Question 1

Which component is involved with hydrogen bonding of the carbonyl oxygen in a b-turn of peptide chain?

Accepted Answer

A) the amide proton on the next amino acid down the chain 
B) the amide proton of the glutamine side chain 
C) the amide proton of the residue 3 positions down the chain 
D) the amide proton of the asparagine side chain 
A) the amide proton on the next amino acid down the chain 
B) the amide proton of the glutamine side chain 
C) the amide proton of the residue 3 positions down the chain 
D) the amide proton of the asparagine side chain C

Question 2

Which combination of atoms forms the resonance structure within the "amide plane"?

Accepted Answer

A) CαH-NH-CO-C-CαH 
B) CαH-NH-CO 
C) Cα-NH-CO-Cα 
D) NH-CO-Cα 
A) CαH-NH-CO-C-CαH 
B) CαH-NH-CO 
C) Cα-NH-CO-Cα 
D) NH-CO-Cα C

Question 3

Which of the following is a feature of antiparallel b-sheets?

Accepted Answer

A) They progress from N- to C-termini in the same direction. 
B) Usually all their hydrophobic residues are on one side of the sheet. 
C) They consist of all hydrophobic residues. 
D) The fibres can be stretched or extended,but are not flexible. 
A) They progress from N- to C-termini in the same direction. 
B) Usually all their hydrophobic residues are on one side of the sheet. 
C) They consist of all hydrophobic residues. 
D) The fibres can be stretched or extended,but are not flexible. B

Question 4

Which characteristic of a peptide contains all the information necessary for folding the peptide chain into its "native" structure?

Accepted Answer

A) its amino acid sequence 
B) its amino acid composition 
C) its configuration 
D) its amino acid side chain charges 
A) its amino acid sequence 
B) its amino acid composition 
C) its configuration 
D) its amino acid side chain charges

Question 5

Which of the following is NOT a class of globular proteins according to type and arrangement of secondary structure?

Accepted Answer

A) small metal- and disulfide-rich proteins 
B) parallel or mixed β-sheets 
C) antiparallel β-sheets 
D) antiparallel β-turns 
A) small metal- and disulfide-rich proteins 
B) parallel or mixed β-sheets 
C) antiparallel β-sheets 
D) antiparallel β-turns

Question 6

What is the "Greek key" topology composed of?

Accepted Answer

A) adjacent a-helices oriented in the opposite direction 
B) discreet regions of β-sheet oriented in an antiparallel fashion 
C) discreet regions of β-turns 
D) parallel β-sheet structures connected by a-helices 
A) adjacent a-helices oriented in the opposite direction 
B) discreet regions of β-sheet oriented in an antiparallel fashion 
C) discreet regions of β-turns 
D) parallel β-sheet structures connected by a-helices

Question 7

Silk fibres consist of fibroin proteins that are comprised of which alternating amino acid residues?

Accepted Answer

A) glycine;alanine;serine 
B) glycine;proline;leucine 
C) alanine;glycine;serine 
D) glycine;alanine;threonine 
A) glycine;alanine;serine 
B) glycine;proline;leucine 
C) alanine;glycine;serine 
D) glycine;alanine;threonine

Question 8

Which statement is NOT correct regarding the tertiary structure of the enzyme triose phosphate isomerase?

Accepted Answer

A) Its β-strands are parallel. 
B) Its α-helices are in the interior of the molecular structure. 
C) It contains a β-barrel in the centre of its structure. 
D) It is composed entirely of alternating α-helices and β-strands. 
A) Its β-strands are parallel. 
B) Its α-helices are in the interior of the molecular structure. 
C) It contains a β-barrel in the centre of its structure. 
D) It is composed entirely of alternating α-helices and β-strands.

Question 9

Which 2 amino acids act as helix breakers due to their unique structure,which fixes the value of the Cα-N-C bond angle?

Accepted Answer

A) histidine and lysine 
B) proline and hydroxyproline 
C) arginine and lysine 
D) serine and threonine 
A) histidine and lysine 
B) proline and hydroxyproline 
C) arginine and lysine 
D) serine and threonine

Question 10

Which statement is correct about the β-α-β motif?

Accepted Answer

A) The 2 β-strands are antiparallel. 
B) The peptide segment connecting the β-strands usually contains no more than 5 amino acids. 
C) The peptide segment connecting the 2 β-strands commonly contains proline. 
D) The crossover connection itself contains an α-helical segment. 
A) The 2 β-strands are antiparallel. 
B) The peptide segment connecting the β-strands usually contains no more than 5 amino acids. 
C) The peptide segment connecting the 2 β-strands commonly contains proline. 
D) The crossover connection itself contains an α-helical segment.

Question 11

What type of structure does an amino acid sequence have?

Accepted Answer

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

Question 12

Which of the following is/are capable of forming hydrogen bonds with the amino acid side chains located on the surface of a protein?

Accepted Answer

A) the water solvent 
B) the protein interior 
C) distant surface amino acid side chains 
D) interior amino acid side chains 
A) the water solvent 
B) the protein interior 
C) distant surface amino acid side chains 
D) interior amino acid side chains

Question 13

Which molecule is an example of an antiparallel α-helix protein?

Accepted Answer

A) pyruvate kinase 
B) flavodoxin 
C) hemoglobin 
D) papain 
A) pyruvate kinase 
B) flavodoxin 
C) hemoglobin 
D) papain

Question 14

Which of the following is NOT a characteristic of collagen?

Accepted Answer

A) Tropocollagen is the basic structural unit. 
B) Both intermolecular and intramolecular crosslinks help to stabilize the collagen fibrils. 
C) Modification of prolines occurs prior to collagen synthesis. 
D) Inextensible fibrous proteins are components of connective tissues. 
A) Tropocollagen is the basic structural unit. 
B) Both intermolecular and intramolecular crosslinks help to stabilize the collagen fibrils. 
C) Modification of prolines occurs prior to collagen synthesis. 
D) Inextensible fibrous proteins are components of connective tissues.

Question 15

If the following section of a polypeptide is folded into an a-helix,to which amino acid is the carbonyl group of alanine hydrogen bonded?
Ala-Ser-Val-Asp-Glu-Leu-Gly

Accepted Answer

A) aspartic acid 
B) glutamic acid 
C) leucine 
D) valine 
A) aspartic acid 
B) glutamic acid 
C) leucine 
D) valine

Question 16

How are the hydrophobic residues typically arranged in antiparallel β-sheets?

Accepted Answer

A) on both sides of the sheet 
B) in the plane of the sheet 
C) on one side of the sheet 
D) unevenly distributed on either side of the sheet 
A) on both sides of the sheet 
B) in the plane of the sheet 
C) on one side of the sheet 
D) unevenly distributed on either side of the sheet

Question 17

Which of these proteins help other proteins to fold?

Accepted Answer

A) immunoglobulins 
B) phospholipases 
C) synthetases 
D) molecular chaperones 
A) immunoglobulins 
B) phospholipases 
C) synthetases 
D) molecular chaperones

Question 18

Which of the following does NOT determine secondary and higher orders of structure?

Accepted Answer

A) hydrophobic interactions 
B) hydrogen bonds 
C) van der Waals forces 
D) peptide bonds 
A) hydrophobic interactions 
B) hydrogen bonds 
C) van der Waals forces 
D) peptide bonds

Question 19

Which amino acid residue participates in stabilizing the staggered triple helix along its centre?

Accepted Answer

A) Glu 
B) Lys 
C) Pro 
D) Gly 
A) Glu 
B) Lys 
C) Pro 
D) Gly

Question 20

What type of polypeptide chains produces long fibres or large sheets in fibrous proteins?

Accepted Answer

A) those with an abundance of aromatic amino acids 
B) those with an abundance of hydrophilic amino acids 
C) those organized approximately parallel along a single axis 
D) those with amino acids arranged in a repeating (-a-b-c-d-)n sequence 
A) those with an abundance of aromatic amino acids 
B) those with an abundance of hydrophilic amino acids 
C) those organized approximately parallel along a single axis 
D) those with amino acids arranged in a repeating (-a-b-c-d-)n sequence

Exam 6: Proteins: Secondary, tertiary, and Quaternary Structure

Which component is involved with hydrogen bonding of the carbonyl oxygen in a b-turn of peptide chain?

Which combination of atoms forms the resonance structure within the "amide plane"?

Which of the following is a feature of antiparallel b-sheets?

Which characteristic of a peptide contains all the information necessary for folding the peptide chain into its "native" structure?

Which of the following is NOT a class of globular proteins according to type and arrangement of secondary structure?

What is the "Greek key" topology composed of?

Silk fibres consist of fibroin proteins that are comprised of which alternating amino acid residues?

Which statement is NOT correct regarding the tertiary structure of the enzyme triose phosphate isomerase?

Which 2 amino acids act as helix breakers due to their unique structure,which fixes the value of the Cα-N-C bond angle?

Which statement is correct about the β-α-β motif?

What type of structure does an amino acid sequence have?

Which of the following is/are capable of forming hydrogen bonds with the amino acid side chains located on the surface of a protein?

Which molecule is an example of an antiparallel α-helix protein?

Which of the following is NOT a characteristic of collagen?

If the following section of a polypeptide is folded into an a-helix,to which amino acid is the carbonyl group of alanine hydrogen bonded? Ala-Ser-Val-Asp-Glu-Leu-Gly

How are the hydrophobic residues typically arranged in antiparallel β-sheets?

Which of these proteins help other proteins to fold?

Which of the following does NOT determine secondary and higher orders of structure?

Which amino acid residue participates in stabilizing the staggered triple helix along its centre?

What type of polypeptide chains produces long fibres or large sheets in fibrous proteins?

The Facts of Life: Chemistry Is the Logic of Biological Phenomena

Water: the Medium of Life

Thermodynamics of Biological Systems

Amino Acids

Proteins: Their Primary Structure and Biological Functions

Carbohydrates and the Glycoconjugates of Cell Surfaces

Lipids

Lipid Biosynthesis

Membranes and Membrane Transport

The Reception and Transmission of Extracellular Information

Enzymes Kinetics and Specificity

Mechanisms of Enzyme Action

Enzyme Regulation

Molecular Motors

Nutrition and the Organization of Metabolism

Glycolysis

The Tricarboxylic Acid Cycle

Electron Transport and Oxidative Phosphorylation

Photosynthesis

Gluconeogenesis, glycogen Metabolism, and the Pentose Phosphate Pathway

Fatty Acid Catabolism

Nitrogen Acquisition and Amino Acid Metabolism

Nucleotides and Nucleic Acids

Structure of Nucleic Acids

Synthesis and Degradation of Nucleotides

Recombinant Dna: Cloning and Creation of Chimeric Genes

DNA Metabolism: Replication, recombination, and Repair

Transcription and the Regulation of Gene Expression

Protein Synthesis

Post-Transcriptional Regulation of Gene Expression

Completing the Protein Life Cycle: Folding, processing, and Degradation

Metabolic Integration and Organ Specialization

Filters

Which 2 amino acids act as helix breakers due to their unique structure,which fixes the value of the C_α-N-C bond angle?