Question 1

Between which of these amino acid pairs might a hydrophobic interaction occur?

Accepted Answer

A) Ser/Ile 
B) Val/Leu 
C) Tyr/Cys 
D) His/Val 
A) Ser/Ile 
B) Val/Leu 
C) Tyr/Cys 
D) His/Val

Question 2

Which structure consists mainly of polar and charged residues on its outward face and mostly non-polar,hydrophobic residues on its inner face?

Accepted Answer

A) β-sheet 
B) triple helix 
C) β-turn 
D) amphiphilic helix 
A) β-sheet 
B) triple helix 
C) β-turn 
D) amphiphilic helix

Question 3

Which amino acid residue is most likely to be found in a beta turn?

Accepted Answer

A) glycine 
B) alanine 
C) valine 
D) leucine 
A) glycine 
B) alanine 
C) valine 
D) leucine

Question 4

Which of these molecules is an example of a disulfide-rich protein?

Accepted Answer

A) insulin 
B) glyceraldehyde-3-phosphate dehydrogenase 
C) hemoglobin 
D) triose phosphate isomerase 
A) insulin 
B) glyceraldehyde-3-phosphate dehydrogenase 
C) hemoglobin 
D) triose phosphate isomerase

Question 5

How many residues further up the a-helical chain is each peptide carbonyl group hydrogen bonded to the peptide N-H group?

Accepted Answer

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

Question 6

Between which of the following amino acid pairs might an electrostatic interaction occur within a protein at typical physiological pH?

Accepted Answer

A) Ser/Asn 
B) Asp/Glu 
C) Arg/Cys 
D) Lys/Asp 
A) Ser/Asn 
B) Asp/Glu 
C) Arg/Cys 
D) Lys/Asp

Question 7

Polylysine is a random coil when the pH is less than 11,while it forms an a-helix if the pH is raised to greater than 12.What happens at pH 12 to account for this?

Accepted Answer

A) The lysine residues are negatively charged,which electrostatically stabilizes the helix. 
B) The positive charges on the lysine residues stabilize the a-helix. 
C) The lysine residues are neutral,which eliminates electrostatic repulsion between the R groups. 
D) The high concentration of OH⁻ ions in solution reduces the electrostatic repulsion between the R groups. 
A) The lysine residues are negatively charged,which electrostatically stabilizes the helix. 
B) The positive charges on the lysine residues stabilize the a-helix. 
C) The lysine residues are neutral,which eliminates electrostatic repulsion between the R groups. 
D) The high concentration of OH⁻ ions in solution reduces the electrostatic repulsion between the R groups.

Question 8

Which amino acid commonly comprises flexible,disordered segments of proteins?

Accepted Answer

A) Leu 
B) Lys 
C) Ser 
D) Asp 
A) Leu 
B) Lys 
C) Ser 
D) Asp

Question 9

Which of the following structures form between 2 normal β-structure hydrogen bonds and are comprised of 2 residues on 1 strand and 1 residue on the opposite strand?

Accepted Answer

A) β-barrels 
B) parallel β-sheets 
C) β-turns 
D) β-bulges 
A) β-barrels 
B) parallel β-sheets 
C) β-turns 
D) β-bulges

Question 10

Which non-covalent interaction between tightly packed amino acid side chains in the interior of the protein is a major contributor to protein structure?

Accepted Answer

A) hydrogen bonding 
B) electrostatic interactions 
C) covalent ester bonding 
D) van der Waals interactions 
A) hydrogen bonding 
B) electrostatic interactions 
C) covalent ester bonding 
D) van der Waals interactions

Question 11

When the peptide (AEFFLAMEP)forms an a-helix,which amino acid residue would be closest to being in the same position on the same face of the helix as is the initial alanine residue?

Accepted Answer

A) F(3) 
B) A(6) 
C) E(8) 
D) P(9) 
A) F(3) 
B) A(6) 
C) E(8) 
D) P(9)

Question 12

What defines tertiary structure?

Accepted Answer

A) the sequence of amino acids 
B) the folding of a single polypeptide chain in 3-dimensional space 
C) hydrogen-bonding interactions between adjacent amino acid residues into helical or pleated segments 
D) the way in which separate,folded,monomeric,protein subunits associate to form oligomeric proteins 
A) the sequence of amino acids 
B) the folding of a single polypeptide chain in 3-dimensional space 
C) hydrogen-bonding interactions between adjacent amino acid residues into helical or pleated segments 
D) the way in which separate,folded,monomeric,protein subunits associate to form oligomeric proteins

Question 13

Which characteristic is NOT a structural and functional advantage to quaternary structure?

Accepted Answer

A) cooperativity 
B) instability 
C) bringing catalytic sites together 
D) genetic economy and efficiency 
A) cooperativity 
B) instability 
C) bringing catalytic sites together 
D) genetic economy and efficiency

Question 14

Which of the following in NOT a characteristic of triose phosphate isomerase's tertiary structure?

Accepted Answer

A) Its a-helices are in the interior core of the molecular structure. 
B) It contains a b-barrel in the centre of its structure. 
C) It is composed entirely of alternating a-helices and b-strands. 
D) Hydrophobic residues are buried between concentric layers. 
A) Its a-helices are in the interior core of the molecular structure. 
B) It contains a b-barrel in the centre of its structure. 
C) It is composed entirely of alternating a-helices and b-strands. 
D) Hydrophobic residues are buried between concentric layers.

Question 15

What can be deduced from a Ramachandran plot?

Accepted Answer

A) the amino acid residues that have the greatest degree of rotational freedom 
B) the sterically allowed rotational angles between R groups and a-carbons in a peptide 
C) the sterically allowed rotational angles between Cα and the amide nitrogen (Cα-N),as well as between Cα and the amide carbonyl carbon (Cα-CO) 
D) the sterically allowed rotational angles about the amide nitrogen (NH)and CO 
A) the amino acid residues that have the greatest degree of rotational freedom 
B) the sterically allowed rotational angles between R groups and a-carbons in a peptide 
C) the sterically allowed rotational angles between Cα and the amide nitrogen (Cα-N),as well as between Cα and the amide carbonyl carbon (Cα-CO) 
D) the sterically allowed rotational angles about the amide nitrogen (NH)and CO

Question 16

Rotation is allowed about which bond within a polypeptide chain?

Accepted Answer

A) the α-carbon and carbonyl carbon 
B) the β-carbon and carbonyl carbon 
C) the carbonyl carbon and the nitrogen of the peptide bond 
D) the α-carbon and nitrogen of the peptide bond 
A) the α-carbon and carbonyl carbon 
B) the β-carbon and carbonyl carbon 
C) the carbonyl carbon and the nitrogen of the peptide bond 
D) the α-carbon and nitrogen of the peptide bond

Question 17

What type of amino acids can be found on the surface of a protein?

Accepted Answer

A) only polar 
B) only non-polar 
C) mostly non-polar 
D) both polar and non-polar 
A) only polar 
B) only non-polar 
C) mostly non-polar 
D) both polar and non-polar

Question 18

What type of amino acid residue fills the space between the helices in hemoglobin most efficiently and tightly?

Accepted Answer

A) hydrophobic 
B) polar 
C) acidic 
D) basic 
A) hydrophobic 
B) polar 
C) acidic 
D) basic

Question 19

Which structure accommodates the unique composition of collagen?

Accepted Answer

A) β-pleated sheet 
B) triple helix 
C) helix-turn-helix motif 
D) coiled coil 
A) β-pleated sheet 
B) triple helix 
C) helix-turn-helix motif 
D) coiled coil

Question 20

Which of the following does NOT occur during the folding of globular proteins into a proper structure?

Accepted Answer

A) "molten globule" formation of assembled domains 
B) formation of domains through cooperative aggregation of folding nuclei 
C) adjustment in the confirmation of domains 
D) rapid and reversible formation of local secondary structure 
A) "molten globule" formation of assembled domains 
B) formation of domains through cooperative aggregation of folding nuclei 
C) adjustment in the confirmation of domains 
D) rapid and reversible formation of local secondary structure

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

Between which of these amino acid pairs might a hydrophobic interaction occur?

Which structure consists mainly of polar and charged residues on its outward face and mostly non-polar,hydrophobic residues on its inner face?

Which amino acid residue is most likely to be found in a beta turn?

Which of these molecules is an example of a disulfide-rich protein?

How many residues further up the a-helical chain is each peptide carbonyl group hydrogen bonded to the peptide N-H group?

Between which of the following amino acid pairs might an electrostatic interaction occur within a protein at typical physiological pH?

Polylysine is a random coil when the pH is less than 11,while it forms an a-helix if the pH is raised to greater than 12.What happens at pH 12 to account for this?

Which amino acid commonly comprises flexible,disordered segments of proteins?

Which of the following structures form between 2 normal β-structure hydrogen bonds and are comprised of 2 residues on 1 strand and 1 residue on the opposite strand?

Which non-covalent interaction between tightly packed amino acid side chains in the interior of the protein is a major contributor to protein structure?

When the peptide (AEFFLAMEP)forms an a-helix,which amino acid residue would be closest to being in the same position on the same face of the helix as is the initial alanine residue?

What defines tertiary structure?

Which characteristic is NOT a structural and functional advantage to quaternary structure?

Which of the following in NOT a characteristic of triose phosphate isomerase's tertiary structure?

What can be deduced from a Ramachandran plot?

Rotation is allowed about which bond within a polypeptide chain?

What type of amino acids can be found on the surface of a protein?

What type of amino acid residue fills the space between the helices in hemoglobin most efficiently and tightly?

Which structure accommodates the unique composition of collagen?

Which of the following does NOT occur during the folding of globular proteins into a proper structure?

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

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