The study of biochemistry attempts to explain ANS: biological processes at the molecular and cellular
level.
The __________ differentiates amino acids from one another. ANS: side chains attached to the central
carbon
If the concentration of aspartate in the cell decreased, what would be the predicted outcome? ANS:
decreased concentration of fumarate
Plasmids are small, circular DNA molecules that are used in which of the following? ANS: gene cloning
A hydrogen bond can best be described as a ANS: weak noncovalent interaction.
Given a DNA sequence of -CAT-, what is the complementary sequence in mRNA? ANS: -5-GUA-3
Bioinformatics shows that 98% of human DNA is identical to that of chimpanzees. If human DNA
contains 3.2 billion nucleotides, how many nucleotides are different between the two species? ANS: 64
million
Highly conserved gene sequences that encode proteins with the same function in different organisms
are called __________ genes. ANS: orthologous
In DNA the phosphate groups are on the outside of the helix. Why does this stabilize the structure?
ANS: ionic interactions with the solvent
What is the cause of the overall negative charge of a molecule of DNA? ANS: the phosphate backbone
,The DNA double helix is stabilized by the interactions between nucleotides because of __________
between nucleotides. ANS: pi-pi stacking
What side products of pyruvate are being converted into alcohol and carbon dioxide by yeast? ANS:
CO2 and NAD+
A requirement for a covalent bond to form between two atoms is that ANS: there are unpaired
electrons on each atom.
The correct name for the VSEPR arrangement around a carbon in methane is ANS: tetrahedral.
Cell signaling and cell membranes are examples of functions performed by which biomolecule? ANS:
fatty acid
The figure below shows an example of which functional group? ANS: phosphoryl
Triacylglycerols are neutral molecules made of ANS: three fatty acid esters covalently linked to glycerol.
Vitamin B2 is a metabolite. Lack of vitamin B2 can lead to blurred vision and a swollen tongue. Vitamin
B2 has such a strong effect on health because metabolites ANS: are the catalysts that drive biochemical
reactions necessary for life-sustaining processes
Which of the following is the correct solar energy reaction that takes place on the sun? ANS: -4 H -> 4He
What is the final molecule made from the oxidation of H2O by solar energy? ANS: glucose
The difference between an oxidation reaction and a reduction reaction is that oxidation is the
__________ and reduction is the __________. ANS: loss of electrons; gain of electrons
, Which of the following is an example of a system? ANS: a test tube with reaction components
A hot pack on your arm is an example of what kind of system? ANS: closed
The combustion of gasoline is considered exothermic because heat is ANS: transferred from the system
to the surroundings.
The change in entropy of a system is a function of a change in ANS: enthalpy and temperature.
If a reaction has a delta h>0 and a delta s<0 , then __________ and the reaction is __________ at all
temperatures. ANS: delta G>0; nonspontaneous
If the equilibrium constant (Keq) is greater than 1, which direction will the reaction proceed? ANS:
spontaneously to products
Under what conditions could a biological reaction spontaneously proceed to reactants if the delta G>0?
ANS: Product concentrations are greater than reactant concentrations.
The transfer of a phosphate from ATP to another molecule produces a(n) ANS: highly reactive
intermediate.
Under steady-state conditions in a mammalian cell, the adenine nucleotide concentrations are [ATP] =
3.3 mM, [ADP] = 1.2 mM, and [AMP] = 0.2 mM. What is the energy charge of this cell? ANS: 0.83
Organisms on Earth cannot easily exist at temperatures below because at that temperature ANS: ice
crystals form in the organism.