Question 1
2 / 2 pts
Which of the following shows the intracellular buffer?
C !
H2PO4
- ⇌ HPO4
2- + H+
HCO3
- ⇌ CO3
2- + H+
H2CO3 ⇌ HCO3
- + H+
HPO4
2- ⇌ PO4
3- + H+
H3PO4 ⇌ H2PO4
2- + H+
Question 2
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 3
2 / 2 pts
What functional groups are present in the following molecule?
alcohol, amine, amide and carboxylic acid
amine, ketone and carboxylic acid
C !
amine, amide and carboxylic acid
amine and carboxylic acid
none of the above are correct
Question 4
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 5
0 / 2 pts
Which of the following is the most abundant element in the human body?
Y A
oxygen
phosphorous
Correct Answer
carbon
nitrogen
none of the above
Question 6
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 7
2 / 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
eukaryotic cells contain organelles, prokaryotic cells do not
C !
all of the above
Question 8
2 / 2 pts
Which of the following molecules contains the most oxidized form of carbon?
acetaldehyde
acetic acid
C !
carbon dioxide
ethanol
ethylene
Question 9
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 10
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 11
2 / 2 pts
What is the conjugate acid of H2PO4
-?
H2PO4
C !
H3PO4
PO4
3-
HPO4
2-
none of the above
Question 12
2 / 2 pts
Which of the following correctly identifies the progression from individual molecules to a
functioning multi-cellular organism?
molecules, cell, organelle, organ, organism
molecules, cell, organ, organelle, organism
C !
molecules, organelle, cell, organ, organism
molecules, organelle, organ, cell, organism
molecules, organ, organelle, cell, organism
Question 13
2 / 2 pts
In aqueous solution, globules of up to several thousand amphiphilic molecules arranged with the
hydrophilic groups on the surface and the hydrophobic groups buried in the center are called
________.
vacuoles
C !
micelles
bilayers
liposomes
none of the above
Question 14
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 15
2 / 2 pts
Due to the formation of hydrogen bonds, ________ is highly soluble in water.
sodium chloride
carbon dioxide
octane
C !
methanol
cholesterol
Question 16
2 / 2 pts
A molecule that has both a polar and nonpolar region is called ________.
endergonic
C !
amphiphilic
micelleic
a membrane
none of the above
Question 17
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 18
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 19
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 20
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 21
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 22
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 23
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 24
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 25
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 26
2 / 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
C !
the heat content of a system
none of the above
Question 27
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 28
2 / 2 pts
The strongest non-covalent interactions are ________.
dipole-dipole interactions
van der Waals interactions
London dispersion forces
hydrogen bonds
C !
ionic interactions
Question 29
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?
PO4
3-
H3PO4
C !
H2PO4
-
HPO4
2-
none of the above
Question 30
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 31
2 / 2 pts
An endergonic reaction with a ________ ΔH and a ________ ΔS can be changed into an
exergonic reaction by decreasing the temperature.
positive; negative
negative; positive
C !
negative; negative
positive; positive
Question 32
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 33
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 34
2 / 2 pts
Which of the following shows the buffer that is found in the blood stream?
H3PO4 ⇌ H2PO4
2- + H+
C !
H2CO3 ⇌ HCO3
- + H+
HPO4
2- ⇌ PO4
3- + H+
H2PO4
- ⇌ HPO4
2- + H+
HCO3
- ⇌ CO3
2- + H+
Question 35
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 36
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 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
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 39
2 / 2 pts
Which of the following molecules would be prevented from readily crossing a lipid bilayer?
sodium ions
potassium ions
