ATP and Energy

Based on the first law of thermodynamics, which of the following statements about a living organism is true?

• The energy content of an organism remains constant throughout its life.
• The organism ultimately must obtain all of the necessary energy for life from its environment.
• The entropy of an organism decreases with time as the organism grows in complexity.

• An organism grows by converting energy into organic matter.

Which of the following is a correct statement based on the first law of thermodynamics?

• Energy cannot be created or destroyed, only transferred or transformed
• The entropy of the universe is decreasing.
• The entropy of the universe is constant.
• Energy cannot be transferred or transformed, only created or destroyed.

Which of the following types of reactions would decrease the entropy within a cell?

• anabolic reactions
• hydrolysis of peptide bonds
• catabolic reactions
• digestion

Living organisms increase in complexity as they grow, resulting in a decrease in the entropy of an organism. How does this relate to the second law of thermodynamics?

• Living organisms do not obey the second law of thermodynamics, which states that entropy must increase with time.
• The complexity is actually associated with greater disorder than the level of disorder associated with the organism at early stages of development.
• As a consequence of growing, organisms cause a greater increase in entropy in their environment than the decrease in entropy associated with their growth.
• Living organisms are able to transform energy into entropy.

In the 1660s, Flemish physician Jan van Helmont grew a willow tree in a pot of soil. He added only water to the pot. At the end of five years, he found that the tree had gained 75 kilograms, but there was very little change in the mass of the soil. Where did the 75 kilograms of biomass in the tree come from?

• The soil in the pot
• The water he added to the soil
• The CO2 from the air
• The energy from sunlight

To which bond in the ATP molecule is nearly all the energy from the sun that is captured by living organisms eventually transferred to?

• A
• B
• C
• D

Which of the following is NOT TRUE about ATP and the process of phosphorylation?

• It is the coupling of the exergonic hydrolysis of ATP to another endergonic reaction.
• Transferring a phosphate from ATP to a protein often forces it to change shape, resulting in cellular work being performed, such as the “walking” of kinesin along a microtubule.
• The addition of an inorganic phosphate (Pi) to ADP to make ATP is an exergonic reaction.
• Once created, ATP must be used quickly, before it spontaneously hydrolyzes into ADP + Pi.

Which of the following molecules is BOTH the primary source of energy AND biomass in most living systems?

• H2O
• CO2
• C6H12O6
• ATP
• O2

Which of the following is the most comprehensive definition of metabolism in living organisms?

• Metabolism depends on a constant supply of energy from food.
• Metabolism manages the increase of entropy in an organism.
• Metabolism refers to the sum of all biochemical pathways involved in synthesis of macromolecules.
• Metabolism consists of all the energy transformation reactions in an organism.

Which of the following processes or reactions are anabolic? Check all that apply.

• Photosynthesis
• ADP + Pi → ATP
• 6CO2 + 6H2O → C6H12O6 + 6O2
• Cellular respiration
• ATP → ADP + Pi