Question 1

Proteolytic enzymes secreted from the pancreas are activated
A)once they reach the pancreatic duct.
B)within the lumen of the small intestine.
C)in secretory vesicles within pancreatic secretory cells.
D)once they reach the large intestine.

Accepted Answer

Proteolytic enzymes, such as trypsin and chymotrypsin, are secreted from the pancreas in an inactive form called zymogens. Once they reach the lumen of the small intestine, they are activated by enzymes produced by the intestinal mucosa, such as enterokinase, which converts trypsinogen to trypsin. Therefore, choice B is the best answer. Choices A, C, and D are incorrect because proteolytic enzymes are not activated in these locations.

Question 2

Once micelles enter intestinal epithelial cells,fatty acids and monoglycerides combine to form triglycerides.

Accepted Answer

This statement is true. Once the micelles enter intestinal epithelial cells, the fatty acids and monoglycerides are reassembled into triglycerides.

Question 3

The enzyme pepsin becomes active when pH is
A)high.
B)low.

Accepted Answer

Pepsin is an enzyme that functions in the stomach to break down proteins. It becomes active when the pH in the stomach is low, typically around 1.5-2.5. This acidic environment allows pepsin to function optimally and break down proteins into smaller peptides. Therefore, choice B (low) is the correct answer.

Question 4

Chief cells store and release an inactive precursor of a proteolytic enzyme (rather than the active form)to avoid destroying proteins within themselves.

Accepted Answer

This is true. Chief cells in the stomach mucosa secrete an inactive precursor to pepsin called pepsinogen. This prevents digestion of the chief cells' own proteins before they are secreted into the gastric lumen. Once pepsinogen is released into the acidic environment of the stomach, it is activated by hydrochloric acid and becomes the active enzyme pepsin, which can then break down proteins in food.

Question 5

A complex carbohydrate that consists of several repeating units of simple sugars is referred to as a _________.

Accepted Answer

The answer of A complex carbohydrate that consists of several...

Question 6

Which is an accurate description of glucose and sucrose
A)Glucose is a monosaccharide,sucrose is a polysaccharide,both molecules are starches.
B)Glucose is a monosaccharide,sucrose is a disaccharide,both molecules are carbohydrates.
C)Glucose is a disaccharide,sucrose is a monosaccharide,both molecules are lipids.
D)Glucose is a disaccharide,sucrose is a glycolipid,both molecules are essential nutrients.
E)Glucose is a monoamine,sucrose is a dipeptide,both molecules are acidic.

Accepted Answer

Glucose is a monosaccharide, meaning it is a simple sugar consisting of a single unit. Sucrose, on the other hand, is a disaccharide made up of glucose and fructose units linked together. Both molecules are carbohydrates, which are organic compounds that serve as a major source of energy for living organisms. Therefore, option B accurately describes glucose and sucrose.

Question 7

As a protein is broken down into smaller and smaller fragments,each fragment ultimately requires splitting of the last peptide bond within it.The breaking of the bond between those last two amino acids is catalyzed by the enzyme
A)pepsin.
B)chymotrypsin.
C)dipeptidase.
D)trypsin.
E)glucoamylase.

Accepted Answer

Dipeptidase is the enzyme that catalyzes the breaking of the bond between the last two amino acids in a protein fragment, resulting in the production of individual amino acids. Pepsin, chymotrypsin, and trypsin are all involved in the initial breakdown of proteins into smaller fragments, but do not specifically catalyze the breaking of the last peptide bond. Glucoamylase is involved in the breakdown of carbohydrates, not proteins.

Question 8

Salivary amylase is activated once it enters the acidic environment of the stomach.

Accepted Answer

Salivary amylase, also known as ptyalin, is deactivated by the high acidity of the stomach. It only continues to break down starches once it enters the alkaline environment of the small intestine.

Question 9

Nucleic acids are digested within the
A)mouth.
B)stomach.
C)small intestine.
D)pancreas.
E)large intestine.

Accepted Answer

Nucleic acids are broken down into their nucleotide monomers by pancreatic nucleases and then further broken down by intestinal nucleotidases in the small intestine.

Question 10

Maltase is a brush border enzyme of the small intestine that digests the sugar maltose.

Accepted Answer

Maltase is indeed a brush border enzyme of the small intestine that digests the disaccharide maltose into its component glucose molecules.

Question 11

Bile salts are
A)amphipathic.
B)completely hydrophilic.
C)completely hydrophobic.

Accepted Answer

Bile salts have both hydrophobic and hydrophilic regions, making them amphipathic. This dual nature allows bile salts to emulsify fats and aid in their digestion and absorption.

Question 12

Amylase from saliva digests
A)lipids.
B)protein.
C)glucose.
D)starch.

Accepted Answer

Amylase from saliva specifically digests starch, breaking it down into smaller carbohydrate molecules. It does not digest lipids or proteins, and while it may contribute to the breakdown of some glucose, this is not its primary function.

Question 13

The process by which bile breaks up large fat droplets into smaller ones is called __________.

Accepted Answer

The answer of The process by which bile breaks up...

Question 14

Bile catalyzes the breakdown of triglyceride into a monoglyceride and two free fatty acids.

Accepted Answer

The answer of Bile catalyzes the breakdown of triglyceride into...

Question 15

Digestion of carbohydrates within the small intestine involves enzymes that come from the
A: mouth.
B: stomach.
C: pancreas.
D: lining of the small intestine.
A)a,b
B)b,c
C)c,d
D)a,d
E)a,b,c,d

Accepted Answer

Digestion of carbohydrates within the small intestine involves enzymes that come from the pancreas and the lining of the small intestine. Enzymes from the mouth and stomach are involved in the initial stages of carbohydrate digestion, but not within the small intestine.

Question 16

Pepsinogen is an
A)active enzyme that is released in the small intestine and digests carbohydrates.
B)inactive precursor to the enzyme pepsin that digests proteins in the stomach.
C)active enzyme that digests proteins within the small intestine.
D)inactive precursor to a nonspecific enzyme that is synthesized in the pancreas and released in the small intestine.

Accepted Answer

Pepsinogen is an inactive precursor to the enzyme pepsin that digests proteins in the stomach. It is released by the chief cells in the stomach and is activated by the acidic environment of the stomach to form pepsin.

Question 17

Digestion of proteins is initiated by the enzyme
A)amylase.
B)hydrochloric acid.
C)aminopeptidase.
D)pepsin.
E)CCK.

Accepted Answer

Pepsin is the enzyme that initiates the digestion of proteins in the stomach. Amylase breaks down carbohydrates, hydrochloric acid helps to denature proteins, aminopeptidase breaks down small peptides, and CCK stimulates the release of enzymes from the pancreas for protein digestion, but does not initiate it.

Question 18

Within intestinal epithelial cells,lipids are wrapped in a protein coat to form __________,which will be packaged into secretory vesicles at the Golgi apparatus.or

Accepted Answer

The answer of Within intestinal epithelial cells,lipids are wrapped in...

Question 19

Carboxypeptidase is an enzyme that helps digest
A)amino acids within the stomach.
B)complex carbohydrates within the small intestine.
C)peptides within the small intestine.
D)disaccharides within the duodenum.
E)starch within the stomach.

Accepted Answer

Carboxypeptidase is an enzyme that helps digest peptides within the small intestine by breaking them down into individual amino acids. It is not involved in the digestion of carbohydrates or disaccharides.

Question 20

Lactose intolerant individuals cannot digest the _________ lactose because they lack the enzyme _________.
A)polysaccharide;maltase
B)disaccharide;lactase
C)monosaccharide;dextrolactase
D)lipid;pancreatic lipase
E)fatty acid;sucrolactase

Accepted Answer

Lactose intolerant individuals cannot digest the disaccharide lactose because they lack the enzyme lactase.

Quiz 26: Digestive System

Proteolytic enzymes secreted from the pancreas are activated

Once micelles enter intestinal epithelial cells,fatty acids and monoglycerides combine to form triglycerides.

The enzyme pepsin becomes active when pH is

Chief cells store and release an inactive precursor of a proteolytic enzyme (rather than the active form)to avoid destroying proteins within themselves.

A complex carbohydrate that consists of several repeating units of simple sugars is referred to as a _________.

Which is an accurate description of glucose and sucrose

As a protein is broken down into smaller and smaller fragments,each fragment ultimately requires splitting of the last peptide bond within it.The breaking of the bond between those last two amino acids is catalyzed by the enzyme

Salivary amylase is activated once it enters the acidic environment of the stomach.

Nucleic acids are digested within the

Maltase is a brush border enzyme of the small intestine that digests the sugar maltose.

Bile salts are

Amylase from saliva digests

The process by which bile breaks up large fat droplets into smaller ones is called __________.

Bile catalyzes the breakdown of triglyceride into a monoglyceride and two free fatty acids.

Digestion of carbohydrates within the small intestine involves enzymes that come from the A: mouth. B: stomach. C: pancreas. D: lining of the small intestine.

Pepsinogen is an

Digestion of proteins is initiated by the enzyme

Within intestinal epithelial cells,lipids are wrapped in a protein coat to form __________,which will be packaged into secretory vesicles at the Golgi apparatus.or

Carboxypeptidase is an enzyme that helps digest

Lactose intolerant individuals cannot digest the _ lactose because they lack the enzyme _.