Question 1

What are the products from treatment of the following peptide with trypsin?
Leu-Val-Ala-Arg-Phe-Val-Lys-Asn-Leu-Gly-Arg-Cys-Asp

Accepted Answer

A)  2 dipeptides, 1 tripeptide and 1 tetrapeptide 
B)  3 tripeptides and 1 tetrapeptide 
C)  2 tripeptides, 1 tetrapeptide and 3 free amino acids 
D)  1 dipeptide, 1 tripeptide and 2 tetrapeptides 
E)  none of these choices 
A)  2 dipeptides, 1 tripeptide and 1 tetrapeptide 
B)  3 tripeptides and 1 tetrapeptide 
C)  2 tripeptides, 1 tetrapeptide and 3 free amino acids 
D)  1 dipeptide, 1 tripeptide and 2 tetrapeptides 
E)  none of these choices D

Question 2

A technique for determining protein structure that requires crystals of the protein is ___.

Accepted Answer

A)  NMR spectroscopy 
B)  X-ray crystallography 
C)  electron crystallography 
D)  mass spectrometry 
E)  none of these choices 
A)  NMR spectroscopy 
B)  X-ray crystallography 
C)  electron crystallography 
D)  mass spectrometry 
E)  none of these choices B

Question 3

For a globular protein that is found in the cytosol, ___ would most likely be found in the proteins interior while ___ would most likely be found on the surface.

Accepted Answer

A)  Val; Phe 
B)  Leu; Ile 
C)  Leu; Ser 
D)  Thr; His 
E)  none of these choices 
A)  Val; Phe 
B)  Leu; Ile 
C)  Leu; Ser 
D)  Thr; His 
E)  none of these choices C

Question 4

The aggregated proteins seen in Alzheimer's disease and Parkinson's disease are commonly known as ___.

Accepted Answer

The answer of The aggregated proteins seen in Alzheimer's disease...

Question 5

What is the net charge of the pentapeptide Ala-Cys-Ser-Glu-Asn at pH 7?

Accepted Answer

A)  -2 
B)  -3 
C)  0 
D)  +1 
E)  none of these choices 
A)  -2 
B)  -3 
C)  0 
D)  +1 
E)  none of these choices

Question 6

Molecular chaperones assist proteins in the formation of ___.

Accepted Answer

A)  aggregates 
B)  tertiary structure 
C)  peptide bonds 
D)  primary structure 
E)  none of these choices 
A)  aggregates 
B)  tertiary structure 
C)  peptide bonds 
D)  primary structure 
E)  none of these choices

Question 7

What is the N-terminal residue of the peptide AYSDG?

Accepted Answer

A)  glutamic acid 
B)  glycine 
C)  aspartic acid 
D)  alanine 
E)  none of these choices 
A)  glutamic acid 
B)  glycine 
C)  aspartic acid 
D)  alanine 
E)  none of these choices

Question 8

Which of the following methods for cleaving a protein is properly identified?

Accepted Answer

A)  chymotrypsin: cleaves on the C-terminal side of Lys or Arg 
B)  trypsin: cleaves on the C-terminal side of Ala or Val 
C)  cyanogen bromide: cleaves on the C-terminal side of Met 
D)  elastase: cleaves on the C-terminal side of Phe, Trp or Tyr 
E)  none of these choices 
A)  chymotrypsin: cleaves on the C-terminal side of Lys or Arg 
B)  trypsin: cleaves on the C-terminal side of Ala or Val 
C)  cyanogen bromide: cleaves on the C-terminal side of Met 
D)  elastase: cleaves on the C-terminal side of Phe, Trp or Tyr 
E)  none of these choices

Question 9

At pH ___, the pentapeptide Ala-Glu-His-Val-Cys would contain two positively charged groups and one negatively charged group.

Accepted Answer

A)  1 
B)  3 
C)  5 
D)  7 
E)  9 
A)  1 
B)  3 
C)  5 
D)  7 
E)  9

Question 10

Draw the predominant structure of valine at pH 10 (pKas are 2.3 and 9.7).

Accepted Answer

Question 11

A misfolded protein can undergo ___ to attain the native structure or it can undergo ___ to become a plaque.

Accepted Answer

refolding,

Question 12

Since there are 20 standard amino acids, the number of possible linear polypeptides of length N can be expressed as ___.

Accepted Answer

A)    
B)    
C)    
D)    
E)    
A)    
B)    
C)    
D)    
E)

Question 13

Transmission spongiform encephalopathies alter ___ protein that impacts the ___ conformation of the protein resulting in aggregates.

Accepted Answer

The answer of Transmission spongiform encephalopathies alter ___ protein that...

Question 14

If an  $\alpha$ -helical region of a protein contained 18 amino acid residues, how many helical turns would be present?

Accepted Answer

A)  3.33 
B)  4 
C)  5 
D)  6 
E)  none of these choices 
A)  3.33 
B)  4 
C)  5 
D)  6 
E)  none of these choices

Question 15

Given pKa values of 2.3 and 9.7, what is the pI of alanine?

Accepted Answer

A)  12 
B)  7.4 
C)  6 
D)  4.2 
E)  none of these choices 
A)  12 
B)  7.4 
C)  6 
D)  4.2 
E)  none of these choices

Question 16

If a protein underwent a mutation such that a Glu residue was changed to another amino acid, which of the following amino acids would least likely result in a change in the overall structure of the protein?

Accepted Answer

A)  Ser 
B)  Asp 
C)  Gln 
D)  Lys 
E)  Ala 
A)  Ser 
B)  Asp 
C)  Gln 
D)  Lys 
E)  Ala

Question 17

Given pKa values of 2.1, 9.8 and 3.9 (side chain), what is the pI of aspartic acid?

Accepted Answer

A)  6.0 
B)  6.9 
C)  5.3 
D)  3.0 
E)  none of these choices 
A)  6.0 
B)  6.9 
C)  5.3 
D)  3.0 
E)  none of these choices

Question 18

What is the C-terminal amino acid in the pentapeptide Val-Leu-Arg-Ser-Gly?

Accepted Answer

A)  Val 
B)  Leu 
C)  Arg 
D)  Ser 
E)  Gly 
A)  Val 
B)  Leu 
C)  Arg 
D)  Ser 
E)  Gly

Question 19

Hemoglobin contains ___ alpha subunits and ___ beta subunits, thus making hemoglobin a ___ protein.

Accepted Answer

2, 2, hete

Question 20

The protein $\alpha$-synuclein normally forms ___ upon binding to other molecules but forms ___ that lead to amyloid deposits.

Accepted Answer

@#LAT-DLM&-helix, @#LAT-DLM&-s

Exam 4: Protein Structure

What are the products from treatment of the following peptide with trypsin? Leu-Val-Ala-Arg-Phe-Val-Lys-Asn-Leu-Gly-Arg-Cys-Asp

A technique for determining protein structure that requires crystals of the protein is ___.

For a globular protein that is found in the cytosol, ___ would most likely be found in the proteins interior while ___ would most likely be found on the surface.

The aggregated proteins seen in Alzheimer's disease and Parkinson's disease are commonly known as ___.

What is the net charge of the pentapeptide Ala-Cys-Ser-Glu-Asn at pH 7?

Molecular chaperones assist proteins in the formation of ___.

What is the N-terminal residue of the peptide AYSDG?

Which of the following methods for cleaving a protein is properly identified?

At pH ___, the pentapeptide Ala-Glu-His-Val-Cys would contain two positively charged groups and one negatively charged group.

Draw the predominant structure of valine at pH 10 (pKas are 2.3 and 9.7).

A misfolded protein can undergo ___ to attain the native structure or it can undergo ___ to become a plaque.

Since there are 20 standard amino acids, the number of possible linear polypeptides of length N can be expressed as ___.

Transmission spongiform encephalopathies alter ___ protein that impacts the ___ conformation of the protein resulting in aggregates.

If an α\alphaα -helical region of a protein contained 18 amino acid residues, how many helical turns would be present?

Given pKa values of 2.3 and 9.7, what is the pI of alanine?

If a protein underwent a mutation such that a Glu residue was changed to another amino acid, which of the following amino acids would least likely result in a change in the overall structure of the protein?

Given pKa values of 2.1, 9.8 and 3.9 (side chain), what is the pI of aspartic acid?

What is the C-terminal amino acid in the pentapeptide Val-Leu-Arg-Ser-Gly?

Hemoglobin contains ___ alpha subunits and ___ beta subunits, thus making hemoglobin a ___ protein.

The protein α\alphaα -synuclein normally forms ___ upon binding to other molecules but forms ___ that lead to amyloid deposits.

The Chemical Basis of Life

Aqueous Chemistry

Nucleic Acid Structure and Function

Protein Function

How Enzymes Work

Enzyme Kinetics and Inhibition

Lipids and Membranes

Membrane Transport

Signaling

Carbohydrates

Metabolism and Bioenergetics

Glucose Metabolism

The Citric Acid Cycle

Oxidative Phosphorylation

Photosynthesis

Lipid Metabolism

Nitrogen Metabolism

Regulation of Mammalian Fuel Metabolism

DNA Replication and Repair

Transcription and RNA

Protein Synthesis

Filters

For a globular protein that is found in the cytosol, _ would most likely be found in the proteins interior while _ would most likely be found on the surface.

Draw the predominant structure of valine at pH 10 (pK_as are 2.3 and 9.7).

A misfolded protein can undergo _ to attain the native structure or it can undergo _ to become a plaque.

Transmission spongiform encephalopathies alter _ protein that impacts the _ conformation of the protein resulting in aggregates.

If an $\alpha$ -helical region of a protein contained 18 amino acid residues, how many helical turns would be present?

Hemoglobin contains _ alpha subunits and _ beta subunits, thus making hemoglobin a ___ protein.

The protein $\alpha$ -synuclein normally forms _ upon binding to other molecules but forms _ that lead to amyloid deposits.