used to grind food into fragments?

A) Radula
B) Gizzard
C) Crop
D) Mandible
E) Tooth

Question 52

Which of the following statements about the tubular digestive tract of animals is false?

A) Food is digested extracellularly.
B) There are two openings to the digestive tract.
C) Food must always be broken into smaller pieces before ingestion.
D) All digestion occurs inside the digestive tract.
E) The digestive tract has specialized segments.

Question 53

Most gastric (stomach) ulcers are caused by

A) stress.
B) an infectious bacterium.
C) the oversecretion of digestive juices.
D) old age.
E) an acidic diet.

Question 54

Which structure of the vertebrate gut is a membrane covering the abdominal organs?

A) Circular muscle layer
B) Mucosal layer
C) Submucosal layer
D) Peritoneum
E) Longitudinal muscle layer

Question 55

Which of the following statements about movement of food in the gut is false?

A) Three sphincters are found in the vertebrate gut.
B) Peristalsis can move food in both directions.
C) Stretched smooth muscle contracts.
D) Peristalsis begins when food enters the glottis.
E) The muscle in a sphincter is normally contracted.

Question 56

Which of the following structures of a tubular digestive tract is involved mainly with water and ion recovery?

A) Gizzard
B) Buccal cavity
C) Stomach
D) Hindgut
E) Midgut

Question 57

In the stomach, pepsin activates pepsinogen molecules in a positive feedback process called

A) emulsification.
B) absorption.
C) autocatalysis.
D) rumination.
E) excretion.

Question 58

Which of the following structures does not serve to increase surface area for nutrient absorption?

A) A human's intestinal villi
B) An earthworm's infolding of the intestinal wall
C) A shark's spiral valve
D) A bird's gizzard
E) A human intestinal microvilli

Question 59

In the small intestine, the blood and lymph vessels that carry away absorbed nutrients lie in the _______ layer.

A) microvilli
B) mucosa
C) submucosa
D) circular muscle
E) longitudinal muscle

Question 60

Which of the following structures is not encountered by a food bolus as it is swallowed?

A) Epiglottis
B) Larynx
C) Soft palate
D) Pharynx
E) Esophagus

Question 61

Which of the following statements about digestion is false?

A) The enzymes that carry out the final step in the digestion of proteins are secreted by the pancreas.
B) The enzymes that carry out the final step in the digestion of proteins produce absorbable tripeptides, dipeptides, and amino acids.
C) The enzymes that carry out the final step in the digestion of the common disaccharides are produced by the intestinal epithelial cells.
D) The enzymes that carry out the final step in the digestion of the common disaccharides produce absorbable monosaccharides.
E) Unabsorbed lactose is metabolized by bacteria in the colon.

Question 62

The hormone secretin is a chemical message

A) secreted by the pancreas.
B) secreted by the stomach.
C) whose release is stimulated by the nervous system.
D) that triggers the intestine to release enzymes.
E) that triggers pancreatic secretion.

Question 63

The major function of the colon, or large intestine, is the

A) digestive breakdown of foods.
B) absorption of nutrients from foods.
C) housing of parasitic bacteria.
D) secretion of bile and enzymes.
E) reabsorption of water.

Question 64

The first hormone ever discovered was

A) testosterone.
B) gastrin.
C) secretin.
D) gluconeogenase.
E) glucagon.

Question 65

Ruminant animals, such as goats and cows,

A) produce enzymes in their guts that break down cellulose.
B) practice coprophagy.
C) have a four-chambered stomach that provides a large surface area for better nutrient absorption.
D) produce hydrogen sulfide, an important greenhouse gas.
E) get much of their protein from the digestion of microorganisms.

Question 66

Which of the following statements about gastrin is false?

A) It stimulates secretion of pepsin.
B) It stimulates secretion of HCl.
C) It is activated by low pH.
D) It increases motility in the stomach.
E) It is secreted in the lower part of the stomach.

Question 67

Eating a small serving of a food that is very acidic might present something of a paradox to your stomach because

A) the stomach can handle a low pH well, but might not detect its presence if the serving size is too small.
B) the presence of food in the stomach typically causes release of gastrin, but low pH inhibits release of gastrin.
C) it could lead to overly acidic conditions in the stomach.
D) the presence of food in the stomach typically causes release of pepsin, but low pH inhibits release of pepsin.
E) the high pH of the food could trigger release of bile in the stomach.

Question 68

A lipase is an enzyme that breaks down

A) carbohydrates.
B) nucleic acids.
C) proteins.
D) fat molecules.
E) fatty acids.

Question 69

The vertebrate gut is analogous to a(n)

A) assembly line building cars.
B) junkyard where pieces of cars are removed one by one.
C) cornfield capturing sunlight to form carbohydrates.
D) migrating herd of wildebeest.
E) chef combining ingredients to produce a meal.

Question 70

Which of the following is the true stomach of a ruminant?

A) Cecum
B) Reticulum
C) Rumen
D) Omasum
E) Abomasum

Question 71

Bile aids in the breakdown of lipids by

A) hydrolyzing lipids.
B) activating hydrolytic enzymes.
C) aggregating droplets of lipids.
D) emulsifying lipids.
E) making lipids water soluble.

Question 72

Which of the following statements about the role of the large intestine in digestion is true?

A) If too much water is reabsorbed from the feces, diarrhea results.
B) The large intestine produces digestive enzymes.
C) Helicobacter pylori is a normal inhabitant of the large intestine.
D) The cecum is a fermentation chamber extending from the large intestine.
E) The appendix is a vestigial colon.

Question 73

Low-density lipoproteins are _______ percent protein, _______ percent lipids, and _______ percent cholesterol.

A) 25; 50; 25
B) 30; 30; 40
C) 30; 40; 30
D) 25; 25; 50
E) 35; 30; 35

Question 74

The acidic chyme in the small intestine is neutralized by

A) bicarbonate from the pancreas.
B) buffers from the jejunum.
C) bile from the liver.
D) trypsin activation.
E) a variety of zymogens.

Question 75

Which of the following proteases is produced by the small intestine?

A) Dipeptidase
B) Chymotrypsin
C) Trypsin
D) Carboxypeptidase
E) Pepsin

Question 76

Which of the following activities is not carried out by the liver in the regulation of fuel metabolism?

A) Conversion of nutrients into glycogen and fat
B) Gluconeogenesis
C) Synthesis of plasma proteins from amino acids
D) Production of high-density lipoproteins (HDL) for deposit in adipose tissue
E) Processing of chylomicrons from the small intestine

Question 77

The enzyme lactase

A) cleaves lactose into glucose and galactose.
B) is produced by the small intestine.
C) is not produced by many humans after childhood.
D) cleaves milk sugar.
E) All of the above

Question 78

Most absorption of nutrients in the digestive tract takes place in the

A) stomach.
B) small intestine.
C) large intestine.
D) liver.
E) pancreas.

Question 79

One of the consequences of smoking is a lowered level of _______, which are beneficial molecules that accept cholesterol and probably remove it from the tissues to the liver.

A) chylomicrons
B) very-low-density lipoproteins
C) low-density lipoproteins
D) high-density lipoproteins
E) cholecystokinin

Question 80

How does cotransport of sodium in a symport facilitate glucose absorption?

A) Active transport of sodium aids in salt uptake.
B) When sodium diffuses into cells, glucose is carried along with it.
C) When sodium is pumped into cells, glucose moves out of the cells.
D) Sodium and glucose both diffuse into cells from the gut.
E) Glucose is actively transported into the gut.