Deck 10: Proteins - Workers of the Cell

Question 1

Which of the following amino acids is an essential amino acid in the diets of children but not adults?

A)Arginine
B)Lysine
C)Aspartate
D)Glycine

Answer 1

Arginine

Question 2

How many amino acids are essential in humans?

A)5
B)10
C)18
D)20

Answer 2

10

Question 3

What type of amino acid is phenylalanine?

A)Polar neutral
B)Nonpolar neutral
C)Acidic
D)Basic

Answer 3

Nonpolar neutral

Question 4

What type of amino acid is tyrosine?

A)Polar neutral
B)Nonpolar neutral
C)Acidic
D)Basic

Question 5

What type of amino acid is glutamic acid?

A)Polar neutral
B)Nonpolar neutral
C)Acidic
D)Basic

Question 6

What type of amino acid is histidine?

A)Polar neutral
B)Nonpolar neutral
C)Acidic
D)Basic

Question 7

What are the three letter and one letter designation for tyrosine?

A)Tyr, Y
B)Trp, W
C)Thr, T
D)Tyr, H

Question 8

What are the three letter and one letter designation for asparagine?

A)Asp, D
B)Asp, N
C)Asn, N
D)Asn, P

Question 9

What are the three letter and one letter designation for aspartate?

A)Asp, D
B)Asp, N
C)Asn, N
D)Asn, P

Question 10

Which of the following amino acids contains sulfur in the side chain?

A)Phenylalanine
B)Cysteine
C)Tyrosine
D)Glycine

Question 11

Which of the following amino acids contains an aromatic ring in the side chain?

A)Tryptophan
B)Serine
C)Proline
D)Glutamine

Question 12

All amino acids contain a chiral carbon except for one. Which one?

A)Phenylalanine
B)Cysteine
C)Glycine
D)Histidine

Question 13

Which of the following amino acids is classified as being hydrophobic?

A)Histidine
B)Cysteine
C)Arginine
D)Phenylalanine

Question 14

Which of the following amino acids is classified as being hydrophilic?

A)Leucine
B)Aspartate
C)Valine
D)Proline

Question 15

Which list contains only nonpolar amino acids?

A)Gly, Leu, Ile, Phe
B)Ser, Thr, Gln, Asn
C)Asp, Glu, His, Arg
D)Gly, Ile, Gln, Glu

Question 16

Which list contains only neutral polar amino acids?

A)Ser, Cys, Phe, Glu
B)Asn, Gln, Cys, Tyr
C)Cys, Asn, His, Arg
D)Lys, Glu, Thr, Tyr

Question 17

Which list contains only essential amino acids?

A)Pro, Met, Val, Leu
B)Thr, Glu, His, Lys
C)His, Lys, Trp, Ile
D)Ala, Val, Phe, Met

Question 18

An essential amino acid is defined as one that:

A)occurs in human protein
B)occurs in all animal protein
C)must be part of the proteins of the food supply of humans
D)is capable of being synthesized within the human body

Question 19

Corn is an incomplete protein because it lacks one or more:

A)amino acids
B)amino acids containing sulfur
C)free amino acids
D)essential amino acids

Question 20

Which is not a characteristic element of proteins?

A)Cl
B)C
C)H
D)N

Question 21

This dipeptide is designated as:

A)Ser-Lys
B)Ser-Cys
C)Cys-Ser
D)Lys-Ser

Question 22

Which amino acid is the N-terminal group in the following peptide?
Gly-Ala-Val-Phe-Tyr

A)Gly
B)Ala
C)Val
D)Tyr

Question 23

The structure among the following that represents an amide (protein)bond is:

A)
B)
C)
D)

Question 24

Which amino acid is the C-terminal group in the following peptide?
Gly-Ala-Val-Phe-Tyr

A)Gly
B)Ala
C)Val
D)Tyr

Question 25

What amino acids are involved in the following tripeptide?

A)Lys-His-Phe
B)Lys-His-Tyr
C)His-Lys-Phe
D)Tyr-His-Lys

Question 26

The sequence of amino acids is considered to be the ________ structure of a protein.

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

Question 27

The pattern the backbone folds, for example alpha-helix or beta pleated sheet, is the ________ structure of a protein.

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

Question 28

The interaction of the side chains on the amino acids, for example hydrophobic attractions, is the ________ structure of a protein.

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

Question 29

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

A)Peptide bonds
B)Hydrogen bonding between the carbonyl group and amino group
C)Salt bridges
D)Dipole-dipole

Question 30

Which type of forces stabilizes the secondary structure of a protein?

A)Peptide bonds
B)Hydrogen bonding between the carbonyl group and amino group
C)Salt bridges
D)Dipole-dipole

Question 31

Which pair of amino acids can have nonpolar (hydrophobic)interactions?

A)Arginine and glutamate
B)Phenylalanine and valine
C)Cysteine and cysteine
D)Tyrosine and serine

Question 32

What type of stabilizing interaction could there be between the side chains of glutamic acid and lysine?

A)Disulfide bonds
B)Hydrogen bonds
C)Hydrophobic interactions
D)Salt bridges

Question 33

What type of stabilizing interaction could there be between the side chains of two cysteine amino acids?

A)Disulfide bonds
B)Hydrogen bonds
C)Hydrophobic interactions
D)Salt bridges

Question 34

What type of stabilizing interaction could there be between the side chains of serine and threonine?

A)Disulfide bonds
B)Hydrogen bonds
C)Hydrophobic interactions
D)Salt bridges

Question 35

What type of stabilizing interaction would be expected between phenylalanine and valine?

A)Salt bridges
B)Hydrogen bonds
C)Disulfide bonds
D)Hydrophobic interaction

Question 36

Identify the amino acid that would only involve hydrophobic interactions in the tertiary structure of a protein.

A)
B)
C)
D)

Question 37

Identify the amino acid that could form salt bridge interactions in the tertiary structure of a protein.

A)
B)
C)
D)

Question 38

The alpha-helix is an example of:

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

Question 39

What type of interaction is involved in the tertiary structure of a protein?

A)Hydrogen bonding
B)Salt bridges
C)Disulfide bonds
D)All of the above

Question 40

Which of the following is an example of globular protein?

A)Keratins
B)Collagen
C)Myoglobin
D)Skin

Question 41

Which of the following is an example of a fibrous protein?

A)Collagen
B)Myoglobin
C)Hemoglobin
D)Albumin

Question 42

A protein that is comprised of two or more protein chains that interact to make the overall structure is called the:

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

Question 43

Heavy metals such as Pb²⁺ or Hg²⁺ denature proteins by reacting with:

A)the proline residues
B)the OH group of tyrosine residues
C)the SH group of cysteine residues
D)the NH₂ group of glutamine

Question 44

Detergents would most likely disrupt what type of stabilizing interaction?

A)Salt bridges
B)Hydrogen bonds
C)Disulfide bonds
D)Hydrophobic interaction

Question 45

Each of the following can cause a protein to denature except:

A)heat
B)detergents
C)enzyme treatment
D)change in pH

Question 46

Which of the following is an example of a transport protein?

A)Hemoglobin
B)Collagen
C)Pepsin
D)Oxytocin

Question 47

Which of the following proteins has a distinctive Y-shape?

A)Hemoglobin
B)Collagen
C)Antibodies
D)Integral protein

Question 48

Which of the following proteins has a roughly spherical structure?

A)Hemoglobin
B)Collagen
C)Antibodies
D)Integral protein

Question 49

The area on the enzyme that interacts with the substrate is called the:

A)regulatory site
B)modulator site
C)active site
D)allosteric site

Question 50

Some enzyme requires a nonprotein organic component in order to have full activity. This nonprotein component is called a:

A)cofactor
B)coenzyme
C)regulator
D)substrate

Question 51

An inorganic substance that assists in an enzyme catalytic process is called a:

A)cofactor
B)coenzyme
C)regulator
D)substrate

Question 52

What is the primary function of enzymes?

A)Neurotransmitters
B)Biochemical catalysts
C)Structure
D)Transport

Question 53

Enzymes function as a catalyst by:

A)lowering the overall energy change in a reaction
B)changing the equilibrium constant
C)increasing the time it takes for a reaction to take place
D)lowering the activation energy of a reaction

Question 54

Some enzymes require certain metal ions, such as Mg²⁺ or Zn²⁺, in order to have full activity. This component is called a:

A)cofactor
B)coenzyme
C)regulator
D)substrate

Question 55

An enzyme will increase the rate of certain reactions with certain substances. This characteristic is called:

A)selectivity
B)specificity
C)regulation
D)inhibition

Question 56

The model that explains that the substrate fits exactly into the active site of an enzyme is called:

A)induced fit
B)lock and key
C)substrate selectivity
D)coenzyme

Question 57

The model that explains that the active site of an enzyme is flexible and will mold to the shape of the substrate is called:

A)induced fit
B)lock and key
C)substrate selectivity
D)coenzyme

Question 58

What factors can influence the speed of a reaction by an enzyme?

A)The orientation of the reactants
B)The weakening of bond energies in the reactants
C)The closeness of the reactants to each other in the active site
D)All of the above

Question 59

A molecule that is similar in terms of the correct structure to the substrate for an enzyme will probably be a:

A)cofactor
B)regulator
C)competitive inhibitor
D)noncompetitive inhibitor

Question 60

The process of competitive inhibition can be overcome by:

A)increasing the pH
B)increasing the substrate concentration
C)decreasing the temperature
D)all of the above

Question 61

The pH of the environment in which an enzyme is located can influence the reactivity because a change in pH:

A)can hydrolyze the protein
B)can produce protonation or deprotonation of residues in the active site
C)changes the primary structure
D)affects the optical activity

Question 62

Heavy metals such as Pb²⁺ or Hg²⁺ act as a(n)________ inhibitor.

A)irreversible
B)reversible
C)noncompetitive
D)competitive

Question 63

When a molecule binds to an enzyme at a site other than the active site and affects enzyme shape it is called a(n):

A)noncompetitive inhibitor
B)competitive inhibitor
C)irreversible inhibitor
D)covalent modification

Question 64

The point at which an enzyme reacts at its maximum activity is called a:

A)pH dependence
B)steady state
C)saturation point
D)reaction maximum

Question 65

The optimum pH for an enzyme such as pepsin that works to break down peptide bonds would be:

A)acidic
B)basic
C)neutral
D)all of the above

Question 66

The optimum pH for an enzyme such as hexokinase that phosphorylates glucose in the blood would be:

A)2)0
B)7)5
C)9)0
D)none of these

Question 67

The optimum pH for an enzyme such as arginase that acts on arginine in the liver would be:

A)2)0
B)7)5
C)9)7
D)none of these

Question 68

Increasing the temperature of an enzyme will:

A)denature it
B)make the reaction rate increase
C)slow down the reaction
D)have no effect on the enzyme's activity

Question 69

A reversible inhibitor is one that:

A)binds permanently to the enzyme
B)binds temporarily to the enzyme
C)denatures the enzyme
D)activates the enzyme

Question 70

Penicillin is an example of a(n):

A)irreversible inhibitor
B)reversible inhibitor
C)activator
D)noncompetitive inhibitor

Question 71

The use of ethanol to combat methanol poisoning in humans is an example of a(n):

A)irreversible inhibitor
B)competitive inhibitor
C)activator
D)noncompetitive inhibitor

Question 72

What distinguishes an essential amino acid from the other amino acids?

Question 73

Arginine is one of two amino acids that are essential in the diets of children but not adults. Which is the other one?

Question 74

Write the three-letter and one-letter abbreviations for the basic polar amino acids, histidine, lysine and arginine.

Question 75

Write the three-letter codes for the three amino acids that have an aromatic ring in the sidechain.

Question 76

Draw the structure of the amino acid threonine. What type of amino acid is it?

Question 77

Draw the structure of the amino acid phenylalanine. What type of amino acid is it?

Question 78

Draw an amide bond.

Question 79

The formation of an amide group from an amine and a carboxylic acid involves a ________ reaction.

Question 80

When an amide bond is formed between two amino acids, what other molecule is produced?