Quiz Practice!!

Which of the following are contributing to the spontaneous nature of the protein folding process? a. formation of hydrogen bonds and electrostatic interactions b. loss of translational freedom as portions of the protein interact c. formation of hydrophobic interactions d. none of the above

A and C

Which of the following could contribute to quaternary structure? a.charge-charge interaction between arginine and glutamic acid b.disulfide bond c. hydrogen bond between threonine hydroxyl group and imidazole ring of histidine d. hydrophobic interaction between phenylalanine and tryptophan

A,B,C, and D

Which of the following would contribute to tertiary structure? a. charge-charge interaction between lysine and aspartic acid b. disulfide bond c. hydrogen bond between serine hydroxyl group and amide of glutamine d. hydrophobic interaction between leucine and valine

A,B,C, and D

Identify the amino acid(s) whose side chain can act as both hydrogen bond donors and acceptors, regardless of the pH: a. N b. Q c. S d. T e. K

A,B,C, or D: N, Q, S, or T

Homologous proteins such as hemoglobin from different organisms a.have nearly identical lengths. b. share little sequence homology with other proteins with similar function e.g. myoglobin. c. share a significant degree of sequence similarity. d. perform the same function in different organisms. e. have sequence identity in direct correlation to the relatedness of the species from which they were derived.

A,C,D,E

Which of the following definitions are not properly matched with the respective proteins? a. Amylase: Transport/storage protein B. b. Collagen: Structural protein c. Antibody: Immune system molecule d. Hemoglobin: Transport protein e. Actin: Required for muscle contraction

A: Amylase: Transport/storage protein B.

The tertiary structure of a protein refers to the: a.Interaction of secondary structures to form a compact unit b.Protein elasticity c.Volume of protein d.Three connected residues of a protein e.none of the above

A: Interaction of secondary structures to form a compact unit

Biomolecular Hierarchy: The structural integrity of supramolecular complexes (assemblies) of multiple components are bonded to each other mostly by all of the following forces EXCEPT: a. covalent bonds b. van der Waals forces c. hydrogen bonds d. hydrophobic interactions e. ionic interactions

A: covalent bonds

Alpha helices are stabilized primarily by: a. hydrogen bonds between the main chain peptide bond component atoms. b. electrostatic interactions between R-groups. c. hydrophobic interactions between the alpha-carbons of the main chain. d. hydrogen bonding between the R-groups. e. hydrophobic interactions between R-groups and the solvent water.

A: hydrogen bonds between the main chain peptide bond component atoms

Proinsulin is converted into insulin by: a. proteolytic excision of a specific peptide b. allosteric binding of glucose c. phosphorylation to the active form d. removal of phosphate by converter enzymes

A: proteolytic excision of a specific peptide

Protein degradation is compartmentalized either in macromolecular structures known as: a. proteosomes b. golgi c. endoplasimic reticulum d. mitchondria

A: proteosomes

What are the characteristics of globular proteins? a. Insoluble in water. b. Roughly spherical. c. Folded so that the hydrophobic amino acids are in the interior of the molecule. d. Hydrophobic side chains are exposed to the water.

B and C

Proteins that do NOT perform any obvious chemical transformation, but control the ability of other proteins to carry out their physiological functions are: a. enzymes b. regulatory proteins c. transport proteins d. storage proteins e. structural proteins

B: regulatory proteins

Proteolytic cleavage has been shown to be involved in all of the following processes: a. inactivation of regulatory enzymes b. elimination of the N-terminal Met residue c. activation of zymogens. d. elimination of signal sequences after the protein has reached its proper location e. digestion of dietary proteins

B,C,D, and E

Which of the following contributes to a favorable Gibson free energy state for protein folding? a. conformational entropy b.hydrophobic effect c. charge-charge interactions d. internal hydrogen bonds e. van der Waals interactions

B,C,D,E

Tertiary structure is defined as: a.the sequence of amino acids. b.the folding of a single polypeptide chain in three-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.

B: the folding of a single polypeptide chain in three-dimensional space.

If an aspartic acid residue were present in the interior of a globular protein, it would most likely be: a. deprotonated and thus negatively charged b. tightly associated with the R-group of a lysine residue c. react with a cysteine to form a thioester d. react with a serine to form an ester

B: tight;y associated with the R-group of a lysine residue

The primary driving force for folding is/are? Thus, aggregation is likely to happen if crowding occurs. a. hydrogen bonding b. dehydration c. hydrophobic interaction d. none of the above

C: hydrophobic interaction

Hemoglobin is an example of a(n): a. enzymes b. regulatory proteins c. transport proteins d. storage proteins e. structural proteins

C: transport proteins

A highly conserved protein that is involved in degradation of damaged protein: a. ricin b. met-aminopeptidase c. ubiquitin d. degradase e. peptidyl transferase

C: ubiquitin

In the tertiary structure of a protein, an electrostatic interaction could form between the R-groups of which two amino acids? a. Gln and Lys b. Asp and Thr c. Leu and Asp d. Glu and Arg e. Arg and His

D: Glu and Arg

Which of the following items was one of the crucial elements of the Anfinsen experiment with ribonuclease A? a. hydrophobic interactions were disrupted by the addition of beta-mercaptoethanol b.correct formation of disulfide bonds was achieved even with urea present c. removal of beta-mercaptoethanol resulted in complete denaturation of the protein d.the presence of 8 cysteine residues means that there are 105 different disulfide bond possibilities

D: the presence of 8 cysteine residues means that there are 105 different disulfide bond possibilities

The most common form of post-translational processing is: a. carbohydrate addition b. lipid addition c. phosphorylation d. adding signal sequences e. proteolytic cleavage

E: proteolytic cleavage