CHEMISTRY FINAL EXAM III
Which of the following is not an amino acid typically found in human proteins? a. asparagine b. ornithine c. isoleucine d. proline
b.
known for their role as catalysts (enzymes)
catalytic proteins
What is the area of an enzyme where catalysis of a substrate occurs called? a. substrate area b. active area c. substrate site d. active site
d.
bind to small biomolecules, transport them to other locations in the body, and release them as needed
transport proteins
Refer to figure 42: Which structure below does not have at least one chiral center? a. b. c. d.
a.
protein molecules with elongated shape, serve as coatings for organisms or structural material
fibrous proteins
A single amino substitution can give rise to a malfunctioning protein. a. True b. False
a.
An ____ is a glycoprotein produced by an organism in response to an invasion of a foreign substance known as a _____. a. antibody; antigen b. antigen; immunoglobulin c. antigen; antibody d. antibody; immunoglobulin
a.
At its isoelectric pH, glycine will have a. both of its ionizable functional groups dissociated b. neither of its ionizable functional groups dissociated c. only its carboxyl group dissociated d. only its amino group dissociated
a.
In general, the amino acids which occur in human proteins a. are of the L-form b. are of the D-form c. are a 50-50 mix of the L-and D-form d. do not have L- and D- forms
a.
Refer to figure 45: a. nonpolar b. polar neutral c. polar acidic d. polar basic e. uncommon
a.
Refer to figure 47: Name the sequence of amino acids. a. Leu-Ser-Met b. Lys-Tyr-Cys c. Met-Ser-Leu d. Ala-Thr-Met
a.
The amino and carboxyl groups of amino acids are bonded to which carbon? a. both are bonded to the theta-carbon b. both are bonded to the beta-carbon c. the amino is bonded to the theta-carbon and the carboxyl is bonded to the beta-carbon d. the amino is bonded to the beta-carbon, and the carboxyl is bonded to the theta-carbon
a.
The pKa values of the alpha carboxyl (-COOH) groups of common amino acids are around a. 2 b. 5 c. 7 d. 9
a.
The side chain groups of amino acids are bonded to which carbon? a. the theta-carbon b. the beta-carbon c. the carbonyl carbon d. different amino acids have their side chains attached to different carbons
a.
What function does the substrate perform in an enzyme-catalyzed reaction? a. it is the substance upon which the enzyme acts b. it is the product of the reaction c. it acts as a cofactor to carry functional groups d. it acts as a coenzyme in the reaction
a.
Which amino acid is classified as polar? a. Lys b. Leu c. Pro d. Gly
a.
Which amino acid takes on a negative charge when the R-group loses a proton? a. glutamic acid b. histidine c. glutamine d. lysine e. serine
a.
Which of the following is true about sickle cell hemoglobin? a. it has a single amino acid substitution b. it causes a disease that is always fatal c. it is found as a monomer instead of a tetramer in red blood cells d. none of the choices
a.
Which of the following statements is true about an enzyme's absolute specificity? a. enzyme will catalyze a particular reaction for only one substrate b. enzyme will catalyze the same reaction for several substrates c. enzyme can distinguish between stereoisomers of one substrate d. enzyme recognizes the same type of linkage in different substrates
a.
Chiral objects a. are cyclic compounds b. are not superimposable on their mirror images c. never occur in nature d. do not form crystals
b.
Hydrogen bonds are MOST important in this type of structure in proteins: a. primary structure b. secondary structure c. tertiary structure d. quaternary structure e. all of these
b.
If an enzyme has an optimum pH of 7.0, what effect would decreasing the pH to 5.5 have on the rate of a reaction catalyzed by the enzyme? a. increasing the reaction rate b. decreasing the reaction rate c. no effect on reaction rate d. impossible to tell
b.
Refer to figure 46: Refer to Exhibit A. Which one has the R-group with the highest pKa? a. alanine b. arginine c. histidine d. cysteine e. aspartic acid
b.
Refer to this peptide: Cys-Ala-Gly-Arg-Gln-Met The amino terminal amino acid is: a. Arg b. Cys c. Gln d. Met e. none of these
b.
The information needed for the structure of a protein is contained in a. amino acid composition b. primary structure c. secondary structure d. tertiary structure
b.
The order in which amino acids are linked in peptides is given a. from the C-terminal to the N-terminal end b. from the N-terminal to the C-terminal end c. in alphabetical order d. in order of increasing molecular weights of the amino acid residues
b.
The pKa values of the amino (-NH2) groups of common amino acids a. occur at very low pH values b. occur in range from pH 9 to pH 11 c. all occur at pH 7 d. all occur above pH 13
b.
What are enzymes? a. cofactors that carry functional groups during biological synthesis b. specialized catalysts of biochemical reactions c. structural components of cell membranes d. both (a) and (b)
b.
What is the charge on the tetrapeptide Lys-Lys-Ser-Glu at pH 7? a. 0 b. +1 c. +2 d. -1
b.
What is the predominant form of the amino acid abbreviated Val at pH 7? a. positive b. neutral c. negative
b.
Which amino acid has a basic R group? a. glutamic acid b. lysine c. isoleucine d. serine e. tyrosine
b.
Which amino acid has the three-letter symbol Asn? a. aspartic acid b. asparagine c. alanine d. arginine
b.
Which amino acid takes on a positive charge when the R-group gains a proton? a. glutamic acid b. histidine c. glutamine d. tyrosine e. glycine
b.
Which amino acids contain sulfur? a. cysteine and lysine b. cysteine and methionine c. arginine and methionine d. cysteine and isoleucine
b.
Which of the following amino acids has a side chain that can make hydrogen bonds to other molecules? a. Leu b. Ser c. Ala d. Gly
b.
Which of the following is NOT a correct combination of an amino acid, its three-letter designation? a. Lysine, Lys b. Glycine, Gln c. Histidine, His d. Tryptophan, Trp e. Arginine, Arg
b.
Which of the following is the most common function for fibrous proteins? a. enzymes b. structural roles c. carrier molecules d. enzymes and carrier molecules e. all of these
b.
Disulfide bonds in proteins occur between the side chains of which of the following amino acid residues? a. glutamine b. lysine c. cysteine d. methionine
c.
Given the R-groups in the peptide, Ala-Gly-Phe-Ser-Val, it would likely be: a. very water soluble b. somewhat water soluble c. not very water soluble d. you cannot tell from the sequence
c.
Refer to figure 43: What is the type of interaction pictured here? a. hydrophobic interaction b. hydrogen bond c. salt bridge d. dipole-dipole interaction
c.
Refer to figure 44: What do the structures of amino acids have in common? a. b. c. d. e. nothing
c.
What is the predominant form of the amino acid abbreviated Glu at pH 7? a. positive b. neutral c. negative
c.
Which of the following amino acids is unlikely to be found in an theta-helix? a. phenylalanine b. tryptophan c. proline d. lysine
c.
Which of the following as no L or D configuration (i.e. no chiral center)? a. glutamic acid b. proline c. glycine d. all of these have an L or D configuration
c.
Which of the following best describes the structure of collagen? a. it is composed of a single theta-helix b. it is a double helix c. it is a triple helix d. it is composed primarily of beta-sheet
c.
Which of the following best describes what happens to a small peptide when placed in an acid solution and heated? a. the small peptide combines to form a long-chain protein b. the small peptide is resistant to acid and heat c. the small peptide undergoes hydrolysis to produce free amino acids d. the small peptide undergoes hydrolysis to produce free amino acids, which recombine upon cooling to form a different peptide
c.
necessary for all forms of movement
contractile proteins
Which groups of a pair of amino acids must react to form a peptide bond? a. the two carboxyls b. the two aminos c. the two R-groups d. the carboxyl of one and the amino of the other
d,
Hydrogen bonds a. are weak and unstable b. are not involved in protein structure c. do not involve hydrogen d. hold together a theta-helices and Beta-sheets in proteins e. are much stronger than covalent bonds
d.
Refer to this peptide: Cys-Ala-Gly-Arg-Gln-Met The carboxyl terminal end is: a. Arg b. Cys c. Gln d. Met e. none of these
d.
The peptide bond a. is planar b. can be written as a resonance hybrid c. is the basis of protein structure d. all of the above
d.
What is the consequence of protein denaturation? a. partial or complete loss of a protein's three-dimensional structure b. loss of biochemical activity of the protein c. disruption of the secondary, tertiary, and quaternary structural interactions d. all of the above
d.
What type of attractive interaction, that contributes to the tertiary structure of a protein, would be found buried in a nonaqueous environment within the protein? a. hydrogen bonds b. salt bridges c. hydrophilic interactions d. hydrophobic interactions
d.
When a charged carboxylate side-chain of one amino acid in a protein is in close proximity to a charged amino group of another amino acid at (pH=7), we call the resulting interaction a(n) a. dipole-dipole bond b. hydrophobic interaction c. hydrogen bond d. salt bridge
d.
Which amino acid contains a phenol-like ring structure? a. glutamic acid b. histidine c. isoleucine d. tyrosine
d.
Which amino acid has a polar, non-ionic R-group (neutral) a. glutamic acid b. histidine c. isoleucine d. serine e. lysine
d.
Which amino acid has the 3-letter symbol Glu? a. glycine b. glutamine c. glucose d. glutamic acid
d.
Which group consists only of amino acids with carboxylate side chains? a. glutamate and cysteine b. aspartate and glycine c. glutamate and lysine d. aspartate and glutamate
d.
Which of the following can result in protein denaturation? a. heat b. extremes of pH c. detergents d. all of the above
d.
Which of the following is true about oxytocin? a. it is a peptide hormone b. during pregnancy the number of receptors for oxytocin increases c. it is involved in stimulating the flow of milk during nursing d. all of the choices
d.
central to functioning of the body's immune system
defense proteins
Which of the following correctly describes peptide bonds? a. they are special type of amide bond b. they are a very stable bonds c. they are formed when water is split out from an amino group and a carboxylic acid d. they are a bond which displays resonance e. all of these
e.
Which of the following diseases is based on abnormal protein folding, aggregation, or processing? a. Alzheimers disease b. Prion (Mad Cow) diseases c. Parkinson's disease d. Frontotemporal dementia e. all of the choices
e.
protein molecules with peptide chains folded into spherical or globular shapes, water soluble substances, (hydrophobic amino acid residues are in the protein core)
globular proteins
contain carbohydrates or carbohydrate derivatives in addition to amino acids
glycoproteins
produced as a protective response to the invasion of microorganisms or foreign molecules. Serve as antibodies to combat invasion of the body by antigens
immunoglobulins
conjugated proteins that contain lipids and amino acids. Help suspend lipids and transport them through the bloodstream
lipoproteins
proteins associated with cell membranes, insoluble in water, hydrophobic amino acid residues are on the surface
membrane proteins
transmit signals to coordinate biochemical processes between different cells, tissues, and organs
messenger proteins
partial or complete disorganization of a protein's characteristic three-dimensional shape
protein denaturation
found embedded in the exterior surface of cell membranes
regulatory proteins
confer stiffness and rigidity
structural proteins
