BIO 239

Which of the following is true of aerobic respiration compared to anaerobic respiration? Aerobic respiration uses oxygen as a final electron acceptor, whereas anaerobic respiration uses an inorganic molecule other than oxygen as the final electron acceptor.. Aerobic respiration uses oxygen as a final electron acceptor, whereas anaerobic respiration uses an organic molecule. Aerobic respiration and anaerobic respiration both require oxygen as a final electron acceptor. Aerobic respiration is less efficient than all forms of anaerobic respiration, producing less ATP and larger end-products.

Aerobic respiration uses oxygen as a final electron acceptor, whereas anaerobic respiration uses an inorganic molecule other than oxygen as the final electron acceptor.

In this activity, you will be asked to examine the illustration above and determine whether each of a series of statements correctly describes the process.

Correct statements: * The final electron acceptor is O2. *The pH of the intermembrane space in mitochondria would be lower than the pH of the mitochondrial matrix in an actively metabolizing cell. *A chemical that inactivates cytochrome c so that it can't pass electrons on to cytochrome a would block electron transport and ATP synthesis. *A toxin that causes a leak to form in the inner mitochondrial membrane such that protons could bypass the ATP synthase would prevent oxidative phosphorylation. Incorrect statements: *ATP serves as an electron carrier in the electron transport chain.*The electrons carried by FADH2 have more potential energy than those carried by NADH. *A toxin that causes a leak to form in the inner mitochondrial membrane such that protons could bypass the ATP synthase would disrupt the flow of electrons to O2. *Electrons moving from the FMN to Q to cytochrome b are gaining energy.

All organisms use oxidation-reduction reactions to harness energy, and this newly harvested energy is used to produce ATP. Oxidation is defined as the loss of electrons. Reduction is the gain of electrons. The energy in fuel molecules (often carbohydrates) is in the form of electrons. When electrons are removed from their high-energy state in fuel molecules (the electron donors), those molecules are oxidized. The electrons must be added to another molecule, which serves as the electron acceptor. As it gains electrons, the electron acceptor is reduced. When these electrons arrive at the final electron acceptor, they are at a lower-energy state compared to their original position in the electron donor. The goal is to harness the energy the electrons lose during this transfer process. In this activity, you will examine three equations and indicate which reactants are electron donors and which are receptors. In addition, you will identify the oxidized product and the reduced product. The image below shows three different oxidation-reduction equations. Sort each of the lettered items on the image into the proper bin.

Electron donors: a, i, e Electron acceptors: f, b, j Oxidized product: g, c, k Reduced product: d, l, h

What is the fate of pyruvic acid in an organism that uses aerobic respiration? It is catabolized in glycolysis. It is oxidized in the electron transport chain.It is reduced to lactic acid. It is converted into acetyl CoA. It reacts with oxaloacetate to form citrate.

It is converted into acetyl CoA.

Select all statements that correctly describe glycolysis. Pyruvate is the electron acceptor. This process occurs in the mitochondria of eukaryotic cells. CO2 is produced during glycolysis. Glyceraldehyde 3-phosphate is oxidized, and NAD+ is reduced to NADH. The 6-carbon skeleton of glucose is enzymatically split into two 3-carbon compounds. Glucose is the original electron donor.

More ATP is formed than is consumed in this process. Glyceraldehyde 3-phosphate is oxidized, and NAD+ is reduced to NADH.Glucose is the original electron donor. The 6-carbon skeleton of glucose is enzymatically split into two 3-carbon compounds.

Which of the following statements regarding the EntnerDoudoroff pathway is TRUE? It involves the pentose phosphate pathway. NADH is generated. NADH and ATP are generated. ATP is generated. It involves glycolysis.

NADH and ATP are generated.

From the list below, which is NOT produced during the Krebs cycle? ATP CO2 NADPH NADH FADH2

NADPH

Assume you are working for a chemical company and are responsible for growing a yeast culture that produces ethanol. The yeasts are growing well on the maltose medium but are not producing alcohol. What is the most likely explanation? The maltose is toxic. O2 is in the medium. The temperature is too low. The temperature is too high. Not enough protein is provided.

O2 is in the medium.

Which of the following statements regarding the glycolysis pathway is FALSE? Four ATP molecules are generated via substrate-level phosphorylation. Two molecules of water are generated. One molecule of ATP is expended. Two pyruvate molecules are generated. Two NADH molecules are generated.

One molecule of ATP is expended.

Compare and contrast three metabolic pathways by choosing whether the statement applies to aerobic respiration.

Process involves electron transport and chemiosmosis Process involves the Krebs cycle A total of 38 ATP are produced per molecule of glucose input. The coenzyme NAD+ plays an important role in the pathway. Much or most of the ATP produced is produced by oxidative phosphorylation. End products are CO2 and H2O Process includes glycolysis

Compare and contrast three metabolic pathways by choosing whether the statement applies to anaerobic respiration.

Process involves the Krebs cycle Process includes glycolysis Between 2 and 38 ATP are produced per molecule of glucose input. Much or most of the ATP produced is produced by oxidative phosphorylation. Can generate ATP in the absence of O2. The coenzyme NAD+ plays an important role in the pathway. Process involves electron transport and chemiosmosis

A key feature of cellular respiration is the removal of electrons from fuel molecules (oxidation) and the ultimate acceptance of these electrons by a low-energy electron acceptor. The process involves the use of electron carriers, NAD+ and FAD, which play crucial roles in multiple steps of the metabolic pathways. The overall equation for cell respiration is shown below. Why do NAD+ and FAD NOT appear in the overall equation? C6H12O6+6O2+38ADP+38Pi→6CO2+6H2O+38ATPC6H12O6+6O2+38ADP+38Pi→6CO2+6H2O+38ATP The NAD+ and FAD are initially reduced then oxidized to their original state, so they do not appear in the net equation. This pathway doesn't use electron carriers such as NAD+ and FAD and uses only the electron transport chain. Glucose and CO2 are the electron carriers in this pathway. ADP is the electron carrier in this pathway and picks up electrons to form ATP.

The NAD+ and FAD are initially reduced then oxidized to their original state, so they do not appear in the net equation.

Compare and contrast three metabolic pathways by choosing whether the statement applies to fermentation.

The coenzyme NAD+ plays an important role in the pathway. Can generate ATP in the absence of O2. End products may include lactic acid or ethanol. Process includes glycolysis A total of 2 ATP are produced per molecule of glucose input.

Select all statements that correctly describe the preparatory step and the Krebs cycle. The oxaloacetic acid that accepts the acetyl group is regenerated, enabling the cyclic nature of this process. It takes two "turns" of the Krebs cycle to process the pyruvic acid molecules resulting from the glycolysis of one glucose molecule. The potential energy in the pyruvate is transferred to coenzymes NAD+ and FAD. CO2 serves as the electron acceptor. There are five oxidation-reduction reactions depicted. The equivalent of one ATP is made for each turn of the Krebs cycle.Carbons from pyruvic acid end up as CO2. This process occurs in mitochondria in both eukaryotes and prokaryotes.

The equivalent of one ATP is made for each turn of the Krebs cycle. It takes two "turns" of the Krebs cycle to process the pyruvic acid molecules resulting from the glycolysis of one glucose molecule. The potential energy in the pyruvate is transferred to coenzymes NAD+ and FAD. Carbons from pyruvic acid end up as CO2. There are five oxidation-reduction reactions depicted. The oxaloacetic acid that accepts the acetyl group is regenerated, enabling the cyclic nature of this process.

The rates of O2 and glucose consumption by a bacterial culture are shown in the figure. Assume a bacterial culture was grown in a glucose medium without O2. Then O2 was added at the time marked X. The data indicate that these bacteria don't use O2. aerobic metabolism is more efficient than fermentation. these bacteria cannot grow anaerobically. these bacteria get more energy anaerobically.

aerobic metabolism is more efficient than fermentation.

A bacterium that only possesses the ability to ferment obtains energyby aerobic respiration only. by glycolysis only. by fermentation or aerobic respiration. only in the absence of oxygen.only in the presence of oxygen.

by glycolysis only.

Why do eukaryotes generate only about 36 ATP per glucose in aerobic respiration but prokaryotes may generate about 38 ATP? eukaryotes must shuttle pyruvate across the mitochondrial membrane by active transport. prokaryotes possess an alternate to the Krebs cycle that generates more reduced electron. carriers.eukaryotes have a less efficient electron transport system. eukaryotes do not completely oxidize glucose in their respiration reactions. eukaryotes do not transport as much hydrogen across the mitochondrial membrane as prokaryotes do across the cytoplasmic membrane.

eukaryotes must shuttle pyruvate across the mitochondrial membrane by active transport.

In cellular respiration of glucose, what are the three principal stages? Calvin-Benson cycle, electron transport chain, and glycolysis fermentation, Krebs cycle, and electron transport chainchemiosmosis, photophosphorylation, and reduction glycolysis, Krebs cycle, and the electron transport chain

glycolysis, Krebs cycle, and the electron transport chain

If a cell is starved for ATP, which of the following pathways would most likely be shut down? glycolysis Krebs cycleKrebs cycle and glycolysis pentose phosphate pathway

pentose phosphate pathway

Which of the following is the best definition of fermentation? the partial reduction of glucose to pyruvic acidthe production of energy by both substrate and oxidative phosphorylation the complete catabolism of glucose to CO2 and H2O the production of energy by oxidative-level phosphorylation the partial oxidation of glucose with organic molecules serving as electron acceptors

the partial oxidation of glucose with organic molecules serving as electron acceptors

A bacterium such as Pseudomonas uses nitrate as a final electron acceptor in an electron transport system. All the below statements are true EXCEPT the process does not yield as much ATP. the process requires an electron donor. they can respire without O2. the process produces nitrite ion.they require light.

they require light.