BIOC 385 Exam 1 || with 100% Error-free Answers.
2-phosphoglycerate(2PG) is converted to phosphoenolpyruvate (PEP) by the enzyme enolase.
The standard free energy change(deltaGo') for this reaction is +1.7 kJ/mol. If the cellular
concentrations are 2PG = 0.5 mM and PEP = 0.1 mM, what is the free energy change at 37 oC
for the reaction 2PG ↔ PEP? correct answers -2.4 KJ/mol
Which statement below most accurately describes catabolic and anabolic pathways? correct
answers Catabolic pathways degrade molecules and anabolic pathways synthesize new
molecules.
Experimental evidence based on measuring bond energies between DNA strands using all
combinations of G, C, A, and T stacked bases demonstrates that the DNA double helix is
stabilized by noncovalent interactions between nucleotides owing to __________ . correct
answers Pi-Pi stacking
In the figure below, which state of matter has the highest entropy? correct answers Gas phase
Binding of glucose to hexokinase causes a conformational change in the enzyme. This is an
example of the __________ model of enzyme catalysis. correct answers Induced fit
The Biosphere 2 project, in Tucson, Arizona, was an experiment involving a large sealed
terrarium with humans and photosynthetic plants living in balance. Why did the project have to
be interrupted after only a few months? correct answers Levels of CO2 rose to dangerous levels
How can an energetically unfavorable reaction occur in a metabolic pathway? correct answers
Link it to an energetically favorable reaction
If the equilibrium constant (Keq) is greater than 1, which direction will the reaction proceed?
correct answers Spontaneously to products
As shown below, some metabolic pathways use enzymes that are colocalized in membranes to
facilitate reaction rates. Shared intermediates are used so effectively in these types of coupled
reactions because they ________________. correct answers facilitate products being used as
reactants without diffusing away.
Which of the following best defines the first law of thermodynamics? correct answers Total
amount of energy in the universe is a constant
Hydrogen bonds form between hydrogen and _______________ or hydrogen and
______________. correct answers Oxygen, nitrogen
The example of water freezing into ice is an example of _______________. correct answers A
decrease in the entropy of the system
Amino acids are the building blocks for which biomolecules? correct answers Proteins
, Which of the following is the correct formula for glucose? correct answers C6H12O6
In the five steps used by photosynthetic organisms to convert solar energy into chemical energy,
which molecules store the solar energy before sugar synthesis? correct answers ATP and
NADPH
Which two functional groups are involved in producing a peptide bond? correct answers Amino
and carboxyl
Some Calvin Cycle enzymes contain disulfide bonds that must be reduced through a mechanism
involving thioredoxin in order for the enzyme to be active in sunlight. What is the name of the
key regulatory protein that inactivates these same Calvin Cycle enzymes by oxidation when the
sun goes down? correct answers There is no regulatory protein that oxidizes these Calvin cycle
enzymes; oxidation is spontaneous
Paraquat is an effective herbicide that kills plants by disrupting the photosynthetic electron
transport system. Why then was the spraying of marijuana fields with paraquat discontinued in
the 1980s? correct answers It was discontinued because paraquat contaminated marijuana was
being imported into the US and was thought to cause lung damage
Resonance energy transfer from one chlorophyll in the photosystems results in______________.
correct answers A neighboring chlorophyll in an excited state
The term greenhouse effect refers to the idea that_________________. correct answers The
temperature of the earth is increasing because of heat trapped by gasses such as CO2
Put the following steps in photosynthesis in the correct order to generate 2 NADPH and 3 ATP
following the absorption of 8 photons and return of 12 H+ from the thylakoid space to the
stroma. correct answers The sun comes up. PSII absorbs 4 photons leading to photooxidation of
4 chlorophyll molecules and oxidation of 2 H2O to replace the 4 e- in chlorophyll and release 4
H+ into the thylakoid lumen. Oxidation of pheophytin initiates a series of redox reactions
culminating in the reduction of 4 plastocyanin and translocation of 8 H+ across the thylakoid
membrane. PSI absorbs 4 photons leading to the photooxidation of 4 plastocyanin and initiation
of a series of redox reactions culminating in the reduction of 2 NADP+ to yield 2 NADPH. A
total of 12 H+ enter the chloroplast ATP synthase to generate 3 ATP when they return to the
stroma and induce conformational changes in the headpiece of the complex.
Heme and chlorophyll have similar overall structures. What is common between the two
molecules? correct answers Polycyclic planar structure
Which glycan is a major component of plant cell walls? correct answers Cellulose
Which enzyme does penicillin target in bacteria? correct answers Transpeptidase
What is the product of cellulose cleavage by cellulase? correct answers Cellotetraose
2-phosphoglycerate(2PG) is converted to phosphoenolpyruvate (PEP) by the enzyme enolase.
The standard free energy change(deltaGo') for this reaction is +1.7 kJ/mol. If the cellular
concentrations are 2PG = 0.5 mM and PEP = 0.1 mM, what is the free energy change at 37 oC
for the reaction 2PG ↔ PEP? correct answers -2.4 KJ/mol
Which statement below most accurately describes catabolic and anabolic pathways? correct
answers Catabolic pathways degrade molecules and anabolic pathways synthesize new
molecules.
Experimental evidence based on measuring bond energies between DNA strands using all
combinations of G, C, A, and T stacked bases demonstrates that the DNA double helix is
stabilized by noncovalent interactions between nucleotides owing to __________ . correct
answers Pi-Pi stacking
In the figure below, which state of matter has the highest entropy? correct answers Gas phase
Binding of glucose to hexokinase causes a conformational change in the enzyme. This is an
example of the __________ model of enzyme catalysis. correct answers Induced fit
The Biosphere 2 project, in Tucson, Arizona, was an experiment involving a large sealed
terrarium with humans and photosynthetic plants living in balance. Why did the project have to
be interrupted after only a few months? correct answers Levels of CO2 rose to dangerous levels
How can an energetically unfavorable reaction occur in a metabolic pathway? correct answers
Link it to an energetically favorable reaction
If the equilibrium constant (Keq) is greater than 1, which direction will the reaction proceed?
correct answers Spontaneously to products
As shown below, some metabolic pathways use enzymes that are colocalized in membranes to
facilitate reaction rates. Shared intermediates are used so effectively in these types of coupled
reactions because they ________________. correct answers facilitate products being used as
reactants without diffusing away.
Which of the following best defines the first law of thermodynamics? correct answers Total
amount of energy in the universe is a constant
Hydrogen bonds form between hydrogen and _______________ or hydrogen and
______________. correct answers Oxygen, nitrogen
The example of water freezing into ice is an example of _______________. correct answers A
decrease in the entropy of the system
Amino acids are the building blocks for which biomolecules? correct answers Proteins
, Which of the following is the correct formula for glucose? correct answers C6H12O6
In the five steps used by photosynthetic organisms to convert solar energy into chemical energy,
which molecules store the solar energy before sugar synthesis? correct answers ATP and
NADPH
Which two functional groups are involved in producing a peptide bond? correct answers Amino
and carboxyl
Some Calvin Cycle enzymes contain disulfide bonds that must be reduced through a mechanism
involving thioredoxin in order for the enzyme to be active in sunlight. What is the name of the
key regulatory protein that inactivates these same Calvin Cycle enzymes by oxidation when the
sun goes down? correct answers There is no regulatory protein that oxidizes these Calvin cycle
enzymes; oxidation is spontaneous
Paraquat is an effective herbicide that kills plants by disrupting the photosynthetic electron
transport system. Why then was the spraying of marijuana fields with paraquat discontinued in
the 1980s? correct answers It was discontinued because paraquat contaminated marijuana was
being imported into the US and was thought to cause lung damage
Resonance energy transfer from one chlorophyll in the photosystems results in______________.
correct answers A neighboring chlorophyll in an excited state
The term greenhouse effect refers to the idea that_________________. correct answers The
temperature of the earth is increasing because of heat trapped by gasses such as CO2
Put the following steps in photosynthesis in the correct order to generate 2 NADPH and 3 ATP
following the absorption of 8 photons and return of 12 H+ from the thylakoid space to the
stroma. correct answers The sun comes up. PSII absorbs 4 photons leading to photooxidation of
4 chlorophyll molecules and oxidation of 2 H2O to replace the 4 e- in chlorophyll and release 4
H+ into the thylakoid lumen. Oxidation of pheophytin initiates a series of redox reactions
culminating in the reduction of 4 plastocyanin and translocation of 8 H+ across the thylakoid
membrane. PSI absorbs 4 photons leading to the photooxidation of 4 plastocyanin and initiation
of a series of redox reactions culminating in the reduction of 2 NADP+ to yield 2 NADPH. A
total of 12 H+ enter the chloroplast ATP synthase to generate 3 ATP when they return to the
stroma and induce conformational changes in the headpiece of the complex.
Heme and chlorophyll have similar overall structures. What is common between the two
molecules? correct answers Polycyclic planar structure
Which glycan is a major component of plant cell walls? correct answers Cellulose
Which enzyme does penicillin target in bacteria? correct answers Transpeptidase
What is the product of cellulose cleavage by cellulase? correct answers Cellotetraose
