BIOC 385 Exam 1 || Questions and 100% Verified Answers.
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Course
BIOC 385
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BIOC 385
AL 1.1 - what is the difference between actual change in free energy (delta G) and standard change in free energy (delta G knot) with regard to the spontaneity of the cell. correct answers Delta G knot can be used to predict the spontaneity of a reaction under standard conditions, which are 1 atm, ...
BIOC 385 Exam 1 || Questions and 100% Verified Answers.
AL 1.1 - what is the difference between actual change in free energy (delta G) and standard
change in free energy (delta G knot) with regard to the spontaneity of the cell. correct answers
Delta G knot can be used to predict the spontaneity of a reaction under standard conditions,
which are 1 atm, 298K and all reactants and products are initially set at [1M]. Under these
conditions, the reaction will be spontaneous if delta G knot <0 as defined by.
Delta G knot = -RT lnKeq. Under cellular conditions, the actual change in free energy (delta G)
is the sum of delta G knot and a function of the mass action ratio, which includes concentrations
of products and reactant under steady state conditions (RT lnQ)
AL 1.2 Name three processes affecting enzyme bioavailability and three mechanisms controlling
efficiency correct answers Affecting enzyme bioavailability:
RNA synthesis (gene transcription)
RNA processing
Protein synthesis (amount of enzyme produced)
Protein degradation
Protein targeting
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
What is the overall balanced reaction for the light reactions of photosynthesis? correct answers 2
H2O + 8 photons + 2 NADP+ + 3 ADP + 3 Pi ---> O2 + 2 NADPH + 3 ATP
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
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 of the following best defines the first law of thermodynamics? correct answers Total
amount of energy in the universe is a constant.
Review the figure below. Shared intermediates are used so effectively in coupled reactions
because they correct answers NONE of the answers are correct ( decrease the value of Q, allow
products to diffuse through the membrane to increase concentration gradient, increase product
diffusion out of the active site, or increase the value of delta G)
, Select the TWO true statements from the list below regarding the structure and function of
enzymes. correct answers 1. Enzymes increase the rates of biochemical reactions without
changing the equilibrium constant.
2. Enzyme cofactors can increase the chemical functionality of enzymes, which are otherwise
limited by the R groups.
R is the highly active form of an allosteric enzyme and T is the less active form of enzyme. What
would happen to [T]/[R] if substrate concentration is decreased? correct answers Increase
The O2 generated from photosynthesis is dervied from correct answers water molecules that
directly reduce PSII
How can unfavorable reaction (delta G > 0) still occur in a metabolic pathway? correct answers
Link it to a favorable reaction
Paraquat is an effective herbicide the kills plants by disrupting the photosynthetic electron
transport system. Why then was the spraying of marijuana fields with paraquat discontinued in
the 1980's? correct answers None of these statements are correct.
(It was stopped because the governments of the countries involved could not decide who should
pay for it.
It was discovered that aerial spraying of paraquat is very dangerous to livestock and should never
be used for crop management because it inhibits PSI in cows.
It was known at the time that marijuana was resistant to paraquat so it was a waste of money.
It was not discontinued, in fact paraquat is still used today to destroy marijuana crops in
Colorado.)
Energy conversion in living systems is required for what three types of work? correct answers
osmotic work, chemical work, mechanical work
Which THREE of the following statements about autotrophs and heterotrophs on Earth are
TRUE? correct answers Heterotrophs depend on autotrophs for conversion of light energy to
chemical energy.
Heterotrophs are dependent on autotrophs to generate O2 from H2O in order to support aerobic
respiration
The majority of autotrophs on Earth require aerobic respiration in order to survive.
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 1. The sun comes up
2. 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.
3. 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.
4. 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.
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