Chem Chapter 17, 18, 19 Flashcards
All of the statements concerning citric acid are true except
-it is produced only by plants.
-its salts are used in many consumer products.
-it is very soluble in water.
-it is a weak acid.
-it contains three carboxylic acid groups.
-it is produced only by plants.
What two compounds should be used to make N-methylbutanamide?
-methyl amine and 1-butanol
-ammonia and butanoic acid
-ammonia and 1-butanol
-ammonia and methylbutanoate
-methyl amine and butanoic acid
-methyl amine and butanoic acid
What is the IUPAC name of the molecule shown?
-γ-amino-α-hydroxybutyric acid
-α-amino-γ-hydroxybutyric acid
-4-amino-2-hydroxybutanoic acid
-1-amino-3-hydroxybutanoic acid
-none of these
4-amino-2-hydroxybutanoic acid
What is the IUPAC name of the compound shown?
4-butanoic acid
1-butenoic acid
3-butenoic acid
1-butanoic acid
none of the above
3-butenoic acid
Which molecule is oxalic acid?
Which of the following has the highest boiling point?
ethyl alcohol, CH3CH2OH
formaldehyde, HCHO
acetic acid, CH3COOH
dimethyl ketone, CH3COCH3
ethane, CH3CH3
acetic acid, CH3COOH
Which of the following might be obtained as one of the products in this reaction?
Which of the following conditions would favor the carboxylate ion form of a carboxylic acid?
high pH
low pH
both A and B
neither A nor B
high pH
Which is the correct structure for N,N-diethyl benzamide?
Which of the following acids is the weakest?
carbonic acid, pKa1 = 6.35
formic acid, pKa = 3.74
hexanoic acid, pKa = 4.89
oxalic acid, pKa1 = 1.27
acetic acid, pKa = 4.74
carbonic acid, pKa1 = 6.35
What is the IUPAC name for the following compound?
diethyl benzamide
diethyl phenyl amine
ethyl phenyl amine
N,2-diethyl benzamide
N,N-diethyl benzamide
N,2-diethyl benzamide
Which of the following is(are) neither an acid or a base?
amines
carboxylic acids
esters
amides
both C and D
both C and D
What is the common name of the molecule shown?
α-amino-γ-hydroxybutyric acid
1-amino-3-hydroxybutanoic acid
γ-amino-α-hydroxybutyric acid
4-amino-2-hydroxybutanoic acid
none of these
γ-amino-α-hydroxybutyric acid
Which molecule is an ester?
Which equation correctly represents the dissociation of a carboxylic acid in water?
What is the IUPAC name of the compound shown?
N-methyl butanamide
2-methyl butanamide
3-methyl butanamide
N-methyl propanamide
2-methyl propanamide
3-methyl butanamide
What is the correct structure for the compound isopropylbenzoate?
Which carboxylic acid is used to prepare the ester shown?
When an amide is hydrolyzed under basic conditions, the products are an
-amine and a carboxylic acid.
-ammonium ion and a carboxylic acid.
-amine and a carboxylate ion.
-ammonium ion and a carboxylate ion.
-There is no reaction.
-amine and a carboxylate ion.
When an alcohol reacts with phosphoric acid, the product is referred to as a
phosphate salt.
phosphate anion.
pyrophosphate.
phosphate ester.
none of the above
phosphate ester.
When a protein is ________, its primary structure is destroyed, thus destroying the other aspects of its structure.
esterified
denatured
polymerized
hydrolyzed
ionized
hydrolyzed
Polar R groups, along with acidic and basic R groups, are said to be ________ because they are attracted to water molecules.
hydrophobic
hydrophilic
ionized
unreactive
none of these
hydrophilic
Which type of interaction is not directly involved in maintaining tertiary structure?
hydrophobic interactions
peptide bonds
salt bridges
disulfide bridges
hydrogen bonding
peptide bonds
Which of the following processes involve protein denaturation?
whipping cream
permanent waving of hair
cooking egg whites
More than one response is correct.
More than one response is correct.
An amino acid will have the form shown at
-a pH of 7.0.
-a pH greater than its isoelectric point.
-a pH less than its isoelectric point.
-its isoelectric point.
-any pH other than 7.0.
-a pH less than its isoelectric point.
Which of these amino acids has a thiol group as part of its side chain?
cysteine
methionine
threonine
tyrosine
histidine
cysteine
The protein configuration that is primarily determined from interactions between R groups is the
primary structure.
secondary structure.
tertiary structure.
quaternary structure.
none of the above
tertiary structure.
The amino acid sequence of a protein is known as its
primary structure.
secondary structure.
tertiary structure.
quaternary structure.
none of the above
primary structure.
The type of bond that is most important in maintaining secondary structure of a protein is
hydrogen bonding within the backbone.
hydrophobic interactions.
disulfide bridges.
hydrogen bonding between R groups.
salt bridges.
hydrogen bonding within the backbone.
When a protein is ________, its primary structure is maintained, but other aspects of its structure are disrupted.
esterified
hydrolyzed
ionized
polymerized
denatured
denatured
Which amino acid is classified as basic?
glutamic acid
lysine
threonine
valine
phenylalanine
lysine
Which of the following amino acids contains an alcohol group?
Asp
Cys
Phe
Val
Thr
Thr
Amino acids used in proteins generally are
d-amino acids.
l-amino acids.
α-amino acids.
All are correct.
None are correct.
l-amino acids.
All of the following are globular proteins except
albumin.
hemoglobin.
myosin.
ribonuclease.
immunoglobulin.
myosin.
An amino acid whose R group is predominantly hydrocarbon would be classified as
isoelectric.
basic.
polar.
non-polar.
acidic.
non-polar.
Which of the following is the structure for the amino acid with the abbreviation of Phe?
Myoglobin is a protein that contains oxygen in the muscle. What class of protein does it belong to?
structural protein
protective protein
enzyme
transport protein
storage protein
storage protein
The pH at which the positive and negative charges of an amino acid balance each other is called the
isobaric point.
isoelectric point.
isotonic point.
isomer point.
isobestic point.
isoelectric point.
The quaternary structure of hemoglobin contains
six subunits.
four subunits.
two subunits.
eight subunits.
four subunits
All of the following are non-covalent interactions important in maintaining the secondary, tertiary, and quaternary aspects of amino acids except
-sulfur-sulfur bonds.
-hydrophobic interactions between R groups.
-salt bridges between R groups.
-hydrogen bonding between R groups.
-hydrogen bonding along the backbone.
-sulfur-sulfur bonds.
Insulin is an example of a(an)
storage protein.
hormone.
transport protein.
structural protein.
enzyme.
hormone
Detergents would most likely disrupt what type of stabilizing interaction?
hydrophobic interactions
hydrogen bonds
salt bridges
hydrophilic interactions
disulfide bonds
hydrophobic interactions
What type of forces are responsible for maintaining the quaternary structure of a protein?
ionic bonds
hydrophobic interactions
hydrogen bonds
dipole-dipole
all of these
all of these
All of the following are examples of fibrous proteins except
fingernails.
wool.
skin.
bones.
insulin.
insulin
The difference between normal and sickle cell hemoglobin is in which structure?
primary
secondary
tertiary
quaternary
primary
In the tetrapeptide Ala-Cys-Val-Leu, the C-terminal amino acid is
Cys.
Leu.
Ala.
Val.
none of the above
Leu
In the tetrapeptide Ala-Cys-Val-Leu, the N-terminal amino acid is
Cys.
Val.
Ala.
Leu.
none of the above
Ala
Which amino acid is a secondary amine with its nitrogen and the alpha-carbon joined as part of a ring structure?
proline
histidine
lysine
arginine
glycine
proline
Which pair of amino acids can have hydrophobic interactions?
arginine and glutamic acid
aspartic acid and lysine
leucine and alanine
glutamic acid and serine
glycine and asparagine
leucine and alanine
The pKa of glutamic acid’s side chain is 4.3. What is the charge of glutamic acid at a pH of 8?
+2
+1
0
-1
-2
-1
Which of the following is the typical shape of a plot showing the rate of an enzyme-catalyzed reaction as a function of the enzyme concentration with excess substrate?
Enzymes have an optimum temperature for their catalytic activity. This is best explained by the balance between the ________ number of collisions and the ________ rate of denaturation of the enzyme as temperatures increase.
increased; increased
decreased; decreased
decreased; increased
increased; decreased
none of the above
increased; increased
Which of these factors explain how an enzyme works?
-The closeness of the reactants to each other in the active site.
-The orientation of the reactants.
-The weakening of bond energies in the reactants.
-all of the above
-none of the above
-all of the above
Each of the following phrases correctly describes enzymes except
act as catalysts.
behave as substrates.
have a globular shape.
contain an active site.
dissolve in water.
behave as substrates.
Which term identifies the relatively small portion of the enzyme that is directly involved in the biochemical reaction being catalyzed?
substrate
active site
C-terminal
precursor
N-terminal
active site
Which aspect of enzyme structure is related to our dietary need for trace minerals?
turnover number
cofactor
active site
chirality
none of these
cofactor
The name of an enzyme can often be recognized by the ending
-ate.
-ose.
-ase.
-ic acid.
-ene.
ase
The enzyme alcohol dehydrogenase catalyzes the
oxidation of alcohols.
hydrolysis of esters.
oxidation of carbonyls.
removal of water.
reduction of alcohols.
oxidation of alcohols.
The following reaction would most likely be catalyzed by an enzyme of which class?
sucrose + H2O → glucose + fructose
transferase
oxidoreductase
isomerase
synthetase or ligase
hydrolase
hydrolase
A synthetase can be classified as a(an) ________ because its function is joining two molecules together.
ligase
isomerase
oxidoreductase
transferase
hydrolase
ligase
Another term for substances that bind irreversibly with the active site of an enzyme is
coenzymes.
activators.
hormones.
poisons.
zymogens.
poisons.
An enzyme functions best at its optimal temperature. What would possibly happen if the temperature is increased greatly?
-The enzyme would become denatured.
-The reaction rate would increase.
-There would be no effect on the enzyme’s activity.
-The reaction would slow down.
-The enzyme would become denatured.
A model that explains how the substrate fits exactly into the active site of an enzyme is called
an induced-fit.
a lock-and-key.
a coenzyme.
substrate specific.
an active site.
a lock-and-key.
The mechanism of enzyme control that is similar to noncompetitive inhibition because both involve interactions with the enzyme at locations other than the active site is
genetic control.
allosteric interaction.
zymogen production.
zymogen activation.
feedback inhibition.
allosteric interaction.
When a metal ion such as Pb(II) interferes with the functioning of an enzyme, the most probable mechanism is
irreversible inhibition.
reversible competitive inhibition.
genetic control.
feedback control.
reversible noncompetitive inhibition.
irreversible inhibition.
Which factor is not important in explaining how enzymes work?
-The bonds in substrates are subjected to strains which weaken them.
-Two different substrate molecules are brought into close contact.
-Substrates are brought into solution more easily.
-Substrates are forced into the correct orientation for interaction.
-Substrates are placed near acidic or basic sites.
-Substrates are brought into solution more easily.
A multi-step biochemical process in which the rate of an early step is affected by the concentration of products of a later step is said to be subject to
hydrolysis.
pH control.
decomposition.
feedback control.
all of the above
feedback control.
Which mechanism of enzyme control determines the amount of enzyme available?
allosteric control
competitive inhibition
covalent modification
genetic control
zymogen production
genetic control
Antioxidants contribute to good health by reacting with
free radicals.
vitamins.
hormones.
coenzymes.
hydrogen ions.
free radicals.
All of the following statements concerning vitamins are true except
-vitamin C and the B vitamins are water-soluble.
-fat-soluble vitamins have a high proportion of polar carbonyl and hydroxyl groups.
-it is possible to overdose on fat-soluble vitamins because they accumulate in fatty tissues.
-it is difficult to overdose on water-soluble vitamins because excess amounts can be excreted in the urine.
-vitamins A, D, E, and K are fat-soluble.
-fat-soluble vitamins have a high proportion of polar carbonyl and hydroxyl groups.
A form of inhibition that occurs by covalent modification is the
-dephosphorylation of an active site by hydrolysis.
-transfer of a phosphate group to ADP.
-phosphorylation of an active site by ATP.
-all of these
-phosphorylation of an active site by ATP.
Activation of zymogens involves the chemical process of
complete hydrolysis.
denaturation.
covalent modification.
oxidation-reduction.
hydrogen bonding.
covalent modification.
Enzymes that are affected by the binding of an activator are called
induced enzymes.
proenzymes.
allosteric enzymes.
zymogens.
allosteric enzymes.
When a molecule other than the correct substrate interacts with some part of an enzyme to alter the shape of the active site, the process is called
competitive inhibition.
noncompetitive inhibition.
irreversible inhibition.
activation.
covalent modification.
noncompetitive inhibition.
When substrate molecules occupy all of the active sites in the enzyme available for a particular reaction, the enzyme is said to be
activated.
hydrolyzed.
saturated.
denatured.
inhibited.
saturated
