Question 1

The suface area of the small intestine is dramatically increased due to the presence of _________ on the luminal surface.
A)villi and microvilli
B)lacteals
C)capillaries
D)hydrolytic enzymes
E)smooth muscle

Accepted Answer

The presence of villi and microvilli on the luminal surface of the small intestine greatly increases its surface area, allowing for more efficient absorption of nutrients. Lacteals and capillaries are involved in nutrient absorption but do not contribute to an increase in surface area. Hydrolytic enzymes are involved in chemical digestion but do not contribute to an increase in surface area. Smooth muscles are involved in peristalsis and movement of food through the digestive tract, but again, do not contribute to an increase in surface area.

Question 2

Surgical removal of the pancreas would
A)increase the acidity of the small intestine.
B)prevent the production of chyme in the stomach.
C)eliminate the ability to store bile in the gallbladder.
D)block the secretion of bile.
E)All of these changes would be a result of pancreas removal.

Accepted Answer

The pancreas produces bicarbonate, which neutralizes stomach acid in the small intestine. Without the pancreas, this neutralization would not occur, leading to increased acidity in the small intestine.

Question 3

Birds store food in a modified portion of the lower esophagus called the
A)crop.
B)epiglottis.
C)gizzard.
D)alimentary canal.
E)pharynx.

Accepted Answer

Birds store food in a modified portion of the lower esophagus called the crop.

Question 4

How does the digestion and absorption of fat differ from that of carbohydrates?
A)Processing of fat does not require any digestive enzymes,whereas the processing of carbohydrates does.
B)Fat absorption occurs in the stomach,whereas carbohydrates are absorbed from the small intestine.
C)Carbohydrates need to be emulsified before they can be digested,whereas fats do not.
D)Most absorbed fat enters the lymphatic system,whereas carbohydrates directly enter the blooD.
E)Fat must be partially digested by bacteria in the large intestine before it can be absorbed,which is not the case for carbohydrates.

Accepted Answer

Unlike carbohydrates, most absorbed fat enters the lymphatic system because it cannot be transported directly into the bloodstream. This is because fat molecules are too large to pass through the walls of capillaries in the small intestine. Once in the lymphatic system, the fat is transported to the bloodstream and then to the body's cells for use as energy or storage.

Question 5

A digestive cavity in which food enters an opening at one end and passes through the animal in one direction as it is digested is called the
A)gastrovascular cavity.
B)stomach.
C)alimentary canal.
D)epithelial cavity.
E)intestinE.

Accepted Answer

The alimentary canal, also known as the digestive tract, is a continuous tube through which food enters at one end (mouth) and waste exits at the other end (anus), passing in one direction as it is digested and absorbed. This distinguishes it from a gastrovascular cavity, which typically has a single opening serving as both mouth and anus.

Question 6

In ruminants,cellulose digestion occurs in the
A)omasum.
B)rumen.
C)reticulum.
D)cecum.
E)rumen and reticulum.

Accepted Answer

Cellulose digestion in ruminants primarily occurs in the rumen and reticulum, where microorganisms break down cellulose into volatile fatty acids that the animal can absorb and use as energy.

Question 7

When comparing two stomach samples in the lab,you can distinguish the sample taken from a cow from the human sample by the presence of
A)cellulase.
B)pepsin.
C)collagenase.
D)carboxypeptidase.
E)acetylcholinesterasE.

Accepted Answer

Cellulase is an enzyme that breaks down cellulose, a complex carbohydrate found in plant cell walls. Cows have a specialized stomach chamber called the rumen where cellulose digestion occurs, facilitated by microbes that produce cellulase. Humans do not have this specialized chamber or the ability to produce cellulase in their stomachs. Therefore, the presence of cellulase in the stomach sample would indicate that it came from a cow.

Question 8

What is peristalsis?
A)a process of fat emulsification in the small intestine
B)voluntary control of the rectal sphincters regulating defecation
C)the transport of nutrients to the liver through the hepatic portal vein
D)loss of appetite,fatigue,dehydration,and nervous disorders
E)smooth muscle contractions that move food through the alimentary canal

Accepted Answer

Peristalsis is the involuntary muscular contractions that push food and fluid through the digestive system. These contractions happen in the smooth muscles of the intestine and esophagus.

Question 9

How do carnivores and herbivores differ?
A)Carnivores must eat more frequently than herbivores.
B)Carnivores and herbivores require different enzymes to digest their food.
C)Carnivores can be opportunistic but herbivores cannot.
D)Herbivores can be opportunistic but carnivores cannot.
E)Herbivores remain herbivores at all stages of development,while carnivores are often herbivores in their larval stages.

Accepted Answer

Carnivores and herbivores have different dietary requirements, and therefore require different enzymes to digest their food. Carnivores require enzymes to break down protein and fat, while herbivores require enzymes to break down cellulose and other complex carbohydrates found in plants.

Question 10

In the stomach,food processing continues and secretions from stomach glands aid the initial digestion of
A)carbohydrates.
B)lipids.
C)nucleic acids.
D)proteins.
E)vitamins.

Accepted Answer

Secretions from stomach glands aid in the initial digestion of proteins through the action of stomach acid and the enzyme pepsin. Carbohydrates, lipids, nucleic acids, and vitamins are not significantly digested in the stomach.

Question 11

Contrary to popular belief,stress is not usually the primary cause of ulcers,and many patients with ulcers do not over-produce acid.What Nobel prize-winning discovery demonstrated a previously unknown cause of ulcers?
A)greater acid concentrations in the stomach,lower esophagus,and duodenum
B)the eroding effect of certain spicy foods on the lining of the esophagus
C)the existence of a bacterial infection in the stomachs of most patients with ulcers
D)genetically predetermined weakness in the walls of the intestinal tract

Accepted Answer

The discovery of a bacterial infection known as Helicobacter pylori in the stomachs of most patients with ulcers demonstrated a previously unknown cause of ulcers. This discovery led to the development of effective antibiotic treatments for ulcers. Options A, B, and D are incorrect as they do not represent the Nobel prize-winning discovery related to the cause of ulcers.

Question 12

Which type of nutrient can pass across epithelial cells without any expenditure of ATP?
A)iron
B)calcium
C)protein
D)fat
E)magnesium

Accepted Answer

Fats can pass across epithelial cells by simple diffusion, a process that does not require the expenditure of ATP. This is because fats are hydrophobic molecules and can easily diffuse through the lipid bilayer of cell membranes.

Question 13

A mechanism shared by both extracellular and intracellular digestion is
A)the ability to phagocytose food particles.
B)a slow speed of digestion.
C)the presence of a digestive cavity.
D)the ability to consume both large and small food items.

Accepted Answer

Both extracellular and intracellular digestion involve the ability to phagocytose or engulf food particles.

Question 14

Cows are able to survive on a diet consisting almost entirely of cellulose because
A)cows are autotrophic.
B)cows can manufacture all 20 amino acids out of sugars in the liver.
C)unlike humans,the saliva the cow produces has enzymes capable of digesting cellulose.
D)cows have cellulose-digesting,symbiotic microorganisms in their rumens.

Accepted Answer

Cows have cellulose-digesting, symbiotic microorganisms in their rumens that help them break down the cellulose in their diet. This makes it possible for cows to survive on a diet consisting almost entirely of cellulose. Options A and B are not correct as cows are not autotrophic and cannot make all 20 amino acids out of sugars in the liver. Option C is also not correct as cow's saliva does not have enzymes capable of digesting cellulose.

Question 15

One function of HCl secreted in the stomach is to convert pepsinogen into the active enzyme pepsin.Why don't stomach cells simply secrete pepsin instead?
A)Adequate amounts of pepsin are already manufactured by the pancreas.
B)Only the pepsinogen version is able to stabilize fat-water emulsions.
C)Pepsin is denatured and rendered inactive in solutions with low pH.
D)If cells produced active pepsin,they would digest their own cellular proteins.

Accepted Answer

If cells produced active pepsin, they would digest their own cellular proteins, leading to damage and possibly the death of the cells. This is why pepsinogen, an inactive precursor, is secreted instead and then activated to pepsin in the acidic environment of the stomach.

Question 16

Salivary glands secrete _________ to start the digestion of _________.
A)amylase;polysaccharides
B)trypsin;proteins
C)amylase;fats
D)pepsin;proteins
E)lactase;milk

Accepted Answer

Salivary glands secrete amylase to start the digestion of polysaccharides, which are complex carbohydrates like starch and glycogen. Amylase breaks down these polysaccharides into smaller sugars like maltose and glucose.

Question 17

Cats cannot synthesize the amino acid taurine.This means that in cats,taurine
A)is not a required nutrient.
B)is an essential amino acid.
C)must be stored in cellular compartments.
D)is not present in their normal diet.

Accepted Answer

Taurine is considered an essential amino acid for cats because they cannot synthesize it on their own and therefore must obtain it through their diet.

Question 18

The glandular secretions involved in digestion that would most likely be released as inactive precursors are
A)protein-digesting enzymes
B)fat-solubilizing bile salts
C)acid-neutralizing bicarbonate
D)carbohydrate-digesting enzymes

Accepted Answer

Protein-digesting enzymes are typically released as inactive precursors, known as zymogens, to prevent damage to the glandular tissue during secretion. Once in the appropriate environment, such as the stomach for pepsinogen or the pancreas for trypsinogen, the zymogens are activated and can begin to break down proteins.

Note: While the other options may also be released in inactive forms, they are not typically referred to as zymogens.

Question 19

Blockage of the bile duct would be expected to affect
A)lipid digestion.
B)protein digestion.
C)carbohydrate digestion.
D)nucleotide digestion.
E)cellulose digestion.

Accepted Answer

The bile duct carries bile from the liver to the small intestine, where it helps in the digestion and absorption of fats/lipids. If the bile duct is blocked, the flow of bile is disrupted, leading to incomplete digestion and absorption of fats/lipids. This can cause symptoms like abdominal pain, nausea, and diarrhea. Therefore, blockage of the bile duct would affect lipid digestion.

Question 20

Conversion of excess amino acids into carbohydrate and fats during the absorptive state takes place in the
A)liver.
B)brain.
C)intestine.
D)kidney.
E)heart.

Accepted Answer

The answer of Conversion of excess amino acids into carbohydrate...

Quiz 35: Digestive Systems and Nutrition

The suface area of the small intestine is dramatically increased due to the presence of _________ on the luminal surface.

Surgical removal of the pancreas would

Birds store food in a modified portion of the lower esophagus called the

How does the digestion and absorption of fat differ from that of carbohydrates?

A digestive cavity in which food enters an opening at one end and passes through the animal in one direction as it is digested is called the

In ruminants,cellulose digestion occurs in the

When comparing two stomach samples in the lab,you can distinguish the sample taken from a cow from the human sample by the presence of

What is peristalsis?

How do carnivores and herbivores differ?

In the stomach,food processing continues and secretions from stomach glands aid the initial digestion of

Contrary to popular belief,stress is not usually the primary cause of ulcers,and many patients with ulcers do not over-produce acid.What Nobel prize-winning discovery demonstrated a previously unknown cause of ulcers?

Which type of nutrient can pass across epithelial cells without any expenditure of ATP?

A mechanism shared by both extracellular and intracellular digestion is

Cows are able to survive on a diet consisting almost entirely of cellulose because

One function of HCl secreted in the stomach is to convert pepsinogen into the active enzyme pepsin.Why don't stomach cells simply secrete pepsin instead?

Salivary glands secrete _ to start the digestion of _.

Cats cannot synthesize the amino acid taurine.This means that in cats,taurine

The glandular secretions involved in digestion that would most likely be released as inactive precursors are

Blockage of the bile duct would be expected to affect

Conversion of excess amino acids into carbohydrate and fats during the absorptive state takes place in the