Deck 19: Proteins

Question 1

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

Answer 1

-NH₂

Question 2

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

Answer 2

a carboxyl group

Question 3

A hormone sometimes given to induce labor is _____ .

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

Answer 3

oxytocin

Question 4

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 5

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

Question 6

Which of the following terms best describes a typical protein?

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

Question 7

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

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

Question 8

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

A)
B)
C)
D)

Question 9

Amino acids with acidic side chains contain a ____ group.

A)- COOH
B)- NH₂
C)- SH
D)- OH

Question 10

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

A)
B)
C)
D)

Question 11

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 12

Which of the following is not a protein?

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

Question 13

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

A)
B)
C)
D)

Question 14

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 15

Which polypeptide stimulates the production of adrenal hormones?

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

Question 16

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 17

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 18

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 19

Which polypeptide decreases urine production?

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

Question 20

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 21

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 β -chain.

Question 22

Glycoproteins are a combination of protein and _____ .

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

Question 23

Which protein is an important component of hair and feathers?

A)myosin
B)amylase
C)α -keratin
D)fibrinogen

Question 24

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 25

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 26

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

A)
B)
C)
D)

Question 27

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 these

Question 28

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

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

Question 29

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

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

Question 30

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 31

Foreign substances that stimulate an immune response are called _____ .

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

Question 32

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 33

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 34

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 35

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 36

α -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 37

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 38

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

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

Question 39

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 40

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

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

Question 41

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 42

What is the name of the following amino acid?  

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

Question 43

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 44

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 45

How many peptide bonds are in the following structural formula?

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

Question 46

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 47

Which of the following is a function of proteins?

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

Question 48

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 these

Question 49

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 50

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 51

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 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

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 54

The following peptide could be named as _____ .

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

Question 55

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

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

Question 56

Proteins can be classified based on _____ .

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

Question 57

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 58

Which of the following would not denature an egg?

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

Question 59

Which of the following is the structure for alanine?

A)
B)
C)
D)

Question 60

Which of the following is the structure for tryptophan?

A)
B)
C)
D)

Question 61

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

Question 62

Ferritin functions as an iron storage protein.

Question 63

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

Question 64

Nursing mothers should not take medications just before breast feeding.

Question 65

Peptide bonds usually are not cleaved in denaturation.

Question 66

The digestion of peptides is an oxidation reaction.

Question 67

A protein important in blood clotting is keratin.

Question 68

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 69

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

Question 70

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

Question 71

The biologically important peptides are formed from alpha amino acids.

Question 72

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 73

Whipping of egg white involves protein denaturation.

Question 74

When proteins are hydrolyzed, amide bonds are cleaved.

Question 75

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

Question 76

The peptide linkage is an amide bond.

Question 77

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 78

The quaternary structure of hemoglobin contains two subunits.

Question 79

Denaturation is usually easily reversible.

Question 80

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