Mastering Bio 5

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Which of the following is NOT a thermodynamic reason a process or reaction (reactant → product) could be endergonic?

The free energy of the products is higher than the free energy of the reactants.
The process is characterized by a significant loss of entropy.
The process or reaction liberates free energy.
The concentration of reactants and products favors too much product relative to the equilibrium ratio for the process.
The process or reaction liberates free energy.
__________ trap solar energy by pigment systems and convert __________ into more complex cellular materials via __________ chemistry.

Phototrophs; oxygen; isomerization
Phototrophs; carbon dioxide and water; reduction
Chemotrophs; carbon dioxide and water; hydrolysis
Chemotrophs; oxygen; oxidation
Phototrophs; carbon dioxide and water; reduction
Cells maintain themselves in a steady state, with most of their reactions __________. Cells accomplish this by __________.

having K′eq near 1; doing no useful work
far from thermodynamic equilibrium; having a continuous input of matter and energy from their surroundings
relying on an increase in entropy to create a negative ΔG; maintaining a constant temperature
having products and reactants that are the same; violating the second law of thermodynamics
far from thermodynamic equilibrium; having a continuous input of matter and energy from their surroundings
Many biochemical reactions that occur in the cell are nonspontaneous when measured at the biochemical standard state, but are spontaneous inside of the cell. What is the most likely explanation for this difference in spontaneity for the same reaction measured under different conditions?

The concentrations of reactants and products inside the cell favor the products.
The concentrations of reactants inside the cell are lower than the concentration of the products.
Cells violate the second law of thermodynamics.
Cells are closed thermodynamic systems.
The concentrations of reactants and products inside the cell favor the products.
What is the sign of ΔG for the folding process? What about for the unfolding (denaturation) process? How do you know?
Protein folding occurs spontaneously, which means that it is a thermodynamically spontaneous process, so the value for ΔG must be negative. This in turn means that the ΔG value for protein unfolding must be positive because the value of a thermodynamic parameter for the reverse reaction always has the same numeric value but the opposite sign.
What is the sign for ΔS for the folding process? What about for the unfolding (denaturation) process? How do you know?
Protein folding results in greater order, so the ΔS value will be negative. That means, in turn, that the ΔS value for denaturation will be positive.
Will the contribution of ΔS to the free energy change be positive or negative?

The contribution of ΔS to the free energy change will be positive for protein folding.
The contribution of ΔS to the free energy change will be negative for protein folding.
The contribution of ΔS to the free energy change will be positive for protein folding.
What are the main kinds of bonds and interactions that must be broken or disrupted if a folded polypeptide is to be unfolded?
Select the five options.

van der Waals interactions
hydrogen bonds
ionic bonds
carbon-nitrogen bonds
disulfide bonds
carbon-carbon bonds
hydrophobic interactions
carbon-oxygen bonds
van der Waals interactions
hydrogen bonds
ionic bonds
disulfide bonds
hydrophobic interactions
Why do heat and extremes of pH cause unfolding?
Select all that apply.

Heating adds energy to the system, thereby disrupting both primary and secondary structures of protein.
Extremes of pH cause polarization of the protein molecule, thereby disrupting hydrophobic interactions.
Extremes of pH provide high concentration of either acid or base that causes the hydrolysis of disulfide bonds.
Heating adds energy to the system, making it more difficult for the noncovalent bonds to maintain the polypeptide in its native conformation.
Extremes of pH cause changes in the ionization or protonation state of some functional groups, thereby disrupting both ionic and hydrogen bonds.
Heating adds energy to the system, making it more difficult for the noncovalent bonds to maintain the polypeptide in its native conformation.
Extremes of pH cause changes in the ionization or protonation state of some functional groups, thereby disrupting both ionic and hydrogen bonds.
What can be said about an endothermic reaction with a negative entropy change?
View Available Hint(s)
The reaction is
spontaneous at all temperatures.
spontaneous at high temperatures.
spontaneous at low temperatures.
spontaneous in the reverse direction at all temperatures.
nonspontaneous in either direction at all temperatures.
spontaneous in the reverse direction at all temperatures.
What can be said about an exothermic reaction with a negative entropy change?
View Available Hint(s)
The reaction is
spontaneous at all temperatures.
spontaneous at high temperatures.
spontaneous at low temperatures.
spontaneous in the reverse direction at all temperatures.
nonspontaneous in either direction at all temperatures.
spontaneous at low temperatures.
If ΔH = -70.0 kJ and ΔS = -0.200 kJ/K , the reaction is spontaneous below a certain temperature. Calculate that temperature.
Express your answer numerically in kelvins.
350K
1. In a biogeochemical cycle, a chemical element spends time in different places, called _______.
2. As a chemical element moves through a biogeochemical cycle, it moves between "bio" and "geo." The "bio" in biogeochemical refers to biotic reservoirs, or ________.
3. The "geo" in biogeochemical refers to ______--specifically, to the abiotic reservoirs where a chemical element can be found.
4. In the terrestrial carbon cycle, the abiotic reservoir from which living organisms directly obtain their carbon is ___________
5. Carbon moves from an abiotic reservoir to living organisms during the process of ___________.
6. Carbon moves from living organisms to an abiotic reservoir during the process of ______.

reservoirs
living organisms.
Earth
the atmosphere.
photosynthesis
cellular respiration
1. In a biogeochemical cycle, a chemical element spends time in different places, called reservoirs.
2. As a chemical element moves through a biogeochemical cycle, it moves between "bio" and "geo." The "bio" in biogeochemical refers to biotic reservoirs, or living organisms.
3. The "geo" in biogeochemical refers to Earth--specifically, to the abiotic reservoirs where a chemical element can be found.
4. In the terrestrial carbon cycle, the abiotic reservoir from which living organisms directly obtain their carbon is the atmosphere.
5. Carbon moves from an abiotic reservoir to living organisms during the process of photosynthesis.
6. Carbon moves from living organisms to an abiotic reservoir during the process of cellular respiration.
Which of the activities listed below could help limit global warming by slowing the increase in atmospheric carbon dioxide levels?
Select all that apply.
View Available Hint(s)

replacing fossil fuels with nuclear energy
using more electrical appliances and cars
burning vegetation to clear land for agriculture
limiting soil erosion so organic matter takes longer to decompose
choosing a fuel-efficient car, or bicycling to school or work
cutting down forests to build houses
limiting soil erosion so organic matter takes longer to decompose
choosing a fuel-efficient car, or bicycling to school or work
replacing fossil fuels with nuclear energy
Which of these is exhibiting kinetic energy?

the high-energy phosphate bonds of a molecule of ATP
a rock on a mountain ledge
an archer with a flexed bow
a person sitting on a couch while watching TV
a space station orbiting Earth
a space station orbiting Earth
"Conservation of energy" refers to the fact that _____.

no chemical reaction is 100 percent efficient
the net amount of disorder is always increasing
the entropy of the universe is always increasing
energy cannot be created or destroyed but can be converted from one form to another
if you conserve energy you will not be as tired
energy cannot be created or destroyed but can be converted from one form to another
Chemical energy is a form of _____ energy.

potential
kinetic
motion
entropic
heat
potential
In your body, what process converts the chemical energy found in glucose into the chemical energy found in ATP?

potentiation
redox
digestion
cellular respiration
anabolism
cellular respiration
Which of these are by-products of cellular respiration?

carbon dioxide and water
ATP and carbon dioxide
heat, carbon dioxide, and water
ATP, carbon dioxide, and water
glucose, carbon dioxide, and wate
heat, carbon dioxide, and water
Match
bioluminescence:
mechanical work:
heat:
concentration work:
synthetic work:
electrical work:

glowing fungi
muscle contraction
maintaining body temperature
accumulation of substances in a cell
carbon fixation
nerve impulse conduction
bioluminescence: glowing fungi
mechanical work: muscle contraction
heat: maintaining body temperature
concentration work: accumulation of substances in a cell
synthetic work: carbon fixation
electrical work: nerve impulse conduction
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