BIOL 1009 Exam 2 Study Questions With 100% Verified Answers

A reaction has a ∆G of -5.6 kcal/mol. Which of the following would most likely be TRUE? - correct answers The reaction would result in an increase in entropy (S) and a decrease in the energy content (H) of the system. T is the temperature in Kelvin Which term precisely describes the cellular process of breaking down large molecules into smaller ones? - correct answers catabolism Which of the following statements is FALSE? - correct answers Hydrolysis of ATP to form ADP and inorganic phosphate is a highly endergonic reaction A consequence of the fact that Gibb's free energy must decrease in a spontaneous reaction is - correct answers that a given reaction may proceed spontaneously in both directions, due to the fact that different reactant and product molecules will have slightly different energies. Which of the following statements is representative of the second law of thermodynamics? - correct answers Cells require a constant input of energy to maintain their high level of organization. A chemical reaction that has a positive ∆G is correctly described as - correct answers endergonic The hydrolysis of ATP to form ADP and Pi is - correct answers highly exergonic The synthesis of polymers from their constituent monomers occurs during - correct answers anabolism Energy that goes to increase the entropy of the universe is - correct answers no longer available to perform work Why is ATP an important molecule in metabolism? - correct answers It provides energy coupling between exergonic and endergonic reactions 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? - correct answers As a consequence of growing, organisms create more disorder in their environment than the decrease in entropy associated with their growth. The rate of flow of materials through a metabolic pathway can be altered by - correct answers -changing the activity level(s) of one or more of the enzymes that catalyze steps in that pathway. -altering the amount of substrate for the reaction -altering the amount of product for the reaction (all of these answers are correct) Which of the following is considered an open system? - correct answers a plant cell with a strong cell wall a clam an animal cell (all of these answers are correct) How does energy from ATP allow some of the reactions of anabolism to occur? - correct answers -Energy from ATP is used to increase the potential energy of a reactant molecule, such that the total free energy of the reactant molecules is now greater than the total free energy of the product molecules that would be formed by the reaction. -Some of the energy from a high-energy covalent bond in the ATP molecule is used to form a high-energy covalent bond in a substrate molecule. -A phosphate group is transferred from ATP to a reactant molecule, raising the energy level of that reactant molecule. (All of these answers are correct) When chemical, transport or mechanical work is done by an organism, what happens to the heat generated? - correct answers It is lost to the environment. Anabolism results in the production of molecules with high amounts of potential energy stored in their chemical bonds. How can the reactions of anabolism occur without violating the requirement that all reactions must result in a decrease in free energy? - correct answers B) Energy from ATP is often used to help combine an exergonic reaction with a reaction that would otherwise be endergonic. A) A reaction that would otherwise be endergonic is combined with an exergonic reaction. The overall reaction than occurs in multiple steps, each of which involves an exergonic reaction. (Both A&B) When ATP releases some energy, it also releases inorganic phosphate. What purpose, if any, does this serve in the cell? - correct answers It can be added to other molecules in order to activate them. The mathematical expression for the change in the free energy of a system is ∆G = ∆H - T∆S. Which of the following is (are) TRUE? - correct answers ∆G is the change in free energy. ∆S is the change in entropy. The breakdown of polymers to their constituent monomers occurs during - correct answers catabolism The hydrolysis of ATP: ATP + H2O → ADP + Pi is exergonic, with a ∆G of -7.3 kcal/mol under standard conditions. What is the source of the 7.3 kcal/mol released in this reaction? - correct answers the difference between the potential energy in the bonds of ATP and the water molecule, minus the potential energy in the bonds of ADP and Pi. In other words: (potential energy in bonds of ATP + potential energy in bonds of H2O) - (potential energy in bonds of ADP + potential energy in bonds of Pi) = 7.3 kcal/mol Most cells cannot harness heat to perform work because - correct answers temperature is usually uniform throughout a cell. How do living organisms create macromolecules, organelles, cells, tissues, and complex higher-order structures? - correct answers Living organisms create order locally, but the energy transformations generate waste heat that increases the entropy of the universe as a whole. If an enzyme in solution is saturated with substrate, the most effective way to obtain a faster yield of products is to - correct answers add more of the enzyme. A solution of protein at room temperature does not readily decompose to form a solution of amino acids because - correct answers The activation energy barrier cannot be surmounted. Which of the following is the best explanation for how enzymes speed up the rates of reactions? - correct answers Enzymes lower the energy required for reactant molecules to reach their transition state. Enzymes do not alter the free or total energies of the reactant or product molecules. The mechanism by which the end product of a metabolic pathway inhibits an enzyme that catalyzes an earlier step in the pathway is known as - correct answers feedback inhibition For the reaction depicted in the figure below, the activation energy barrier for converting C and D to A and B via the non-catalyzed reaction is represented by - correct answers arrow E Increasing the substrate concentration in an enzymatic reaction could overcome which of the following? - correct answers competitive inhibition