Question 1

A termite's digestive organs produce a cellulase that allows it to break down wood fibers.

Accepted Answer

A) True 
 B)False  False

Question 2

A ketose can be converted to an aldose through an enediol intermediate.What is the structure of the enediol intermediate when D-fructose is converted to D-glucose?

Accepted Answer

A) 
  
B) 
  
C) 
  
D) 
  
E) 
  
A) 
  
B) 
  
C) 
  
D) 
  
E) 
  B

Question 3

Biological molecules do not undergo the same reactions as organic molecules because their functional groups have different reactivities.

Accepted Answer

A) True 
 B)False  False

Question 4

What term describes carbohydrates consisting of two to ten monosaccharide units bonded together?

Accepted Answer

A) disaccharide 
B) polysaccharide 
C) oligosaccharide 
D) glycogen 
E) starch 
A) disaccharide 
B) polysaccharide 
C) oligosaccharide 
D) glycogen 
E) starch

Question 5

Amylose and amylopectin are both components of starch.How do their structures differ?

Accepted Answer

A) Amylose is a monosaccharide and amylopectin is a polysaccharide. 
B) Amylose is a polysaccharide and amylopectin is a disaccharide. 
C) Amylose is an aldose and amylopectin is a ketose. 
D) Amylose is a linear polysaccharide and amylopectin is a branched polysaccharide. 
E) Amylose is a hexose and amylopectin is a pentose. 
A) Amylose is a monosaccharide and amylopectin is a polysaccharide. 
B) Amylose is a polysaccharide and amylopectin is a disaccharide. 
C) Amylose is an aldose and amylopectin is a ketose. 
D) Amylose is a linear polysaccharide and amylopectin is a branched polysaccharide. 
E) Amylose is a hexose and amylopectin is a pentose.

Question 6

Why are humans not able to digest cellulose?

Accepted Answer

A) Humans lack the enzyme cellulase,which is required to hydrolyze the β(1→4)glycosidic bonds present in cellulose. 
B) Humans lack the enzyme lactase,which is required to hydrolyze the lactose produced from the digestion of cellulose into glucose and galactose. 
C) Humans lack the enzyme lactase,which is required to convert the galactose produced from the digestion of cellulose into glucose. 
D) Cellulose is not naturally available to humans. 
E) Humans actually can readily digest cellulose. 
A) Humans lack the enzyme cellulase,which is required to hydrolyze the β(1→4)glycosidic bonds present in cellulose. 
B) Humans lack the enzyme lactase,which is required to hydrolyze the lactose produced from the digestion of cellulose into glucose and galactose. 
C) Humans lack the enzyme lactase,which is required to convert the galactose produced from the digestion of cellulose into glucose. 
D) Cellulose is not naturally available to humans. 
E) Humans actually can readily digest cellulose.

Question 7

Monosaccharides exist predominantly as cyclic hemiacetals.Cyclic hemiacetals have both an α and a β form.Which of the following monosaccharides are shown in the β form?

Accepted Answer

A) III only 
B) IV only 
C) I and III 
D) II and IV 
E) All are shown in the β form. 
A) III only 
B) IV only 
C) I and III 
D) II and IV 
E) All are shown in the β form.

Question 8

What type of compound is produced in the reaction between an alcohol and an aldehyde?

Accepted Answer

A) diol 
B) carboxylic acid 
C) acetal 
D) hemiacetal 
E) ester 
A) diol 
B) carboxylic acid 
C) acetal 
D) hemiacetal 
E) ester

Question 9

What test can be used to distinguish between a reducing sugar and a nonreducing sugar?

Accepted Answer

A) iodine test 
B) urine test 
C) chromic acid test 
D) Benedict's test 
E) hydrolysis test 
A) iodine test 
B) urine test 
C) chromic acid test 
D) Benedict's test 
E) hydrolysis test

Question 10

Cellulose molecules are all unbranched,while starch contains only branched molecules.

Accepted Answer

A) True 
 B)False

Question 11

Carbohydrates are chiral or "handed" biomolecules.What does the term chiral describe?

Accepted Answer

A) a molecule that has a mirror image 
B) a molecule that can be superimposed on its mirror image 
C) a molecule that exists in two nonsuperimposable mirror image forms 
D) a molecule that can be digested by the body 
E) a molecule that may be synthesized by the body 
A) a molecule that has a mirror image 
B) a molecule that can be superimposed on its mirror image 
C) a molecule that exists in two nonsuperimposable mirror image forms 
D) a molecule that can be digested by the body 
E) a molecule that may be synthesized by the body

Question 12

How does the structure of α-D-glucose differ from that of β-D-glucose?

Accepted Answer

A) α-D-Glucose is an aldose and β-D-glucose is a ketose. 
B) In α-D-glucose the −OH group on the last chiral carbon is on the left,and in β-D-glucose the −OH group on the last chiral carbon is on the right. 
C) In α-D-glucose the −OH group on the hemiacetal carbon is below the ring,and in β-D-glucose the −OH group on the hemiacetal carbon is above the ring. 
D) In α-D-glucose the last −CH2OH group is on the right,and in β-D-glucose the −CH2OH group is on the left. 
E) There is no structural difference between the two. 
A) α-D-Glucose is an aldose and β-D-glucose is a ketose. 
B) In α-D-glucose the −OH group on the last chiral carbon is on the left,and in β-D-glucose the −OH group on the last chiral carbon is on the right. 
C) In α-D-glucose the −OH group on the hemiacetal carbon is below the ring,and in β-D-glucose the −OH group on the hemiacetal carbon is above the ring. 
D) In α-D-glucose the last −CH2OH group is on the right,and in β-D-glucose the −CH2OH group is on the left. 
E) There is no structural difference between the two.

Question 13

What type of product forms in the intramolecular reaction between the aldehyde portion of the glucose molecule below and its C-5 hydroxyl group?

Accepted Answer

A) disaccharide 
B) ester 
C) carboxylic acid 
D) stereoisomer 
E) hemiacetal 
A) disaccharide 
B) ester 
C) carboxylic acid 
D) stereoisomer 
E) hemiacetal

Question 14

Which property of D-glyceraldehyde and L-glyceraldehyde differs?

Accepted Answer

A) melting point 
B) solubility 
C) direction of rotation of plane-polarized light 
D) density 
E) None of the choices are correct. 
A) melting point 
B) solubility 
C) direction of rotation of plane-polarized light 
D) density 
E) None of the choices are correct.

Question 15

Which of the following is a nonreducing disaccharide?

Accepted Answer

A) mannose 
B) maltose 
C) sucrose 
D) lactose 
E) ribose 
A) mannose 
B) maltose 
C) sucrose 
D) lactose 
E) ribose

Question 16

Which of the following statements concerning carbohydrates is INCORRECT?

Accepted Answer

A) Carbohydrates serve important energy and structural roles for plants and animals. 
B) Monosaccharides are the simplest carbohydrates and are known as simple sugars. 
C) Monosaccharides join together to form disaccharides and polysaccharides by hydrogen bonding. 
D) Humans store excess glucose for short-term energy requirements in the polysaccharide glycogen. 
E) Carbohydrates that can be oxidized by the Benedict's reagent are known as reducing sugars. 
A) Carbohydrates serve important energy and structural roles for plants and animals. 
B) Monosaccharides are the simplest carbohydrates and are known as simple sugars. 
C) Monosaccharides join together to form disaccharides and polysaccharides by hydrogen bonding. 
D) Humans store excess glucose for short-term energy requirements in the polysaccharide glycogen. 
E) Carbohydrates that can be oxidized by the Benedict's reagent are known as reducing sugars.

Question 17

A meso compound is a chiral compound because it contains two chiral carbons and an internal plane of symmetry.

Accepted Answer

A) True 
 B)False

Question 18

What two monosaccharides combine to form sucrose?

Accepted Answer

A) glucose and galactose 
B) galactose and fructose 
C) ribose and galactose 
D) glucose and fructose 
E) ribose and fructose 
A) glucose and galactose 
B) galactose and fructose 
C) ribose and galactose 
D) glucose and fructose 
E) ribose and fructose

Question 19

Which statement is FALSE?

Accepted Answer

A) Molecules that contain a chiral carbon will rotate plane-polarized light. 
B) If one molecule rotates plane-polarized light clockwise 10°,its enantiomer will rotate plane-polarized light counterclockwise by 10°. 
C) The D- and L- designation of sugars is determined by the chiral atom farthest from the most oxidized carbon. 
D) All sugars designated with a D- prefix will rotate plane-polarized light in a clockwise direction. 
E) Dextrorotatory sugars rotate plane-polarized light clockwise and are designated by a plus sign (+). 
A) Molecules that contain a chiral carbon will rotate plane-polarized light. 
B) If one molecule rotates plane-polarized light clockwise 10°,its enantiomer will rotate plane-polarized light counterclockwise by 10°. 
C) The D- and L- designation of sugars is determined by the chiral atom farthest from the most oxidized carbon. 
D) All sugars designated with a D- prefix will rotate plane-polarized light in a clockwise direction. 
E) Dextrorotatory sugars rotate plane-polarized light clockwise and are designated by a plus sign (+).

Question 20

What complex carbohydrate provides a source of dietary fiber?

Accepted Answer

A) starch 
B) cellulose 
C) lactose 
D) sucrose 
E) glucose 
A) starch 
B) cellulose 
C) lactose 
D) sucrose 
E) glucose

Exam 16: Carbohydrates

A termite's digestive organs produce a cellulase that allows it to break down wood fibers.

A ketose can be converted to an aldose through an enediol intermediate.What is the structure of the enediol intermediate when D-fructose is converted to D-glucose?

Biological molecules do not undergo the same reactions as organic molecules because their functional groups have different reactivities.

What term describes carbohydrates consisting of two to ten monosaccharide units bonded together?

Amylose and amylopectin are both components of starch.How do their structures differ?

Why are humans not able to digest cellulose?

Monosaccharides exist predominantly as cyclic hemiacetals.Cyclic hemiacetals have both an α and a β form.Which of the following monosaccharides are shown in the β form?

What type of compound is produced in the reaction between an alcohol and an aldehyde?

What test can be used to distinguish between a reducing sugar and a nonreducing sugar?

Cellulose molecules are all unbranched,while starch contains only branched molecules.

Carbohydrates are chiral or "handed" biomolecules.What does the term chiral describe?

How does the structure of α-D-glucose differ from that of β-D-glucose?

What type of product forms in the intramolecular reaction between the aldehyde portion of the glucose molecule below and its C-5 hydroxyl group?

Which property of D-glyceraldehyde and L-glyceraldehyde differs?

Which of the following is a nonreducing disaccharide?

Which of the following statements concerning carbohydrates is INCORRECT?

A meso compound is a chiral compound because it contains two chiral carbons and an internal plane of symmetry.

What two monosaccharides combine to form sucrose?

Which statement is FALSE?

What complex carbohydrate provides a source of dietary fiber?

Chemistry - Methods and Measurement

The Structure of the Atom and the Periodic Table

Structure and Properties of Ionic and Covalent Compounds

Calculations, chemical Changes, and the Chemical Equation

States of Matter: Gases, liquids, and Solids

Solutions

Energy,rate and Equilibrium

Acids and Bases

The Nucleus, radioactivity, and Nuclear Medicine

An Introduction to Organic Chemistry

The Unsaturated Hydrocarbons: Alkenes, alkynes, and Aromatics

Alcohols, phenols, thiols, and Ethers

Aldehydes and Ketones

Carboxylic Acids and Carboxylic Acid Derivatives

Amines and Amides

Lipids and Their Functions in Biochemical Systems

Protein Structure and Function

Enzymes

Introduction to Molecular Genetics

Carbohydrate Metabolism

Aerobic Respiration and Energy Production

Fatty Acid Metabolism

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