Deck 18: Amino Acids and Proteins

Question 1

All of the following are major functions of proteins except

A)transport of necessary chemicals.
B)protection against foreign substances.
C)support for organs or tissues.
D)control of biochemical reactions.
E)storage of energy.

Answer 1

storage of energy.

Question 2

Which molecule is an alpha amino acid?

A)

B)

C)

D)

E)

Answer 2

Question 3

The side chains or R groups of amino acids can be classified into each of the following categories except

A)polar.
B)non-polar.
C)basic.
D)acidic.
E)isoelectric.

Answer 3

isoelectric.

Question 4

Polar R groups,along with acidic and basic R groups,are said to be ________ because they are attracted to water molecules.

A)hydrophilic
B)hydrophobic
C)ionized
D)unreactive
E)none of these

Question 5

An amino acid whose R group is predominantly hydrocarbon would be classified as

A)polar.
B)non-polar.
C)basic.
D)acidic.
E)isoelectric.

Question 6

Insulin is an example of a(an)

A)enzyme.
B)structural protein.
C)storage protein.
D)transport protein.
E)hormone.

Question 7

Which of the following is the structure for the amino acid with the abbreviation of Asn?

A)

B)

C)

D)

E)

Question 8

Oxytocin is a small protein that induces smooth muscle causing contractions during labor.What class of proteins would this belong to?

A)storage protein
B)transport protein
C)hormone
D)structural protein
E)protective protein

Question 9

Which functional group is least important in biochemistry?

A)amide
B)amine
C)aromatic
D)ester
E)hydroxyl

Question 10

Non-polar R groups on amino acids are said to be ________ because they are not attracted to water molecules.

A)hydrophilic
B)hydrophobic
C)ionized
D)unreactive
E)none of these

Question 11

All of the following can be classified as biomolecules except

A)carbohydrates.
B)proteins.
C)lipids.
D)nucleic acids.
E)All of the above are biomolecules.

Question 12

Which of the following is the structure for the amino acid with the abbreviation of Phe?

A)

B)

C)

D)

E)

Question 13

Which category of amino acid contains R groups that are hydrophobic?

A)polar
B)non-polar
C)basic
D)acidic
E)basic and acidic

Question 14

Collagen is an example of a(an)

A)enzyme.
B)structural protein.
C)storage protein.
D)transport protein.
E)hormone.

Question 15

Two functional groups that are present in all amino acids are the ________ group and the ________ group.

A)hydroxyl;amide
B)carboxyl;amine
C)carboxyl;phosphate ester
D)acetal;amine
E)carbonyl;amide

Question 16

Which of the following amino acids contains an alcohol group?

A)Phe
B)Val
C)Asp
D)Thr
E)Cys

Question 17

Serum albumin is an example of a(an)

A)enzyme.
B)structural protein.
C)storage protein.
D)transport protein.
E)protective protein.

Question 18

Myoglobin is a protein that contains oxygen in the muscle.What class of protein does it belong to?

A)storage protein
B)transport protein
C)structural protein
D)protective protein
E)enzyme

Question 19

Which amino acid is a secondary amine with its nitrogen and the alpha-carbon joined as part of a ring structure?

A)arginine
B)glycine
C)histidine
D)lysine
E)proline

Question 20

Members of which class of biomolecules are the building blocks of proteins?

A)glycerols
B)monosaccharides
C)fatty acids
D)amino acids
E)nucleic acids

Question 21

Which of these amino acids has a thiol group as part of its side chain?

A)cysteine
B)tyrosine
C)histidine
D)threonine
E)methionine

Question 22

Using three letter designation,write the six tripeptides that can be formed from the combination of serine,tyrosine and aspartate.

Question 23

Which amino acid is classified as basic?

A)valine
B)threonine
C)phenylalanine
D)lysine
E)glutamic acid

Question 24

Which amino acid is not chiral?

A)alanine
B)arginine
C)cysteine
D)glycine
E)phenylalanine

Question 25

An amino acid has the form shown at

A)a pH of 7.0.
B)any pH other than 7.0.
C)a pH greater than its isoelectric point.
D)its isoelectric point.
E)a pH less than its isoelectric point.

Question 26

How many different tripeptides can be formed from one molecule each of the amino acids tyrosine,valine,and alanine?

A)3
B)6
C)9
D)12
E)24

Question 27

This question has four parts:

A) For the amino acid shown above in zwitterion form,circle the carboxyl group,underline the amine group,label the alpha carbon,and draw a box around the R group.
B) Write the name and abbreviation of your amino acid.
C) Classify the amino acid as polar,non-polar,acidic,or basic.Explain the basis for your classification.
D)Draw the structure of the amino acid at a pH well below its isoelectric point and well above its isoelectric point.

Question 28

The peptide bond joining amino acids into proteins is a specific example of the ________ bond.

A)amide
B)carbonyl
C)ester
D)glycosidic
E)hydrogen

Question 29

Amino acids used in proteins generally are

A)α-amino acids.
B)l-amino acids.
C)d-amino acids.
D)All are correct.
E)None are correct.

Question 30

The pH at which the positive and negative charges of an amino acid balance each other is called the

A)isoelectric point.
B)isobaric point.
C)isobestic point.
D)isotonic point.
E)isomer point.

Question 31

Amino acids are least soluble in water at

A)their isoelectric point.
B)low pH.
C)neutral pH.
D)high pH.
E)both high and low pH.

Question 32

Which structure represents a zwitterion?

A)

B)

C)

D)

E)

Question 33

Which amino acid is classified as neutral and non-polar?

A)aspartic acid
B)histidine
C)phenylalanine
D)lysine
E)tyrosine

Question 34

Amino acids found in proteins all have which of the following features?

A)All are α-amino acids.
B)All are l-amino acids.
C)All are d-amino acids.
D)All are correct.
E)None are correct.

Question 35

An amino acid will have the form shown at

A)a pH of 7.0.
B)any pH other than 7.0.
C)a pH greater than its isoelectric point.
D)its isoelectric point.
E)a pH less than its isoelectric point.

Question 36

The isoelectric point of an amino acid is the pH

A)at which it exists in the basic form.
B)at which it exists in the acid form.
C)at which it exists in the zwitterion form.
D)equal to its pK_a.
E)equal to its pK_b.

Question 37

The reaction of amino acids to give peptides involves which pair of functional groups?

A)two amino groups
B)two carboxyl groups
C)an amino and a carboxyl group
D)a carboxyl and an alcohol group

Question 38

The tripeptide represented as ala-leu-gly is named

A)alanine-glycine-leucine.
B)alanylglycylleucine.
C)alanine-leucine-glycine.
D)alanylleucylglycine.
E)none of these

Question 39

Which of the following amino acids contains two chiral centers?

A)leucine
B)isoleucine
C)proline
D)valine
E)phenylalanine

Question 40

Draw the tripeptide as it would be found at pH = 7: ala-gly-phe

Question 41

All of the following are globular proteins except

A)myosin.
B)ribonuclease.
C)hemoglobin.
D)albumin.
E)immunoglobulin.

Question 42

Illustrate the backbone of a protein using a planar unit from one Ca carbon to the next Ca.

Question 43

Which type of forces form the primary structure of a protein?

A)peptide
B)hydrogen bonding between the carbonyl group and amino group
C)salt bridges
D)dipole-dipole interactions
E)disulfide bonds

Question 44

Which protein is considered to be a globular protein?

A)albumin
B)keratin
C)collagen
D)myosin

Question 45

In the tetrapeptide Ala-Cys-Val-Leu,the N-terminal amino acid is

A)Ala.
B)Cys.
C)Val.
D)Leu.
E)none of the above

Question 46

The beta-pleated sheet is an example of

A)primary structure.
B)secondary structure.
C)tertiary structure.
D)quaternary structure.
E)none of the above

Question 47

All of the following are examples of fibrous proteins except

A)wool.
B)fingernails.
C)skin.
D)insulin.
E)bones.

Question 48

The two protein chains in insulin are held together by

A)disulfide linkages.
B)hydrophobic interactions.
C)hydrogen bonds.
D)salt bridges.
E)all of the above

Question 49

Where in a protein structure are basic groups located?

A)at the N-terminal end
B)at the C-terminal end
C)on the Lys,Arg,and His side chains
D)both A and C
E)none of the above

Question 50

The difference between normal and sickle cell hemoglobin is in which structure?

A)primary
B)secondary
C)tertiary
D)quaternary

Question 51

All of the following are non-covalent interactions important in maintaining the secondary,tertiary,and quaternary aspects of amino acids except

A)sulfur-sulfur bonds.
B)hydrogen bonding along the backbone.
C)hydrogen bonding between R groups.
D)salt bridges between R groups.
E)hydrophobic interactions between R groups.

Question 52

The type of bond that is most important in maintaining secondary structure of a protein is

A)disulfide bridges.
B)hydrogen bonding within the backbone.
C)hydrogen bonding between R groups.
D)salt bridges.
E)hydrophobic interactions.

Question 53

In the tetrapeptide Ala-Cys-Val-Leu,the C-terminal amino acid is

A)Ala.
B)Cys.
C)Val.
D)Leu.
E)none of the above

Question 54

The type of bonding that maintains the secondary structure in a protein is the

A)hydrogen bonds between the carbonyl and amino groups of the backbone.
B)covalent bond between the carbonyl and amino groups of the amino acids.
C)hydrogen bonds between two amino acids.
D)disulfide bonds that hold two polypeptide chains together.
E)hydrogen bonds between two amino groups.

Question 55

By convention,the N-terminal end of a protein is usually placed on the ________ of a protein structure.

A)right side
B)left side
C)center
D)bottom
E)top

Question 56

The N-terminal amino acid in the peptide Ala-Leu-Gly-His-Pro is

A)alanine.
B)leucine.
C)glycine.
D)histidine.
E)proline.

Question 57

The amino acid sequence of a protein is known as its

A)primary structure.
B)secondary structure.
C)tertiary structure.
D)quaternary structure.
E)none of the above

Question 58

Keratin,the protein of hair and skin,has extensive sections with which secondary structure?

A)beta-pleated sheet
B)alpha-helix
C)random coil
D)alpha-beta

Question 59

Which structure among the following represents an amide (protein)bond?

A)
B)

C)

D)

E)

Question 60

The C-terminal amino acid in the peptide Ala-Leu-Gly-His-Pro is

A)alanine.
B)leucine.
C)glycine.
D)histidine.
E)proline.

Question 61

When a protein is ________,its primary structure is destroyed,thus destroying the other aspects of its structure.

A)denatured
B)hydrolyzed
C)ionized
D)polymerized
E)esterified

Question 62

Which type of interaction is not directly involved in maintaining tertiary structure?

A)disulfide bridges
B)hydrogen bonding
C)peptide bonds
D)salt bridges
E)hydrophobic interactions

Question 63

Match the following.
hydrophobic

A)refers to R groups which form hydrogen bonds with water because of their polarity
B)refers to R groups that do not interact readily with water because they are non-polar
C)a protein that is usually insoluble in water,is very tough,and has a long shape
D)a carbon atom bonded to four different groups and therefore able to form enantiomers
E)a protein that produces amino acids and other biomolecules or inorganic substances
F)a protein with the tertiary structure in which it normally occurs in living systems
G)a protein that produces only amino acids upon hydrolysis
H)a protein that is usually water soluble,having a hydrophilic exterior and hydrophobic interior,and an overall rounded shape
I)the form of an amino acid in which both the carboxyl group and the amine group are charged,but the overall molecule remains neutral

Question 64

All of the following can denature proteins without hydrolysis except

A)heat.
B)mechanical stress.
C)enzyme treatment.
D)lowering of pH.
E)heavy metal ions.

Question 65

List three denaturing agents that can act on proteins and explain how each one disrupts the protein's structure.

Question 66

Which pair of amino acids can have ionic interactions?

A)arginine and glutamic acid
B)asparagine and lysine
C)leucine and alanine
D)glutamic acid and serine
E)glycine and asparagine

Question 67

Which amino acid can form covalent sulfur-sulfur bonds?

A)cysteine
B)glycine
C)proline
D)methionine
E)phenylalanine

Question 68

When a protein is ________,its primary structure is maintained,but other aspects of its structure are disrupted.

A)denatured
B)hydrolyzed
C)ionized
D)polymerized
E)esterified

Question 69

All of the following are conjugated proteins except

A)cytochrome oxidase.
B)low-density lipoproteins.
C)myoglobin.
D)collagen.
E)casein.

Question 70

What type of forces are responsible for maintaining the quaternary structure of a protein?

A)ionic bonds
B)hydrogen bonds
C)dipole-dipole
D)hydrophobic interactions
E)all of these

Question 71

All of the following are examples of denaturing proteins except

A)souring of milk.
B)a mild sunburn.
C)using a curling iron on your hair.
D)pounding meat to tenderize it.
E)digestion of a meal.

Question 72

Which pair of amino acids can form hydrogen bonds between their R groups?

A)arginine and glutamate
B)aspartate and lysine
C)leucine and alanine
D)glutamine and serine
E)glycine and asparagine

Question 73

Protein denaturation results in a disruption of the

A)primary structure.
B)secondary and tertiary structure.
C)primary and secondary structure.
D)quaternary structure.

Question 74

Detergents would most likely disrupt what type of stabilizing interaction?

A)salt bridges
B)hydrogen bonds
C)disulfide bonds
D)hydrophobic interactions
E)hydrophilic interactions

Question 75

The quaternary structure of hemoglobin contains

A)two subunits.
B)four subunits.
C)six subunits.
D)eight subunits.

Question 76

When a glycoprotein is hydrolyzed,the products would include

A)amino acids only.
B)amino acids plus metal ions.
C)amino acids plus carbohydrates.
D)amino acids plus lipids.
E)amino acids plus RNA.

Question 77

Which pair of amino acids can have hydrophobic interactions?

A)arginine and glutamic acid
B)aspartic acid and lysine
C)leucine and alanine
D)glutamic acid and serine
E)glycine and asparagine

Question 78

The protein configuration that is primarily determined from interactions between R groups is the

A)primary structure.
B)secondary structure.
C)tertiary structure.
D)quaternary structure.
E)none of the above

Question 79

Proteins that consist of two or more chains assembled into a large 3-dimensional structure are said to display

A)primary structure.
B)secondary structure.
C)tertiary structure.
D)quaternary structure.
E)none of the above

Question 80

Which of the following processes involve protein denaturation?

A)permanent waving of hair
B)whipping cream
C)cooking egg whites
D)More than one response is correct.