Microbio

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.

Consider the glycolysis pathway. Select all statements that correctly describe glycolysis.

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.More ATP is formed than is consumed in this process.

What is the fate of pyruvic acid in an organism that uses aerobic respiration?

It is converted into acetyl CoA.

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+38ATP

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

When bacteria are inoculated into a new sterile nutrient broth, their numbers don't begin to increase immediately. Instead, there is a lag phase that may last for an hour or even several days. Why don't bacterial numbers increase immediately?

The bacteria must adjust to the nutrient content in the new medium, synthesizing necessary amino acids, growth factors, and enzymes

After a period of rapid growth (log phase), bacterial growth rates will slow and enter the stationary phase. The number of viable cells no longer increases, but instead stays constant. In this activity you will indicate the statements that correctly describe what is happening during stationary phase.

The cells are likely running out of nutrients. Harmful waste products may be accumulating. The number of cells that are dying is balanced by the number of new cells that are being formed.

Examine the figure above depicting the preparatory step and the Krebs cycle, and identify statements that correctly describe these processes. 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. There are five oxidation-reduction reactions depicted. Carbons from pyruvic acid end up as CO2. 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. The equivalent of one ATP is made for each turn of the Krebs cycle.

Microbes are often identified using biochemical tests that detect specific enzymes of metabolic pathways. E. coli typically ferments lactose, whereas Shigella does not. If a pure culture of each bacterium was placed in a tube containing lactose as the only food source, and a chemical indicator changed color after a pH change, what would the tubes look like after the bacteria were incubated?

The tube with E. coli would show a pH change, and the Shigella tube would show no change.

Which of the following terms refers to pathways that can function both in anabolism and catabolism?

amphibolic pathways

In cellular respiration of glucose, what are the three principal stages?

glycolysis, Krebs cycle, and the electron transport chain

A bacterial culture grown in a glucose-peptide medium causes the pH to increase. The bacteria are most likely

using the peptides.