LIFE 120 Midterm 2 Questions and Answers (Study Guide) Complete Guide to Prepare for Exams.

Practice question 1) What is the term for metabolic pathways that release stored energy by breaking down complex molecules? a. fermentation pathways b. anabolic pathways c. thermodynamic pathways d. catabolic pathways e. bioenergetic pathways 2) The molecule that functions as the reducing agent (electron donor) in a redox or oxidation-reduction reaction a. neither gains nor loses electrons, but gains or loses potential energy. b. gains electrons and loses potential energy. c. gains electrons and gains potential energy. d. loses electrons and loses potential energy. e. loses electrons and gains potential energy. 3) Whenever energy is transformed, there is always an increase in the a. entropy of the universe. b. free energy of the system. c. free energy of the universe. d. entropy of the system. e. enthalpy of the universe. 4) The mechanism in which the end product of a metabolic pathway inhibits an earlier step in the pathway is most precisely described as a. noncooperative inhibition. b. metabolicinhibition. c. reversible inhibition. d. allostericinhibition. e. feedbackinhibition. 5) Which of the following statements describes NAD+? a. NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. b. NAD+ is oxidized by the action of hydrogenases. c. In the absence of NAD+, glycolysis can still function. d. NAD+ has more chemical energy than NADH. e. NAD+ can donate electrons for use in oxidative phosphorylation. 6) Which of the following statements describes NADH? a. NADH is required for glycolysis to function. b. NADH is oxidized to NAD+ at the electron transport chain and in the fermentation. c. NADH is reduced to NAD+ by the action of hydrogenases. d. NADH has less chemical energy than NAD+. e. NADH can accept electrons for use in oxidative phosphorylation. 7) Where does glycolysis take place in eukaryotic cells? a. mitochondrial matrix b. mitochondrial intermembrane space c. mitochondrial inner membrane d. mitochondrial outer membrane e. cytosol 8) The ATP made during glycolysis is generated by a. electron transport. b. oxidation of NADH to NAD+. c. substrate-level phosphorylation. d. photophosphorylation. e. chemiosmosis. 9) Why are carbohydrates and fats considered high energy foods? a. They can have very long carbon skeletons. b. They have a lot of oxygen atoms. c. They are easily reduced. d. They have no nitrogen in their makeup. e. They have a lot of electrons associated with hydrogen. 10) The primary role of oxygen in cellular respiration is to a. act as an acceptor for electrons and hydrogen, forming water. b. combine with carbon, forming CO2. c. yield energy in the form of ATP as it is passed down the respiratory chain. d. catalyze the reactions of glycolysis. e. combine with lactate, forming pyruvate. 11) Inside an active mitochondrion, most electrons follow which pathway? a. citric acid cycle → NADH→ electron transport chain → oxygen b. citric acid cycle → FADH2 → electron transport chain → ATP c. electron transport chain → citric acid cycle → ATP → oxygen d. glycolysis → NADH → oxidative phosphorylation → ATP → oxygen e. pyruvate → citric acid cycle → ATP → NADH → oxygen 12) Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells? a. mitochondrial intermembrane space b. cytosol c. mitochondrial inner membrane d. mitochondrial outer membrane e. mitochondrial matrix 13) Which of the following occurs in the cytosol of a eukaryotic cell? a. fermentation and chemiosmosis b. oxidation of pyruvate to acetyl CoA c. citric acid cycle d. oxidative phosphorylation e. glycolysis and fermentation 14) In chemiosmotic phosphorylation, what is the most direct source of energy that is used to convert ADP + Pi to ATP? a. Energy released from substrate-level phosphorylation b. No external source of energy is required because the reaction is exergonic. c. Energy released from ATP synthase pumping hydrogen ions from the mitochondrial matrix. d. Energy released from movement of protons through ATP synthase e. Energy from pyruvate 15) Which of the following sequences correctly represents the flow of electrons during photosynthesis? a. NADPH  Electron Transport Chain  O2 b. H2O  NADPH  Calvin Cycle c. NADPH  Chlorphyll  Calvin Cycle d. H2O  Photosystem I  Photosystem II e. NADPH  O2 CO2 16) If photosynthesizing green algae are provided with CO2 synthesized with heavy oxygen (18O), later analysis will show that all but one of the following compounds produced by the algae contain the 18O label. That one is a. 3-phosphoglycerate. b. O2. c. glyceraldehyde 3-phosphate (G3P). d. ribulose bisphosphate (RuBP). e. glucose. 17) Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle? a. ADP, i, and NADP+ b. Electrons and H+ c. ATP and NADPH d. H2O and O2 e. CO2 and glucose 18) In the thylakoid membranes, what is the main role of the antenna pigment molecules? a. transfer electrons to ferredoxin and then NADPH b. split water and release oxygen to the reaction-center chlorophyll c. concentrate photons within the stroma d. harvest photons and transfer light energy to the reaction-center chlorophyll e. synthesize ATP from ADP + i 19) When oxygen is released as a result of photosynthesis, it is a direct by -product of a. splitting water molecules. b. the electron transfer system of photosystem II. c. the electron transfer system of photosystem I. d. chemiosmosis. e. reducing NADP+. 20) P680+ is said to be the strongest biological oxidizing agent. Why? a. It transfers its electrons to reduce NADP+ to NADPH. b. This molecule has a stronger attraction for electrons than oxygen, to obtain electrons from water. c. It has a positive charge. d. It is the molecule that transfers electrons to Pq (plastoquinone) of the electron transfer system. e. It is the receptor for the most excited electron in either photosystem.