Deck 20: Biochemistry: the Compounds of Life

Question 1

Which of the following statements is not correct? Triglycerides __________

A) have both structural isomers and stereoisomers.
B) are soluble in water.
C) are made from glycerol combining with three fatty acids.
D) are lipids.
E) have ester groups.

Answer 1

are soluble in water.

Question 2

Which of the following compounds is an $\alpha$ -amino acid?

A)
B)
C)
D)

Answer 2

Question 3

How many different nucleotides are used to create DNA and RNA?

A) 2
B) 5
C) 3
D) 4
E) 6

Answer 3

5

Question 4

At a physiological pH of 7.4, amino acids exist as zwitterions. At a very low pH (in an acid solution), both the amine group and the carboxylic acid group on an amino acid are protonated. Which acid group is the stronger acid?

A) -NH₂
B) -NH₃⁺
C) -COOH
D) -COO^-
E) -H₃O⁺

Question 5

Which of the following is not a lipid?

A) fatty acid esters
B) cholesterol
C) fats
D) cellulose
E) oils

Question 6

How many different nucleic acid bases are found in DNA and RNA?

A) 2
B) 5
C) 3
D) 4
E) 6

Question 7

At a physiological pH of 7.4, amino acids exist as zwitterions. At a very low pH (in an acid solution), both the amine group and the carboxylic acid group on an amino acid are protonated. Therefore, the following must be true: the pK_a of the __________ group is larger than the pK_a of the __________ group.

A) protonated amine group / carboxylic acid group
B) carboxylic acid group / protonated amine group
C) amine group / carbonate group
D) hydronium ion group / hydroxyl ion group
E) carbonate group / amine group

Question 8

Which of the following are amino acids?
I.
II.
III.
IV.

A) III and IV
B) I and II
C) I only
D) II only
E) III only

Question 9

An α-amino acid is one in which the amine group and the carboxylic acid group are attached to __________

A) different carbon atoms.
B) different nitrogen atoms.
C) the same carbon atom.
D) the first and third carbon of the molecule.
E) neighboring carbon atoms.

Question 10

Which statement about amino acid enantiomers is not correct?

A) An enantiomer cannot be superimposed on its mirror image.
B) Enantiomers are examples of stereoisomers.
C) A solution of an enantiomer rotates the plane of polarized light.
D) Enantiomers are designated by the prefixes D and L.
E) All the chiral amino acids in our bodies are mixtures of enantiomers.

Question 11

An amino acid is composed of __________

A) ammonia and a carboxylic acid group.
B) an amine and a carboxylic acid group.
C) an amine and an alcohol group.
D) an amine and a sulfonic acid group.
E) an amide and a hydrochloric acid group.

Question 12

At a physiological pH of 7.4, amino acids exist as zwitterions because the pK_a of the -NH₃⁺ group is __________ 7.4, and the pK_a of the -COOH group is __________ 7.4.

A) greater than / less than
B) less than / greater than
C) greater than / greater than
D) less than / less than
E) equal to / equal to

Question 13

Isomers that cannot be superimposed on their mirror images are called __________

A) geometric isomers.
B) structural isomers.
C) enantiomers.
D) isotopes.
E) constitutional isomers.

Question 14

Which of the following is a monosaccharide?

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

Question 15

The following reaction produces a peptide. Which statement about this reaction is not correct?

A) The peptide shown is the only product produced by this reaction.
B) This condensation reaction produces a peptide bond.
C) An amide group is formed in this reaction.
D) An amino group reacts with a carboxylic acid group.
E) Two amino acids are linked together by this reaction.

Question 16

Which statement about chirality is not correct?

A) A molecule is chiral if it has a carbon atom bonded to four different groups.
B) A molecule is chiral if it cannot be superimposed on its mirror image.
C) Almost all amino acids are chiral.
D) In an amino acid, the alpha carbon is the chiral center.
E) Chiral amino acids each have three enantiomers.

Question 17

Which of the following are not amino acids?
I.
II.
III.
IV.

A) III and IV
B) I and II
C) I only
D) II only
E) III only

Question 18

Which of the following is not part of a nucleotide?

A) a five-carbon sugar
B) a phosphate group
C) a nitrogen-containing base
D) an amine group
E) a carboxylic acid group

Question 19

Triglycerides are formed between __________

A) glycerol and inorganic acids.
B) glucose and long-chain fatty acids.
C) glycerol and long-chain fatty acids.
D) glycerol and any carboxylic acid.
E) glucose, fructose, and sucrose.

Question 20

Which statement is not correct? A chiral molecule __________

A) is an enantiomer.
B) rotates the plane of polarized light.
C) has four different groups bonded to the same carbon atom.
D) has properties different from those of its mirror image.
E) can be superimposed on its mirror image.

Question 21

The ordering of subunits, such as amino acids, in a polymer, is called __________

A) the primary structure.
B) the secondary structure.
C) the tertiary structure.
D) the ordering structure.
E) the quaternary structure.

Question 22

The cyclization of glucose forms a __________

A) four-membered ring.
B) five-membered ring.
C) six-membered ring.
D) seven-membered ring.
E) double ring.

Question 23

The active ingredient, sucralose, in an artificial sweetener, Splenda, is shown below. Sucralose is advertised as being made from table sugar. What is the main difference between sucrose (table sugar) and sucralose?

A) Sucralose is a disaccharide while sucrose is a monosaccharide.
B) Sucralose has a six-membered and a five-membered ring, unlike the two six-membered rings in sucrose.
C) Sucralose has a glycosidic bond between the two saccharide units, unlike the C-C bond in sucrose.
D) Some hydroxyl groups in sucrose are replaced by chlorine atoms in sucralose.
E) Sucralose has a six-membered and a five-membered ring, unlike the two five-membered rings in sucrose.

Question 24

The primary structure of a protein is __________

A) the sequence of amino acids in the protein.
B) the $\alpha$ -helix structure of the protein.
C) the $\beta$ -pleated sheet structure of the protein.
D) a list of the amino acids in the protein along with the number of times each occurs.
E) the arrangement of $\beta$ -helices and $\beta$ -pleated sheets in the protein.

Question 25

The cyclization of fructose forms a __________

A) four-membered ring.
B) five-membered ring.
C) six-membered ring.
D) seven-membered ring.
E) double ring.

Question 26

Table sugar is __________

A) glucose.
B) fructose.
C) cellobiose.
D) a monosaccharide.
E) a disaccharide of glucose and fructose.

Question 27

The Krebs cycle __________

A) produces carbohydrates in photosynthesis.
B) is a series of chemical reactions that assist in extracting energy from glucose.
C) serves to break down cellulose to produce glucose.
D) describes how enzymes act as catalysts.
E) has one more wheel than a tricycle.

Question 28

Which statement is not correct? Sucrose is __________

A) used for table sugar.
B) is a disaccharide.
C) consists of glucose and fructose with a glycosidic bond.
D) formed in a condensation reaction that eliminates water.
E) a synonym for glucose.

Question 29

Amino acids bond together via __________ bonds.

A) ionic
B) coordinate covalent
C) hydrogen
D) peptide
E) van der Waals

Question 30

Aspartame exists as a zwitterion with a __________ amine group and a __________ carboxylic acid group.

A) deprotonated; protonated
B) protonated; deprotonated
C) protonated; protonated
D) deprotonated; deprotonated
E) functionalized; defunctionalized

Question 31

Which of the following is not a description of the secondary structure of a protein?

A) '' $\alpha$ -helix''
B) '' $\beta$ -pleated sheets''
C) random coil
D) sequence of amino acids in the protein
E) geometric patterns formed by amino acids

Question 32

An oligopeptide consists of up to __________ amino acids that bond together.

A) 5
B) 20
C) 10
D) 15
E) 50

Question 33

A peptide bond is the result of a condensation reaction between __________

A) two carboxylic acid groups on different amino acids.
B) an amino group on one amino acid and the carboxylic acid group on another.
C) two amino groups on different amino acids.
D) an amino group and a carboxylic acid group on the same amino acid.
E) an amino group and a carboxylic acid group producing a zwitterion.

Question 34

Table sugar is __________

A) glucose.
B) fructose.
C) cellobiose.
D) a monosaccharide.
E) a disaccharide.

Question 35

The assembly and interaction of coils and sheets in a polypeptide to produce the overall three-dimensional shape are described by the term __________

A) primary structure.
B) secondary structure.
C) tertiary structure.
D) long-range structure.
E) quaternary structure.

Question 36

The $\alpha$ -helix and $\beta$ -pleated sheet are examples of __________

A) primary structure.
B) secondary structure.
C) tertiary structure.
D) arrangement structure.
E) quaternary structure.

Question 37

In glycolysis, __________ is converted into pyruvic acid.

A) sucrose
B) fructose
C) galactose
D) glucose
E) glycolase

Question 38

Table sugar is __________

A) glucose.
B) fructose.
C) cellobiose.
D) a monosaccharide.
E) sucrose.

Question 39

Glucose is shown below. Number the carbon atoms 1-6 from top to bottom. In the cyclization reaction, a bond is formed to C-1 by an oxygen lone pair on the OH bonded to __________

A) C-2.
B) C-4.
C) C-5.
D) C-6.
E) C-3.

Question 40

The cyclization reaction of fructose is different from that of glucose because __________

A) a five-membered ring instead of a six-membered ring is formed.
B) a bond is formed to a carbonyl carbon instead of to a methyl carbon.
C) the aldehyde group migrates to a new position.
D) a ketone is formed.
E) fructose has only 5 carbon atoms total instead of 6 as in sucrose.

Question 41

Mountain folk in Kentucky and Tennessee were sometimes stereotyped for their "corn-liquor" stills that they hid from the "revenue-ers." What is the first step in making corn liquor (ethanol) from corn?

A) fermentation
B) distillation
C) hydrolysis
D) intoxication
E) celebration

Question 42

Which one of the following is a saturated fatty acid?

A)
B)
C)
D)

Question 43

A disaccharide has a molecular formula of __________

A) CH₂O.
B) C₆H₁₀O₅.
C) C₁₂H₂₂O₁₁.
D) C₂H₄O₂.
E) C₁₂H₂₄O₁₂.

Question 44

A carbohydrate has a molecular formula of __________

A) CH₂O.
B) C₆H₁₂O₆.
C) C₁₂H₂₂O₁₁.
D) C₂H₄O₂.
E) C₃H₆O₃.

Question 45

Glucose and fructose undergo a __________ reaction in the formation of sucrose.

A) sugarization
B) precipitation
C) condensation
D) neutralization
E) addition

Question 46

To produce ethanol from corn (i.e., starch) to use as fuel or drink, the starch first must be decomposed to glucose through a process called __________

A) fermentation.
B) distillation.
C) hydrolysis.
D) combustion.
E) oxidation.

Question 47

What is the linkage that forms between two monosaccharides in a polysaccharide?

A) C- CH₂ - C
B) C- O - O - C
C) C- O - C
D) C- C C C
E) C - N - C

Question 48

Converting renewable biomass into fuel to reduce our need to import petroleum and release carbon dioxide from fossil fuels is a great idea. But, to be viable, the process must be cost effective, not subsidized by taxpayer support, and not reduce our supply of food! It also must be recognized that the amount of energy produced through biomass conversion will always be small compared to our total needs. In any case, Professor Popsnorkle's research students at PC University have projects dealing with these issues. Amy's project deals with $\alpha$ -glucoside hydrolysis of starches, and Brad's project deals with $\beta$ -glucoside hydrolysis of cellulose. What do you see as the value of these projects and why?

A) Amy's is more valuable because improving the efficiency of starch hydrolysis will increase the effectiveness of our edible corn for fuel program and reduce the need for taxpayer subsidies.
B) Brad's is more valuable because the hydrolysis of cellulose, which is not edible, to produce glucose and ethanol currently is not economically viable.
C) Both are valuable because anything we can do along these lines merits equitable support.
D) Neither is valuable because these ideas are promoted only to enrich farmers in the Midwest.
E) I have a neutral position on the value of these projects because I do not know enough about these issues.

Question 49

Glucose is to cellulose as __________

A) pure gold is to 14 karat gold.
B) a link is to a chain.
C) a leaf is to a tree.
D) a trumpet is to a tuba.
E) a tomato is to a potato.

Question 50

In its linear form, which functional groups are present in glucose?

A) aldehyde and alcohol
B) aldehyde and carboxyl
C) alcohol and ketone
D) amino and alcohol
E) amino and aldehyde

Question 51

Glucose is to starch as __________

A) pure gold is to 14 karat gold.
B) a link is to a chain.
C) a leaf is to a tree.
D) a trumpet is to a tuba.
E) a tomato is to a potato.

Question 52

A carbohydrate has an empirical formula of __________

A) CH₂O.
B) C₆H₁₂O₆.
C) C₁₂H₂₂O₁₁.
D) C₂H₄O₂.
E) C₃H₆O₃.

Question 53

How many different nucleic acid bases are found altogether in the nucleic acids DNA and RNA?

A) 1
B) 2
C) 3
D) 4
E) 5

Question 54

Which base is not present in DNA?

A) adenine
B) cytosine
C) guanine
D) thymine
E) uracil

Question 55

In its ring structure, which functional groups are present in glucose?

A) ether and alcohol
B) aldehyde and carboxyl
C) alcohol and ketone
D) amino and alcohol
E) amino and aldehyde

Question 56

A saturated fatty acid has __________

A) more than one carboxyl group.
B) a long hydrocarbon chain containing C C and C- C bonds.
C) a long hydrocarbon chain containing only C - C bonds.
D) a long hydrocarbon chain containing only C C bonds.
E) cis and trans isomers.

Question 57

A monosaccharide has a molecular formula of __________

A) CH₂O.
B) C₆H₁₀O₅.
C) C₁₂H₂₂O₁₁.
D) C₂H₄O₂.
E) C₆H₁₂O₆.

Question 58

Hydrolysis is __________

A) any reaction involving hydrogen.
B) breaking a bond by the addition of water.
C) the process of dissolving a solute to make a solution.
D) breaking a bond to produce hydrogen gas.
E) forming a bond by adding hydrogen gas.

Question 59

Which base is not present in RNA?

A) adenine
B) cytosine
C) guanine
D) thymine
E) uracil

Question 60

Which statement is not correct? Starch and cellulose __________

A) are polysaccharides.
B) have monosaccharides joined by glycosidic bonds.
C) are equally easily hydrolyzed to produce glucose.
D) are stereoisomers made from glucose monomers.
E) are a major source of biomass.

Question 61

DNA contains the sugar __________ and the base __________.

A) ribose; uracil
B) deoxyribose; uracil
C) fructose; uracil
D) ribose; thymine
E) deoxyribose; thymine

Question 62

This molecule, like cholesterol, is __________

A) a nucleic acid base.
B) an amino acid.
C) a carbohydrate.
D) a fatty acid.
E) a lipid.

Question 63

RNA contains the sugar __________ and the base __________.

A) ribose; uracil
B) deoxyribose; uracil
C) fructose; uracil
D) ribose; thymine
E) Deoxyribose; uracil

Question 64

Which one of the following is best associated with carbohydrates?

A) amino acids
B) saccharides
C) hydrocarbon chains
D) phosphate linkages
E) hydrocarbon rings

Question 65

The molecule drawn below is an example of __________

A) a nucleic acid base.
B) a peptide.
C) a carbohydrate.
D) a fatty acid.
E) an amino acid.

Question 66

An ether linkage connects monomers in __________

A) proteins.
B) nucleic acids.
C) carbohydrates.
D) lipids.
E) steroids.

Question 67

The molecule drawn below is an example of __________

A) a nucleic acid base
B) an amino acid
C) a carbohydrate
D) a fatty acid
E) a lipid

Question 68

Which of the following triglycerides would you most expect to be a liquid at room temperature?

A) saturated fat
B) trans mono-unsaturated fat
C) trans poly-unsaturated fat
D) cis mono-unsaturated fat
E) cis poly-unsaturated fat

Question 69

Which one of the following is best associated with nucleic acids?

A) amino acids
B) saccharides
C) hydrocarbon chains
D) phosphate linkages
E) hydrocarbon rings

Question 70

Which one of the following is best associated with proteins?

A) amino acids
B) saccharides
C) hydrocarbon chains
D) phosphate linkages
E) hydrocarbon rings

Question 71

Which of the following triglycerides would you most expect to be a liquid and the most healthy to use in cooking?

A) saturated fat
B) trans mono-unsaturated fat
C) trans poly-unsaturated fat
D) cis mono-unsaturated fat
E) cis poly-unsaturated fat

Question 72

mRNA and tRNA are responsible for the synthesis of __________

A) carbohydrates.
B) lipids.
C) proteins.
D) phospholipids.
E) cells.

Question 73

Which type of noncovalent interaction supports the double helix of DNA and produces the base pairings A-T and G-C?

A) hydrogen bonding
B) London dispersion forces
C) dipole-dipole forces
D) ion-ion interactions
E) ion-dipole interactions

Question 74

The molecule drawn below is an example of __________

A) a nucleic acid base.
B) an amino acid.
C) a carbohydrate.
D) a fatty acid.
E) a lipid.

Question 75

Which one of the following statements about biomolecules is not correct?

A) Table sugar (sucrose) is a disaccharide made of glucose and fructose.
B) Starch and cellulose are polysaccharides made from glucose.
C) A glycosidic linkage in polysaccharides is an ether group.
D) Cellobiose is a disaccharide composed of two glucose monomers.
E) Maltose is a disaccharide composed of two fructose monomers.

Question 76

Which of the following saccharides, if any, can be found in a nucleic acid?

A) sucrose
B) glucose
C) fructose
D) ribose
E) None, a nucleic acid is not a carbohydrate.

Question 77

The molecule drawn below is an example of __________

A) a nucleic acid base.
B) an amino acid.
C) a disaccharide.
D) a fatty acid.
E) a lipid.

Question 78

Which of the following sugars is glucose?

A)
B)
C)
D)
E)

Question 79

The molecules drawn below are examples of __________

A) nucleic acids.
B) amino acids.
C) carbohydrates.
D) fatty acids.
E) steroidal acids.

Question 80

Which one of the following is best associated with lipids?

A) amino acids
B) saccharides
C) ribose units
D) phosphate linkages
E) fatty acids