Quiz: Basic Principles of Biochemistry
Score for this attempt: 76 out of 80
Submitted Aug 25 at 9:46am
This attempt took 49 minutes.
Question 1
2 / 2 pts
Which elements are found in simple carbohydrates?
carbon, hydrogen, oxygen and nitrogen
carbon, hydrogen, oxygen and sulfur
carbon, hydrogen, oxygen and phosphorous
C !
carbon, hydrogen and oxygen
none of the above
Question 2
2 / 2 pts
Considering the energetics of transferring nonpolar molecules from water to
a nonpolar solvent, the factor TΔS is generally ________, causing ΔG to be
________.
negligible; either positive or negative
positive; positive
negative; positive
negative; negative
C !
positive; negative
Question 3
2 / 2 pts
Hydrogen bonds within liquid water are ________.
attractions between two oxygen atoms
attractions between the protons of the oxygen nuclei
attractions between the H+ and −OH ions of the liquid
ion-induced dipole interactions
C !
dipole-dipole interactions
Question 4
2 / 2 pts
Which of the following explains the interactions that occur between the
atoms of water molecules and the ions that form when sodium chloride
dissolves in water?
C !
hydrogens interact with the chloride ion, oxygens interact with the sodium
ion
oxygens interact with the sodium ion and the chloride ion
hydrogens interact with the sodium ion, oxygens interact with the chloride
ion
hydrogens interact with the sodium ion and the chloride ion
none of the above
Question 5
2 / 2 pts
Hydrogen bonds are approximately ________% of the bond strength of
covalent C-C or C-H bonds.
20
1
C !
5
95
50
Question 6
2 / 2 pts
Which of the following shows the buffer that is found in the blood stream?
H3PO4 ⇌ H2PO42- + H+
C !
H2CO3 ⇌ HCO3- + H+
HPO42- ⇌ PO43- + H+
H2PO4- ⇌ HPO42- + H+
HCO3- ⇌ CO32- + H+
Question 7
2 / 2 pts
Which of the following is true regarding hydrophobic interactions between
nonpolar molecules or groups?
they are the result of strong attractions between nonpolar regions
they are the result of strong repulsion between water and nonpolar regions
C !
they require the presence of surrounding water molecules
they result from the tendency to maximize water's contact with nonpolar
molecules
they depend on strong permanent dipoles in the nonpolar molecules
Question 8
2 / 2 pts
Which of the following explains the attractive forces between hydrophobic
molecules in an aqueous solution?
C !
there is no increase in attractive forces between nonpolar molecules in an
aqueous environment
in an aqueous environment, London dispersion forces between hydrophobic
molecules and water become stronger
since nonpolar molecules do not form hydrogen bonds with hydrogen bonds
with water, they can form hydrogen bonds with other nonpolar molecules
in an aqueous environment, London dispersion forces between hydrophobic
molecules become stronger
none of the above
Question 9
2 / 2 pts
In a water molecule, hydrogens are partially ________; oxygens are partially
________.
negative; negative
negative; positive
C !
positive; negative
positive; positive
none of the above
Question 10
2 / 2 pts
Which of the following is a physical property of water that results from
hydrogen bonding?
a solid state that is less dense than the liquid state
ability to solubilize polar molecules
high boiling point relative to molecular weight
high surface tension
C !
all of the above
Question 11
2 / 2 pts
A gaseous mixture of hydrogen, water, ammonia and methane can produce
which of the biomolecules when exposed to an electrical discharge (such as
lightning)?
carbohydrates
C !
amino acids
lipids
nucleotides
none of the above
Question 12
2 / 2 pts
The similarity of one organism to another (for example a bacteria versus a
human) is most easily done by comparing which biopolymer?
proteins
C !
nucleic acids
polysaccharides
lipids
all of the above
Question 13
2 / 2 pts
The biochemical principle that organisms acquire, transform, store, and use
energy requires that cells be able to ________.
convert light into other forms of energy
extract heat from their environment
produce their own energy
use only one form of energy from their environment
C !
extract energy from their environment
Question 14
0 / 2 pts
Change in enthalpy (ΔH) is best defined as ________.
the measure of disorder in a system
the sum of heat absorbed and work done
the pressure change at constant temperature
Correct Answer
the heat content of a system
Y Answered
none of the above
Question 15
2 / 2 pts
During vigorous exercise, hydrogen ions are produced within cells as a result
of increased metabolism. What component of the intracellular buffer would
increase as a result of the increased H+ production?
PO43-
H3PO4
C !
H2PO4-
HPO42-
none of the above
Question 16
2 / 2 pts
Which of the major types of biomolecules is never found in a polymeric form?
C !
lipids
amino acids
nucleotides
carbohydrates
none of the above
Question 17
0 / 2 pts
Which of the following is a major difference between eukaryotic and
prokaryotic cells?
eukaryotic cells are much larger than prokaryotic cells
eukaryotic cells contain a nucleus, prokaryotic cells do not
eukaryotic cells often form multicellular organisms, prokaryotic cells do not
Y Answered
eukaryotic cells contain organelles, prokaryotic cells do not
Correct Answer
all of the above
Question 18
2 / 2 pts
What term is used to describe the exclusion of nonpolar substances from an
aqueous solution?
lipid effect
C !
hydrophobic effect
nonpolar effect
oil droplet effect
amphiphilic effect
Question 19
2 / 2 pts
Urea is a water-soluble product of nitrogen metabolism. How many hydrogen
bonds can one urea molecule donate to surrounding water molecules?
5
2
6
3
C !
4
Question 20
2 / 2 pts
Which of the following would be the strongest acid?
succinic acid, a diprotic acid with pK = 4.21 and 5.64
C !
formic acid, pK = 3.75
acetic acid, pK = 4.76
ammonium ion, pK = 9.25
cannot be determined from the given information
Question 21
2 / 2 pts
Which of the following is an example of the hydrophobic effect?
oil sheens seen on the ocean following an oil spill
the lipid membrane of cells and organelles
protein folding that places hydrophobic amino acids in the interior of the
protein
the separation of salad dressing
C !
all of the above
Question 22
2 / 2 pts
Which of the following molecules contains the most oxidized form of carbon?
acetaldehyde
acetic acid
C !
carbon dioxide
ethanol
ethylene
Question 23
2 / 2 pts
Photosynthetic organisms use energy from the sun to reduce ________ to
________.
formaldehyde; ethanol
C !
CO2; carbohydrates
CO2; ethanol
CO2; oxygen
none of the above
Question 24
2 / 2 pts
Which of the following is the most abundant element in the human body?
oxygen
phosphorous
C !
carbon
nitrogen
none of the above
Question 25
2 / 2 pts
Molecules such as methanol and ethanol are very soluble in water because
________.
C !
they contain O─H groups that can form multiple H-bonds with water
they do not form intermolecular H-bonds
they contain C─H groups that donate H-bonds to water
they tend to avoid contact with each other
they contain C─H groups that accept H-bonds from water
Question 26
2 / 2 pts
Which of the following shows the intracellular buffer?
C !
H2PO4- ⇌ HPO42- + H+
HCO3- ⇌ CO32- + H+
H2CO3 ⇌ HCO3- + H+
HPO42- ⇌ PO43- + H+
H3PO4 ⇌ H2PO42- + H+
Question 27
2 / 2 pts
Which of the biopolymers is correctly paired with its major function?
nucleic acids: energy storage
lipids: information encoding
C !
polysaccharide: energy storage
protein: information encoding
none of the above
Question 28
2 / 2 pts
What is the conjugate acid of H2PO4-?
H2PO4
C !
H3PO4
PO43-
HPO42-
none of the above
Question 29
2 / 2 pts
Which of the following is an example of an amphipathic molecule?
C !
palmitic acid, a fatty acid
adenine, a base found in nucleic acids
glucose, a monosaccharide
serine, an amino acid
none of the above
Question 30
2 / 2 pts
When a non-polar substance is added to water, how do the molecules of
water behave?
the regular hydrogen bond pattern is disrupted resulting in an increase of
entropy
the regular hydrogen bond pattern is disrupted resulting in an increase of
enthalpy
the regular hydrogen bond pattern is disrupted resulting in a decrease of
enthalpy
C !
the regular hydrogen bond pattern is disrupted resulting in a decrease of
entropy
none of the above
Question 31
2 / 2 pts
Fatty acid anions most commonly assemble into ________ in aqueous solution.
liposomes
C !
micelles
lipid bilayers
solvent-filled vesicles
none of the above
Question 32
2 / 2 pts
Which of the following statements about water is not true?
It has a high dielectric constant.
In the liquid state it is only 15% less hydrogen bonded than in the solid state
at 0°C.
It packs in a hexagonal- (honeycomb-) shaped lattice when the temperature
falls below 0°C.
It dissolves salts and polar substances.
C !
It can form two hydrogen bonds per water molecule.
Question 33
2 / 2 pts
An exergonic process ________.
is spontaneous
occurs without the addition of free energy
has a ΔG < 0
will have more products than reactants at equilibrium
C !
all of the above
Question 34
2 / 2 pts
A reaction with a ________ ΔH and a ________ ΔS will never be spontaneous.
positive; positive
negative; positive
C !
positive; negative
negative; negative
none of the above
Question 35
2 / 2 pts
Which of the following molecules would be prevented from readily crossing a
lipid bilayer?
sodium ions
potassium ions
water
glucose
C !
all of the above
Question 36
2 / 2 pts
The second law of thermodynamics states ________.
that spontaneous processes are characterized by the conversion of work to
force
that nonspontaneous processes are characterized by the conversion of order
to disorder
C !
that spontaneous processes are characterized by the overall conversion of
order to disorder
that spontaneous processes are characterized by the conversion of heat to
pressure
none of the above
Question 37
2 / 2 pts
Entropy is used to measure ________.
free energy
temperature
C !
randomness
heat content
all of the above
Question 38
2 / 2 pts
Which of the following functional groups has two hydrogen bond donors and
one hydrogen bond acceptor?
thiol
C !
amine
ester
alcohol
amide
Question 39
2 / 2 pts
The biological classification system categorizes organisms into which of the
following domains?
bacteria and eukarya
prokarya and eukarya
archaea and eukarya
C !
bacteria, archaea and eukarya
bacteria, eukarya and prokarya
Question 40
2 / 2 pts
At any given moment, a single water molecule participates in ________ strong
hydrogen bond(s). The role played by the water molecule is best
characterized as ________.
two; two H-bond acceptor
one; H-bond donor
one; H-bond acceptor
two; two H-bond donor
C !
two; one H-bond donor, one H-bond acceptor
Quiz Score: 76 out of 80
