Deck 19: Proteins

Question 1

Which of the following terms best describes a typical protein?

A) polyester
B) polypeptide
C) acetal
D) glycoside

Answer 1

polypeptide

Question 2

Amino acids with acidic side chains contain a ____ group.

A) -COOH
B) -NH₂
C) -SH
D) -OH

Answer 2

-COOH

Question 3

A protein is hydrolyzed,and yields only amino acids as the products.What would the protein be classified as?

A) a simple protein
B) a glycoprotein
C) a lipoprotein
D) a metalloprotein

Answer 3

a simple protein

Question 4

Which of the following is not a protein?

A) enzymes
B) antibodies
C) collagen
D) All these substances are proteins.

Question 5

The isoelectric point of an amino acid is

A) the pH at which there is no net electrical charge on the amino acid.
B) the electrical charge on the amino acid in solution.
C) the electrical charge of the protein surface.
D) the pH at which there are no ions in solution.

Question 6

An amino acid that forms a solution with a pH of 3.0 as it is dissolved in distilled water has a side chain with what functional group?

A) an amino group
B) a carboxyl group
C) a hydroxyl group
D) a sulfhydryl group

Question 7

Which of the following is the best representation of an lysine in an aqueous solution at pH = 12?

A)

B)

C)

D)

Question 8

Which of the following is the functional group of amino acids that differentiates them from other acids?

A) -COOH
B) -CH=CH-
C) -NH₂
D) All of them

Question 9

The non-amino acid parts of conjugated proteins are called _____ .

A) side chains
B) prosthetic groups
C) zwitterions
D) tertiary structures

Question 10

A hormone sometimes given to induce labor is _____ .

A) prolactin
B) FSH
C) glucagon
D) oxytocin

Question 11

A large protein undergoes a hydrolysis reaction.The product(s)of such a reaction include _____ .

A) amino acids
B) glycerol
C) water
D) Large proteins do not undergo hydrolysis reactions

Question 12

An alpha amino acid contains

A) an amino group on the carbon next to the carboxylate group.
B) two amino groups.
C) two carboxyl groups.
D) an amino group on the end carbon.

Question 13

The reaction of amino acids to form 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 14

A side chain (R group)containing CH₂-OH would be classified as _____ .

A) acidic
B) basic
C) neutral and nonpolar
D) neutral and polar

Question 15

Which of the following is the best representation of the zwitterion for glycine in a neutral aqueous solution?

A)

B)

C)

D)

Question 16

Which polypeptide stimulates the production of adrenal hormones?

A) ACTH
B) ADH
C) glucagon
D) prolactin

Question 17

Which of the following structural features of amino acids is most responsible for differences in properties of proteins?

A) the carboxyl group
B) the amino group
C) the side chain (R group)
D) all are equally responsible

Question 18

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

A) right
B) left
C) bottom
D) top

Question 19

Which of the following is the best representation of glutamate in an aqueous solution at pH = 1?

A)

B)

C)

D)

Question 20

Which polypeptide decreases urine production?

A) gastrin
B) oxytocin
C) vasopressin
D) insulin

Question 21

Sickle cell anemia is a disease that results from a protein defect related to which of the following structures?

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

Question 22

The tertiary structure of myoglobin reveals that nonpolar portions are primarily on the ____ of the molecule.

A) interior
B) exterior
C) iron containing portion
D) oxygen containing portion

Question 23

The sequence of amino acids in a protein is called the ____ structure.

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

Question 24

Foreign substances that stimulate an immune response are called _____ .

A) antigens
B) antibodies
C) immunoglobolins
D) lymphocytes

Question 25

What type of interaction forms when two nonpolar side chains are in close proximity?

A) disulfide bridge
B) hydrogen bond
C) hydrophilic interaction
D) hydrophobic interaction

Question 26

The major difference between normal hemoglobin and that of sickle cell anemia is

A) sickle cell hemoglobin is the L isomer and the normal is the D isomer.
B) sickle cell hemoglobin is a much smaller molecule than normal hemoglobin.
C) sickle cell hemoglobin is assembled in a reverse manner.
D) sickle cell hemoglobin has one different amino acid in each $\beta$ -chain.

Question 27

A pleated sheet structure is an example of ____ protein structure.

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

Question 28

Protein denaturation results in a disruption of the

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

Question 29

The association of several protein chains into a larger structure as in the case of hemoglobin is an example of ____ structure.

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

Question 30

Which protein is an important component of hair and feathers?

A) myosin
B) amylase
C) ( $\alpha$ -keratin)
D) fibrinogen

Question 31

Which of the following proteins is an example of a glycoprotein?

A) casein
B) fibrin
C) gamma globulin
D) myoglobin

Question 32

Which of the following is the best representation of a segment of a protein chain?

A)

B)

C)

D)

Question 33

Some proteins owe their functions to the three dimensional shape they have;what is responsible for holding the shape of a protein?

A) occurs spontaneously and remains constant
B) the length of the protein
C) R-group interactions
D) is established on the basis of the hydrophobic and hydrophilic forces that develop

Question 34

What type of interaction forms when two side chains containing an amino group and a carboxyl group are in close proximity?

A) disulfide bridge
B) salt bridge
C) hydrogen bond
D) hydrophobic interactions

Question 35

$\alpha$ -Keratin,the protein of hair and skin,has extensive sections with the ____ secondary structure.

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

Question 36

What bonding forces are responsible for the secondary structure of a protein?

A) disulfide linkages
B) salt bonds
C) hydrophobic bonding
D) hydrogen bonding

Question 37

Glycoproteins are a combination of protein and _____ .

A) lipids
B) carbohydrates
C) nucleic acids
D) steroids

Question 38

The protein responsible for the mechanical strength of skin in mammals is?

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

Question 39

Cross links between peptide chains resulting from interactions of the side chains contribute to which type of protein structural feature?

A) primary
B) secondary
C) tertiary
D) more than one response is correct

Question 40

The structure of human insulin

A) includes disulfide bridges averaging every 6 amino acid pairs.
B) includes both an alpha and a beta helix.
C) is characterized by being a large molecule with a complex three-dimensional structure.
D) None of the above.

Question 41

The figure below shows a portion of what type of secondary protein structure?

A) alpha helix
B) beta sheet
C) neither a or b
D) insufficient information

Question 42

The following peptide could be named as _____ .

A) valinylphenylalanyl
B) alanylphenylvaline
C) glycylphenylleucine
D) glycylphenylalanine

Question 43

Which of the following would not denature an egg?

A) heat
B) strong acid
C) water
D) UV light

Question 44

Hemoglobin consists of several components,including which of the following?

A) heme groups
B) alpha chains
C) beta chains
D) More than one answer is correct.

Question 45

Which of the following is a function of proteins?

A) catalytic
B) protective
C) storage
D) all of these

Question 46

Which of the following best classifies the side chain of the amino acid listed below?

A) neutral,nonpolar
B) basic,polar
C) neutral,polar
D) acidic,polar

Question 47

How many peptide bonds are in the following structural formula?

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

Question 48

Which of the following is the structure for tryptophan?

A)

B)

C)

D)

Question 49

A denatured protein

A) has undergone a process which changes the D isomer to an L isomer.
B) has the same shape but lacks all cross links.
C) does not have the function it previously had.
D) is a stereoisomer of the original form..

Question 50

If the following compound were completely hydrolyzed,how many amino acids could be produced?

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

Question 51

A nursing mother comes to you wanting to take something for minor arthritis pain.Which drug would you not recommend her to use?

A) Acetaminophen
B) Ibuprofen
C) Codeine
D) Methotrexate

Question 52

Although the common amino acids all have accepted standard names,they can also be named using the IUPAC organic chemical nomenclature system.Below is the structure for the simplest amino acid,glycine.What would be its IUPAC name?

A) 1-hydroxy-2-aminoethanone
B) 1-carboxy-2-amoinoethanol
C) 2-carboxy-2-hydroxyethanamine
D) 2-aminoethanoic acid

Question 53

Proteins can be classified based on _____ .

A) function.
B) shape.
C) composition.
D) all of these

Question 54

The figure below shows a portion of what type of secondary protein structure?

A) alpha helix
B) beta sheet
C) neither a or b
D) insufficient information

Question 55

Tertiary structures of proteins result from R-group interactions.Which of the following is not a R-group interaction?

A) salt bridges
B) hydrogen bonds
C) disodium bridges
D) hydrophobic interactions

Question 56

Consider the tertiary structure of a protein containing two peptides with the segments shown below.What type(s)of interaction(s)would be possible between the side chains?

A) hydrogen bonding
B) hydrophobic interactions
C) salt bridges
D) all of the above

Question 57

Which of the following is the structure for alanine?

A)

B)

C)

D)

Question 58

Using the three-letter abbreviations for amino acids,following peptide would be _____ .

A) Ala-Phe-Leu
B) Leu-Phe-Ala
C) Ala-Phe-Val
D) Gly-Phe-Ile

Question 59

What is the name of the following amino acid?

A) alanine
B) tyrosine
C) phenylalanine
D) proline

Question 60

How many different tripeptides could be formed by 1 of each of the following amino acids?
[ lysine histidine aspartate ]

A) 1
B) 3
C) 6
D) 9

Question 61

The peptide linkage is an amide bond.

Question 62

Denaturation usually involves a change in the primary structure of the protein.

Question 63

It is considered important to suppress ones appetite when dieting.Which nutrient is considered as having the greatest ability to satisfy hunger?

A) fats
B) carbohydrates
C) protein
D) vitamins

Question 64

If a protein is made up of primarily of long,rod-shaped or string-like structures,it would be considered a ____ protein.

A) conjugated
B) globular
C) fibrous
D) enzymatic

Question 65

Proteins can be produced by using any one of the naturally occurring amino acids.

Question 66

A zwitterion is dipolar;it possesses a positive end and a negative end.

Question 67

Whipping of egg white involves protein denaturation.

Question 68

A protein important in blood clotting is keratin.

Question 69

The biologically important peptides are formed from alpha amino acids.

Question 70

An ion which is especially effective at causing protein denaturation is Hg²⁺.

Question 71

A major characteristic of the alpha amino acids is that they all possess polar side chains;the beta amino acids do not possess side chains.

Question 72

Of the many sulfur-containing amino acids,cysteine is the only one that can not form disulfide bridges.

Question 73

Nursing mothers should not take medications just before breast feeding.

Question 74

The digestion of peptides is an oxidation reaction.

Question 75

Peptide bonds usually are not cleaved in denaturation.

Question 76

When proteins are hydrolyzed,amide bonds are cleaved.

Question 77

Ferritin functions as an iron storage protein.

Question 78

Denaturation is usually easily reversible.

Question 79

The quaternary structure of hemoglobin contains two subunits.

Question 80

The formation of a disulfide bond between two cysteine molecules requires oxidation.