BIO 105 Final Review Part 3

Which of the following correctly states the relationship between anabolic and catabolic pathways?

• Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways.

• Energy derived from catabolic pathways is used to drive the breakdown of organic molecules in anabolic pathways.

• Degradation of organic molecules by anabolic pathways provides the energy to drive catabolic pathways.

• Catabolic pathways produce usable cellular energy by synthesizing more complex organic molecules.

Which of the following states the relevance of the first law of thermodynamics to biology?

• Energy can be freely transformed among different forms as long as the total energy is conserved.

• Living organisms must increase the entropy of their surroundings.

• Because living things consume energy, the total energy of the universe is constantly decreasing.

• Energy is destroyed as glucose is broken down during cellular respiration

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NGSS.HS-LS1-7

NGSS.HS-LS1-5

According to the second law of thermodynamics, which of the following is true?

• The decrease in entropy associated with life must be compensated for by increased entropy in the environment in which life exists.

• The total amount of energy in the universe is constant.

• Energy conversions increase the order in the universe.

• The entropy of the universe is constantly decreasing.

An exergonic (spontaneous) reaction is a chemical reaction that __________

• occurs only when an enzyme or other catalyst is present

• is common in anabolic pathways

• releases energy when proceeding in the forward direction

• cannot occur outside of a living cell

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NGSS.HS-PS1-4

Metabolic pathways in cells are typically far from equilibrium. Which of the following processes tend(s) to keep these pathways away from equilibrium?

• the continuous removal of the products of a pathway to be used in other reactions

• an input of free energy from outside the pathway

• an input of heat from the environment

• The first and second listed responses are correct.

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NGSS.HS-LS1-7

Which of the following is changed by the presence of an enzyme in a reaction?

• the G value for the products

• the G value for the reactants

• the sign of ΔG

• the activation energy

How do enzymes lower activation energy?

• by increasing reactivity of products

• by bringing reactants into close proximity

• by harnessing heat energy to drive the breakage of bonds between atoms

• by adding energy to the reaction

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NGSS.HS-PS1-4

A plot of reaction rate (velocity) against temperature for an enzyme indicates little activity at 10°C and 45°C, with peak activity at 35°C. The most reasonable explanation for the low velocity at 10°C is that __________.

• the enzyme was denatured

• there is too little activation energy available and the molecules move slowly

• the substrate becomes a competitive inhibitor at lower temperature

• the hydrogen bonds that define the structure of the enzyme's active site are unstable

Which of the following statements about enzymes is INCORRECT?

• An enzyme lowers the activation energy of a chemical reaction.

• An enzyme is very specific in terms of the substrate to which it binds.

• Most enzymes are proteins.

• An enzyme is consumed during the reaction it catalyzes.

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NGSS.HS-PS1-5

Which of the following statements about the active site of an enzyme is correct?

• The active site allows the reaction to occur under the same environmental conditions as the reaction without the enzyme.

• The active site may resemble a groove or pocket in the surface of a protein into which the substrate fits.

• The structure of the active site is not affected by changes in temperature.

• The active site has a fixed structure (shape).