Chapter 5: Mastering Biology and Chemistry

Why is ATP required for glycolysis? A) ATP makes it easier to break apart glucose into two three-carbon molecules. B) ATP is used to reduce NAD+ to NADH. C) ATP is used to convert DHAP into G3P. D) ATP is used to convert PEP into pyruvic acid.

Glycolysis literally means A) sugar splitting. B) Embden-Meyerhof. C) energy producing. D) sugar producing.

How many net ATPs can be made from one molecule of glucose in glycolysis? A) Six B) One C) Two D) Four

What carbon molecules remain at the end of glycolysis? A) Glucose B) Glyceraldehyde 3-phosphate (G3P) C) Pyruvic acid D) Dihydroxyacetone phosphate (DHAP)

Which of the following statements about glycolysis is true? A) All cells perform glycolysis. B) Glycolysis produces glucose. C) Glycolysis is the main source of NADH in the cell. D) Glycolysis is also called the Embden-Meyerhof pathway.

Glycolysis produces energy in which form? A) ATP B) NADH and ATP C) NADH D) NADH, ATP, and pyretic acid E) Pyruvic acid

What is meant by substrate-level phosphorylation? A) Production of ATP using energy from a proton gradient B) Production of ATP by transferring phosphates directly from metabolic products to ADP C) Splitting of glucose into two pyruvic acid molecules D) Reduction of NAD+ to NADH

What is the net production of ATP in glycolysis? A) Four ATP B) Six ATP C) Eight ATP D) Two ATP

What occurs at the bridge step of the Krebs cycle? A) The formation of oxaloacetate B) Decarboxylation of pyruvic acid C) The formation of succinyl CoA D) The production of GTP

How many electron carriers are reduced in the Krebs cycle only? A) Six B) Four C) Three D) Five

What is the function of GTP? A) An energy carrier B) An electron carrier C) A scaffolding for carbon atoms D) An oxidizer to produce CO2

What is the fate of metabolites during respiration? A) They are oxidized completely to carbon dioxide and water. B) They are oxidized completely to form pyruvic acid. C) They are reduced to from NADH and FADH2. D) They are rearranged to form GTP.

Which of the following is needed as a reactant for the first step of the citric acid cycle? A) Succinyl CoA B) Malic acid C) Citric acid D) Oxaloacetic acid

Where does the energy come from to power the formation of GTP? A) ATP B) Succinyl CoA C) NADH D) Water

How many molecules of ATP can be generated from one molecule of NADH? A) Two B) One C) Four D) Three

Where would you expect to find electron transport chains in a prokaryote? A) Along the outer mitochondrial membrane B) Along the cell wall C) Free-floating in the cytoplasm D) Along the inner mitochondrial membrane E) Along the plasma membrane

Which compounds provide electrons to the system? A) FADH2 B) NADH C) Water D) Oxygen E) NADH and FADH2

What does oxygen get reduced to at the end of the electron transport chain? A) Protons B) NADH C) Electrons D) ATP E) Water

What does the electron transport chain do to the concentration of hydrogen ions (protons)? A) The concentration of protons is higher outside the membrane than inside. B) The concentration of protons is lower outside the membrane than inside. C) The concentration of protons inside the membrane is equal to the concentration outside of the membrane

The process of generating ATP using a proton gradient is referred to as A) the electron transport chain. B) chemiosmosis. C) water damming.

Why does FADH2 yield less ATP than NADH? A) FADH2 binds directly to the ATP synthase enzyme. B) Electrons from FADH2 cannot pump hydrogen ions out of the cell. C) FADH2 electrons ultimately do not go to oxygen. D) FADH2 electrons enter the electron transport chain at a lower energy level.

Which of the following can be used as a final electron acceptor for aerobic respiration? A) Carbonate ion B) Sulfate ion C) Nitrate ion, sulfate ion and carbonate ion can all be used as a final electron acceptor. D) Molecular oxygen E) Nitrate ion

How does the proton gradient help ATP synthase to make ATP? A) Protons are not involved with this step; only electrons are. B) Protons move from inside the membrane to outside the membrane. C) Protons move from outside the membrane to inside the membrane. D) Protons move along the membrane.

Iron is considered an essential element for many bacteria. How would lack of iron affect energy production of a bacterium? A) Lack of iron would mean that most of the oxygen could be reduced to form water, improving energy yields. B) Lack of iron would not have any affect on this system. C) Lack of iron would mean lack of heme, and thus lower amounts of functioning cytochrome proteins. This would mean lower energy yields.

Why does lack of oxygen result in the halt of ATP synthesis? A) Oxygen prevents uncoupling of the electron transport chain. B) It causes one of the cytochromes in the electron transport chain to be permanently stuck in the reduced state. C) The chain shuts down and can no longer pump hydrogen ions across the membrane, and the proton gradient cannot be maintained.

Why might some cells uncouple the electron transport chain? A) Too much ATP is bad for the cell. B) Cells can use the energy from the proton gradient for functions other than producing ATP, such as heat generation. C) Uncoupling proteins offset the effect of cyanide. D) A cell does not require ATP

How does cyanide poisoning result in the decrease of ATP production? A) Cyanide permanently binds to oxygen, preventing its use as the final electron acceptor. B) Cyanide permanently oxidizes cytochrome a3, preventing other components to change into the reduced state. This causes the proton gradient to break down, stopping ATP synthesis. C) Cyanide permanently reduces cytochrome a3, preventing other components to change into the oxidized state. This causes the proton gradient to break down, stopping ATP synthesis. D) Cyanide uncouples the proton gradient from the process of ATP synthesis.

Which of the following situations does not result in a breakdown of the proton gradient? A) Oxygen deprivation B) Uncoupling proteins C) Cyanide poisoning

Which of the following statements about fermentation is true? A) It is an alternative way to return electron carriers to their oxidized state. B) It allows the electron transport chain to continue in the absence of oxygen. C) It provides additional protons to allow the electron transport chain to continue. D) It is an alternative way for a cell to produce oxygen.

What is the role of pyruvic acid in fermentation? A) It becomes the final electron acceptor for the electron transport chain in the absence of oxygen. B) It takes the electrons from NADH, oxidizing it back into NAD+. C) It is the organic acid end-product of fermentation. D) It provides the protons to be used in the electron transport chain.

What is the fate of the NAD+ newly regenerated by fermentation? A) It is oxidized into carbon dioxide. B) It is converted into an organic acid. C) It returns to glycolysis to pick up more electrons. D) It is converted into ethanol.

Which of the following is an acid produced by fermentation? A) Lactic acid and propionic acid B) Pyruvic acid C) Lactic acid D) Ethanol E) Propionic acid

What is the intermediate product formed by pyruvic acid during alcoholic fermentation? A) Ethanol B) Acetaldehyde C) Formic acid D) Carbon dioxide E) Lactic acid

(T/F) In general, ATP is generated in catabolic pathways and expended in anabolic pathways

Which of the following is true of anabolic reactions? A) Anabolic reactions produce energy, which is used to convert ADP to ATP. B) Anabolic reactions break down complex organic compounds into simpler ones. C) Anabolic and catabolic reactions both build complex organic molecules from simpler ones; however, anabolic reactions use ATP, whereas catabolic reactions transfer energy to create ATP. D) Anabolic reactions use ATP and small substrates as building blocks to synthesize larger molecules.

Which of the following statements are TRUE? 1-Electron carriers are located at ribosomes. 2-ATP is a common intermediate between catabolic and anabolic pathways. 3-ATP is used for the long-term storage of energy and so is often found in storage granules. 4-Anaerobic organisms are capable of generating ATP via respiration. 5-ATP can be generated by the flow of protons across protein channels.

(T/F) Once an enzyme has converted substrates into products, the active site reverts back to its original form.

(T/F) An apoenzyme that loses its coenzyme subunit will be non-functional.

Which of the following compounds is NOT an enzyme? A) cellulase B) dehydrogenase C) β-galactosidase D) sucrase E) coenzyme A

(T/F) Glycolysis is utilized by cells in both respiration and fermentation.

Which of the following statements regarding the Entner-Doudoroff pathway is TRUE? A) NADH is generated. B) NADH and ATP are generated. C) ATP is generated. D) It involves glycolysis. E) It involves the pentose phosphate pathway

Which of the following is NOT necessary for respiration? A) flavoproteins B) oxygen C) cytochromes D) quinones E) a source of electrons

Which biochemical process is NOT used during glycolysis? A) beta oxidation B) carbohydrate catabolism substrate-level C) phosphorylation D) oxidation-reduction E) enzymatic reactions

(T/F) Both respiration and photosynthesis require the use of an electron transport chain.

Which of the following uses glucose for carbon and energy? A) chemoautotroph B) chemoheterotroph C) photoautotroph D) photoheterotroph