Deck 14: Proteins

Question 1

Glycogen phosphorylase breaks down glycogen in the liver to produce glucose-1-phosphate. The activity of this enzyme increases in the presence of AMP. AMP is therefore a negative effector in controlling this pathway.

Answer 1

False

Question 2

The following representation accurately depicts the structure of a peptide group.

Answer 2

False

Question 3

Enzymes are sensitive to agitation and will be denatured by violent stirring.

Answer 3

True

Question 4

The amino acid shown below maybe associated with ALS (Lou Gehrig's disease) and Parkinson's disease. The side chain of this amino acid listed below would be classified as:

A) hydrophilic
B) hydrophobic
C) acidic
D) basic
E) a and c
F) a and d

Question 5

When the term "essential" is applied to a substance, this means that it cannot be synthesized by an organism and must be obtained from dietary sources.

Question 6

Nonessential amino acids are those which can be synthesized by the body.

Question 7

The secondary structure of proteins is stabilized by covalent bonds.

Question 8

If an amino acid contained the following side chain would be classified as hydrophobic.

Question 9

Consider the two "peptides" shown below. Ala-Gly-Phe-Phe-Ala-Gly-Val
Val-Leu-Iso-Ala-Gly-Val-Phe
The side chains of these two "peptides" could form hydrophilic interactions with one another.

Question 10

How many different amino acids are commonly found in proteins?

A) 10
B) 20
C) 200
D) 1000

Question 11

An alpha amino acid contains

A) an amine group on the carbon next to the carboxylic acid group.
B) two amine groups.
C) two carboxylic acid groups.
D) an amine group on the end carbon.

Question 12

An amino acid can be correctly characterized as:

Question 13

The following amino acid would be found in the interior of a protein.

Question 14

Which of the following contains a sulfur atom as part of the side chain?

A) cysteine
B) glycine
C) proline
D) tryptophan

Question 15

Pyruvate dehydrogenase contains a Mg²⁺ ion. The magnesium ion is called a coenzyme.

Question 16

Albumin is a protein found in blood.

Question 17

Both isoleucine and alanine can be synthesized from other nutrients.

Question 18

The following is an example of a secondary protein structure.

Question 19

During the urea cycle, nitrogen is removed from amino acids and subsequently converted it to urea.

Question 20

Consider a protein at 25 °C which is heated to 48 °C then cooled back to 25 °C. The following shows schematically the protein structure at these three temperatures, respectively. 25 °C 48 °C 25 °C
Based on this information, the enzyme activity will return at the final temperature (25 °C).

Question 21

The following represents the nitrogen cycle. Which of the choices correctly pairs the lettered reactions with the type of organism?

A) A - bacteria B - animals
C - plants
B) A - plants B - animals
C - bacteria
C) A - plants B - bacteria
C - animals
D) A - animals B - bacteria
C - plants

Question 22

What class of protein is represented by the following?

A) fibrous
B) globular
C) membrane
D) either fibrous or membrane

Question 23

Consider the level of protein structure that forms when the two polypeptides shown below interact. Which type of side chain interaction is particularly important in forming this level of structure?

A) ion pair
B) disulfide bridge
C) hydrophobic interaction
D) hydrophilic interaction

Question 24

The amino acid shown below maybe associated with ALS (Lou Gehrig's disease) and Parkinson's disease. Which of the following is the form of this amino acid at a physiological pH?

A)
B)
C)
D)
E) None of these

Question 25

What type of interaction would occur between the side chains of the two amino acids shown below?

A) ion-ion attraction
B) disulfide bridge
C) hydrophobic interaction
D) hydrophilic interaction

Question 26

What type of interaction would occur between the side chains of two molecules of the amino acid shown below?

A) ion pair
B) disulfide bridge
C) hydrophobic interaction
D) hydrophilic interaction

Question 27

Total nitrogen in the diet must provide enough nitrogen for the synthesis of

A) essential amino acids.
B) nonessential amino acids.
C) nonessential amino acids and any other synthesized nitrogen-containing compounds.
D) essential amino acids and any other synthesized nitrogen-containing compounds.

Question 28

The following represents the results of an experiment on a metabolic enzyme. What is the optimum pH of this enzyme?

A) 3.0
B) 5.5
C) 6.5
D) 9.5

Question 29

The addition of a 0.10 M solution of Mg(NO₃)₂ would most likely affect which type of interaction in the tertiary structure of a protein?

A) hydrogen bonding
B) hydrophobic interactions
C) hydrophilic interactions
D) ion-ion attractions

Question 30

Addition of 0.050 M NaOH to a protein solution would have the most profound effect on which of the listed amino acids?

A) phenylalanine
B) serine
C) methionine
D) aspartic acid

Question 31

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 32

Consider the tertiary structure of a protein containing two peptides with the segments shown below. What types of interactions would be possible?

A) hydrogen bonding
B) hydrophobic interactions
C) ion-ion attractions
D) all of the above

Question 33

Which of the following must be supplied by the diet?

A) essential amino acids
B) iron
C) zinc
D) All must be part of the diet.

Question 34

Which of the following is the form that human body uses to excrete nitrogen?

A) nitrate ion
B) urea
C) ammonium ion
D) molecular nitrogen

Question 35

How many chiral carbon atoms are present in the amino acid shown below?

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

Question 36

Consider the following description of an area of current research. "Beta-polypeptides are polymers of beta amino acids with backbones one carbon longer than alpha-polypetptides. Like the alpha-polypeptides found in nature, beta-polypeptides can form stable helices and pleated sheets." Which levels of protein structure are cited in this statement?

A) primary
B) secondary
C) tertiary
D) quaternary
E) primary and secondary
F) primary, secondary, and tertiary
G) primary, secondary, tertiary, and quaternary

Question 37

Which of the following levels of protein structure can involve covalent bond formation?

A) primary
B) secondary
C) tertiary
D) quaternary
E) primary and tertiary
F) primary, tertiary and quaternary

Question 38

What is the three-letter representation for the peptide given below?

A) Ala-Ser-Ala-Gly-Gly
B) Gly-Gly-Ala-Ser-Ala
C) Gly-Ala-Ser
D) Gly-Ala-Ser-Ala

Question 39

The amino acid shown below maybe associated with ALS (Lou Gehrig's disease) and Parkinson's disease. Which of the following is the zwitterion ion form of the uncommon amino acid?

A)
B)
C)
D)

Question 40

Which of the following statements does not characterize coenyzmes?

A) non-amino acid composition
B) structure is organic in composition
C) do not bind permanently to the enzyme
D) all of these characterize coenzymes

Question 41

Consider the structure shown below. Fill in the blanks with an integer (1, 2, 3, 4, 5....) as shown in the diagram or to represent a specified number.
The atom represented by the number _______________________ would carry a δ- charge.

Question 42

Consider the structure shown below. Fill in the blanks with an integer (1, 2, 3, 4, 5....) as shown in the diagram or to represent a specified number.
The N-terminal group is represented by the number___________________,

Question 43

The reaction given below would be classifed as:

A) oxidative decarboxylation.
B) transamination.
C) oxidative deamination.
D) nitrogen fixation

Question 44

Which type of protein has the most compact structure?

A) globular
B) fibrous
C) membrane

Question 45

This image could represent the reaction in which lactase catalyzes the hydrolysis of lactose (a disaccharide) into glucose and galactose (two monosaccharides). Fill in the blanks with the appropriate letter (A, B, C, D,....) from the image.
The enzyme-substrate complex is represented by __________________.

Question 46

This image could represent the reaction in which lactase catalyzes the hydrolysis of lactose (a disaccharide) into glucose and galactose (two monosaccharides). Fill in the blanks with the appropriate letter (A, B, C, D,....) from the image.
A competitive inhibitor would resemble _____________________.

Question 47

This image could represent the reaction in which lactase catalyzes the hydrolysis of lactose (a disaccharide) into glucose and galactose (two monosaccharides). Fill in the blanks with the appropriate letter (A, B, C, D,....) from the image.
___________________ represents lactase.

Question 48

This image could represent the reaction in which lactase catalyzes the hydrolysis of lactose (a disaccharide) into glucose and galactose (two monosaccharides). Fill in the blanks with the appropriate letter (A, B, C, D,....) from the image.
Galactose could be represented by __________________.

Question 49

An enzyme found in the blood would be expected to have maximum activity at a pH

A) slightly above 7.
B) slightly below 7.
C) of 7.

Question 50

Consider the amino acid sequence given below. Gly-Ala-Thr-Cys Ala would be considered

A) neither C-terminal or N-terminal.
B) C-terminal.
C) N-terminal.

Question 51

Consider the following representation of an enzyme-catalyzed reaction.
The reactants, water and lactose, are represented in the image by __________________ and _________________.

Question 52

Consider the following image. The " ? " in the image represents

A) negative effector.
B) competition inhibitor.
C) positive effector.
D) denaturing agent.

Question 53

Consider the structure shown below. Fill in the blanks with an integer (1, 2, 3, 4, 5....) as shown in the diagram or to represent a specified number.
A hydrophilic side chain is indicated by the number__________________.

Question 54

The reaction in the breakdown of amino acids that involves the removal of nitrogen is

A) oxidative decarboxylation.
B) transamination.
C) oxidative deamination.
D) nitrogen fixation

Question 55

Consider the structure shown below. Fill in the blanks with an integer (1, 2, 3, 4, 5....) as shown in the diagram or to represent a specified number.
The free carboxylate group is represented by the number _____________________.

Question 56

The ultimate fate of the nitrogen from the metabolism of amino acids in mammals is:

A) excretion as NH₄⁺.
B) incorporation into intermediates in the citric acid cycle.
C) removal as urea in the kidneys.
D) used to fuel ATP producing reactions.

Question 57

Consider the structure shown below. Fill in the blanks with an integer (1, 2, 3, 4, 5....) as shown in the diagram or to represent a specified number.
This structure contains _______________________ peptide groups.

Question 58

This image could represent the reaction in which lactase catalyzes the hydrolysis of lactose (a disaccharide) into glucose and galactose (two monosaccharides). Fill in the blanks with the appropriate letter (A, B, C, D,....) from the image.
The active site of the enzyme is represented by ___________________.

Question 59

Consider the structure shown below. Fill in the blanks with an integer (1, 2, 3, 4, 5....) as shown in the diagram or to represent a specified number.
The backbone contains ______________________ amino acids.

Question 60

Consider the structure shown below. Fill in the blanks with an integer (1, 2, 3, 4, 5....) as shown in the diagram or to represent a specified number.
The atom represented by the number ____________________ could act as a proton acceptor in the hydrogen bonding present in an alpha helix.

Question 61

This image could represent the reaction in which lactase catalyzes the hydrolysis of lactose (a disaccharide) into glucose and galactose (two monosaccharides). Fill in the blanks with the appropriate letter (A, B, C, D,....) from the image.
An effector would bind at ______________________.

Question 62

A month after Micah's fourth birthday, his mother notices that Micah's eyes seem puffy and his ankles look swollen. Over the next couple of weeks, Micah's feet and ankles continue to swell and he seems to be short on energy, so his mother takes him to the local clinic. The nurse practitioner orders several lab tests, including a measurement of the concentration of albumin in Micah's blood and urine.
a.) Is it normal to exhibit increasing puffiness, also known as edema, around the eyes, ankles, and feet? Why or why not?
b.) Micah's urine test results showed significant amounts of albumin. Why would this be of concern?
c.) Given Micah's significant amount of proteinuria/albuminuria, why would his serum blood level of albumin be significantly lower than usual?

Question 63

Draw the structure of a tripeptide that has a C-terminal alanine, an N-terminal serine and an leucine. Indicate the backbone in the structure.

Question 64

Draw the zwitterion ion form of phenylalanine.

Question 65

Draw two ways serine can hydrogen bond with water.

Question 66

Is it possible for a person who consumes substantial amounts of protein in their diet to suffer from protein deficiency? Explain.

Question 67

Lysine is a weak acid under physiological conditions but it is classified as a basic amino acid. Briefly explain.