Chapter 6 adaptive quizzing

Imagine that you discover a microbial deep-sea organism that can derive energy from hydrogen gas (H₂). In addition, this microbe can synthesize organic compounds from carbon-containing inorganic molecules in the ocean. This microbe is a:

• phototroph.

• photoheterotroph.

• chemoheterotroph.

• chemoautotroph.

• photoautotroph.

Carbon-carbon covalent bonds, such as the ones in carbohydrates and lipids, are _____ and have _____.

• strong; a lot of kinetic energy

• strong; a lot of potential energy

• weak; a lot of potential energy

• weak; little potential energy

• strong; little kinetic energy

In chemical reactions, most of the entropy increase occurs as:

• ATP production.

• heat.

• glycolysis.

• electrical energy.

• chemical energy.

Nearly all cells use ATP as their primary energy source. This is evidence that:

• fossil fuels are composed of ATP.

• many different alternative energy sources that may have been present during the evolutionary history of life have disappeared.

• ATP evolved recently (in the last 100 years) as a potential source of energy and spread rapidly throughout the living world.

• the use of ATP by cells evolved early in the history of life and has been conserved over time.

Escherichia coli bacteria in your colon are categorized as:

• chemoautotrophs.

• photoheterotrophs.

• photoautotrophs.

• chemoheterotrophs

Which organisms are considered heterotrophs?

• most bacteria and dogs

• dogs only

• most bacteria only

• Plants only

• hydrogen bacteria only

Consider the refrigerator in your kitchen. Based on what you know about the first and second laws of thermodynamics, how does a refrigerator most likely work?

• A refrigerator both destroys any heat in its interior or in the food it contains, and creates new energy in the form of cold.

• A refrigerator removes the potential energy contained within food.

• A refrigerator creates new energy, although it is in the form of cold rather than heat.

• A refrigerator destroys any heat in its interior or in the food it contains.

• A refrigerator removes heat from its interior and transports this energy outside, into the kitchen.

Which of these equations is/are endergonic?

Equation 1: ATP + H₂O → ADP + P_i ΔG₁ = −7 kcal/mol

Equation 2: phosphoenolpyruvate + H₂O → pyruvate + P_i ΔG₂ = −14.8 kcal/mol

Equation 3: glucose + P_i → glucose-6-phosphate + H₂O ΔG₃ = +3.3 kcal/mol

Equation 4: ADP + P_i → ATP + H₂O ΔG₄ = +7 kcal/mol

• Equations 1 and 2

• Equations 3 and 4

• Equations 1 and 3

• Equations 2 and 3

• Equations 1 and 4

The Michaelis–Menten model is an interpretation of:

• how the rate of an enzyme-catalyzed biochemical reaction changes as enzyme concentration changes.

• how the rate of an enzyme-catalyzed biochemical reaction changes as substrate concentration changes.

• the way in which enzyme cofactors influence the K_m of reactions.

• why all enzyme-catalyzed biochemical reactions have the same absolute maximum enzyme concentration.

• how the substrate concentration in an enzyme-catalyzed biochemical reaction can affect the enzyme concentration.

Suppose that, in a given reaction, the enthalpy (H) increases by 10 units, and the disorder (TS) increases by 12 units. Would this reaction be considered spontaneous?

• Yes

• No