Biology, Eighth Edition (Raven)

Chapter 6: Energy and Metabolism

Post Test

How does the energy of sunlight enter into biological systems? (p. 106)
A)It increases the kinetic energy of the molecules it contacts.
B)It oxidizes organic molecules in a redox reaction.
C)It allows the conversion of simple molecules into complex ones.
D)It breaks the bonds between carbon and hydrogen.
E)It is converted from potential to kinetic energy during photosynthesis.
During an endergonic reaction (p. 109)
A)Disorder of the individual molecules of the reaction is increased.
B)The amount of entropy in a system is decreased.
C)The ΔG of the overall reaction is negative.
D)All of the above occurs.
E)None of the above occurs.
The formation of ATP from ADP and phosphate is analogous to (p. 110)
A)Breaking down glucose to get its energy.
B)Climbing stairs up a slide and then going down it.
C)The flowing of water from the top of a waterfall to a pool below.
D)The priming of a mouse trap by fastening the trap wire after tightening its spring.
E)Absorption of sunlight by a plant pigment.
The active site of an enzyme which breaks down fatty acids is most likely (p. 112)
A)Dominated by polar amino acid side chains (R-groups).
C)Rich in nonpolar covalent bonds found in hydrocarbons.
D)Rich in acidic R-groups.
E)Rich in basic R-groups.
Why does the activity of an enzyme decline symmetrically from the optimal pH on either side, rather than showing a rapid decline as temperature increases from the optimum? (Fig 6.11) (p. 114)
A)Hydrogen bonds, which are most susceptible to heat, pull apart suddenly but the covalent bonds in disulfide linkages are broken down during pH changes in either direction.
B)Enzymes work best at around 40°C but are evolutionarily tuned to function at a variety of pH levels.
C)Only heat can denature an enzyme.
D)The acids and bases hydrolyze the amino acids at the same rate.
E)Ionization changes in acid R-groups on one side of the optimum are offset about equally for those changes in basic R-groups on the other side, disrupting ionic stabilization of the tertiary structure.
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