Biochem Exam 1 Questions And
Answers
Which three cellular components are present in both prokaryotes and eukaryotes? –
RNA, DNA, ribosomes
Phylogeny is –
the science of biological classification based on the evolutionary relationships
between organisms
Taxonomy is –
the science of biological classification based on gross morphology
What are the four most abundant elements in a human body? –
C, N, O, H
The second law of thermodynamics states –
that spontaneous processes are characterized by the overall conversion of order
to disorder
Change in enthalpy (ΔH) is best defined as –
the sum of energy available to do work and energy unavailable to do work
If gas molecules in an enclosed chamber are allowed to enter a second chamber, the
resulting redistribution of gas molecules represents an increase in –
entropy
Consider the reaction A+B --> C+D. After reaching equilibrium at 25°C, the following
concentrations of reactants and products were measured: [A]=10μM, [B]=15μM,
[C]=10μM, [D]=10μM. Calculate ΔG°' for this reaction –
1 kJ/mol
A reaction with a ___________ ΔH and a _________ ΔS will never be spontaneous –
positive, negative
An endergonic reaction with a __________ ΔH and a _________ ΔS can be changed
into an exergonic reaction by decreasing the temperature. –
negative, negative
The ΔG°' for the conversion of glucose 6-phosphate (G6P) to fructose 6-phosphate
(F6P) is +1.7 kJ/mole. In a particular human cell the concentration G6P is 0.8μM and
the concentration of F6P is 1.0μM. Calculate the ΔG' of the reaction as it occurs in this
cell at 37°C. –
, -3.7 kJ/mol
For a reaction with ΔH= 23kJ/mol and ΔS= 22J/K⋅mol, that is carried out at 27°C, the
reaction is –
opposed
Calculate the ΔG for a reaction with ΔH= 20 kJ/mol and ΔS= 20 J/K⋅mol, that is carried
out at 27°C –
14,000 J/mol
A spontaneous process –
All of the above: occurs without the addition of free energy, has a ΔG<0, and is
exergonic
Living organisms –
maintain a steady state
Keq can be determined from the change in standard-state free energy using the
equation –
Keq = e^-ΔG°'/RT
Living organisms are classified as –
open systems
The strongest nonequivalent interactions are –
ionic interactions
Urea is a water-soluble product of nitrogen metabolism. How many hydrogen bonds can
one urea molecule donate to surrounding water molecules? –
4
In a hydrogen bond between a water molecule and another biomolecule –
the partial charge on a hydrogen of the water molecule interacts with the partial
charge on a hydrogen of the other molecule
Which of the following statements about water is not true? –
It can form two hydrogen bonds per water molecule
Amphiphilic (aka amphipathic) molecules –
have both hydrophilic and hydrophobic groups
Which of the following statements about the hydrophobic effect is not true? –
It is caused by hydrophobic molecules interacting strongly with each other
Which of the following is the best explanation for the hydrophobic effect? –
Answers
Which three cellular components are present in both prokaryotes and eukaryotes? –
RNA, DNA, ribosomes
Phylogeny is –
the science of biological classification based on the evolutionary relationships
between organisms
Taxonomy is –
the science of biological classification based on gross morphology
What are the four most abundant elements in a human body? –
C, N, O, H
The second law of thermodynamics states –
that spontaneous processes are characterized by the overall conversion of order
to disorder
Change in enthalpy (ΔH) is best defined as –
the sum of energy available to do work and energy unavailable to do work
If gas molecules in an enclosed chamber are allowed to enter a second chamber, the
resulting redistribution of gas molecules represents an increase in –
entropy
Consider the reaction A+B --> C+D. After reaching equilibrium at 25°C, the following
concentrations of reactants and products were measured: [A]=10μM, [B]=15μM,
[C]=10μM, [D]=10μM. Calculate ΔG°' for this reaction –
1 kJ/mol
A reaction with a ___________ ΔH and a _________ ΔS will never be spontaneous –
positive, negative
An endergonic reaction with a __________ ΔH and a _________ ΔS can be changed
into an exergonic reaction by decreasing the temperature. –
negative, negative
The ΔG°' for the conversion of glucose 6-phosphate (G6P) to fructose 6-phosphate
(F6P) is +1.7 kJ/mole. In a particular human cell the concentration G6P is 0.8μM and
the concentration of F6P is 1.0μM. Calculate the ΔG' of the reaction as it occurs in this
cell at 37°C. –
, -3.7 kJ/mol
For a reaction with ΔH= 23kJ/mol and ΔS= 22J/K⋅mol, that is carried out at 27°C, the
reaction is –
opposed
Calculate the ΔG for a reaction with ΔH= 20 kJ/mol and ΔS= 20 J/K⋅mol, that is carried
out at 27°C –
14,000 J/mol
A spontaneous process –
All of the above: occurs without the addition of free energy, has a ΔG<0, and is
exergonic
Living organisms –
maintain a steady state
Keq can be determined from the change in standard-state free energy using the
equation –
Keq = e^-ΔG°'/RT
Living organisms are classified as –
open systems
The strongest nonequivalent interactions are –
ionic interactions
Urea is a water-soluble product of nitrogen metabolism. How many hydrogen bonds can
one urea molecule donate to surrounding water molecules? –
4
In a hydrogen bond between a water molecule and another biomolecule –
the partial charge on a hydrogen of the water molecule interacts with the partial
charge on a hydrogen of the other molecule
Which of the following statements about water is not true? –
It can form two hydrogen bonds per water molecule
Amphiphilic (aka amphipathic) molecules –
have both hydrophilic and hydrophobic groups
Which of the following statements about the hydrophobic effect is not true? –
It is caused by hydrophobic molecules interacting strongly with each other
Which of the following is the best explanation for the hydrophobic effect? –
