Microbiology Exam #2
acetate, succinate, and glucose.
For a carbon source, chemoorganotrophs generally use compounds such as
Water
what does oxygen get reduced to at the end of the electron transport chain?
The concentration of protons is higher outside the membrane than inside.
what does the electron transport chain do to the concentration of hydrogen ions (protons)?
Carbon
A chemoorganotroph and a chemolithotroph in the same environment would NOT compete for
a redox reaction
A reaction that involves the transfer of electrons from one molecule to another is referred to as
NADH and FADH2
According to the animation, which compounds provide electrons to the system?
log or stationary growth phase.
By controlling the concentration of nutrients added into a chemostat continuously, cells can constantly be maintained at
late log to early stationary phase
During a growth curve of Aliivibrio fischeri, when would you expect to see the strongest bioluminescence?
the donor molecule loses an electron and becomes oxidized.
During an oxidation reaction,
OH- accumulates on the inside of the membrane while H+ accumulates on the outside.
During electron transport reactions,
Glucose
Glycolysis is an extremely important and ancient metabolic process. The term is generally used to refer to the Embden-Meyerhof-Parnas pathway, but other processes can also be used that start with the same substrate and that produce ATP (e.g., the Entner-Douderoff pathway). What is the substrate that is used for the first step classic process?
Protons move from outside the membrane to inside the membrane.
How does the proton gradient help ATP synthase to make ATP?
Translocation of three to four protons drives the F0 component of ATPase which in turn phosphorylates one ADP into ATP.
How does the proton motive force lead to production of ATP?
The terminal electron acceptor in anaerobic respiration is not oxygen
How is anaerobic respiration different from aerobic respiration?
True
If a substance is reduced, it gains electrons T/F
The available NAD+ would be converted to NADH and glycolysis would stop due to the lack of NAD+.
If an organism used glycolysis (Embden-Meyerhof-Parnas pathway) but were unable to use fermentation or an electron transport chain, what problem would develop?
exergonic and energy will be released
If ΔG0' is negative, the reaction is
increase the concentration of nutrients in the medium
In a culture grown in a chemostat (continuous culture), the best way to increase the yield of bacteria (numbers of cells per mL) would be to __________.
True
In electron transport systems, the electron carriers are membrane associated. T/F
Lack of iron would mean lack of heme, and thus lower amounts of functioning cytochrome proteins. This would mean lower energy yields.
Iron is considered an essential element for many bacteria. Based on the animation, how would lack of iron affect energy production of a bacterium?
Endospores.
Small acid-soluble proteins (SASPs) protect DNA from ultraviolet light and are found in high numbers within
Respiration with oxygen as a terminal electron acceptor generates more energy than respiration with other terminal electron acceptors.
Some organisms are capable of using aerobic respiration or anaerobic respiration but use aerobic respiration preferentially. Why do they use aerobic respiration when possible?
Glycolysis
The Embden-Meyerhof-Parnas pathway is another name for
most probable number method
The best choice for estimating the viable cell number of a water sample would be the __________.
whether there will be a requirement or production of energy
The change in Gibbs free energy for a particular reaction is MOST useful in determining
True
The net result of electron transport is the generation of a pH gradient and an electrochemical potential across the membrane. T/F
chemiosmosis.
The process of generating ATP using a proton gradient is referred to as
the difference in charge across the plasma membrane with protons outside the membrane and electrons inside the membrane
The proton motive force (PMF) is driven by __________.
the greater the change in free energy (ΔG0′), and the greater the energy released
The reduction potential (E0′) of a substance reflects its tendency to donate or accept electrons. The larger the difference (ΔE0′) between the reduction potentials of the electron donor and the electron acceptor, __________.
An organism uses an electron transport chain with sulfur as the terminal electron acceptor.
The term "anaerobic respiration" is often used more broadly than is strictly accurate. Which of the examples below is the best example of anaerobic respiration?
The reaction will be exergonic.
To calculate the free energy (ΔG0′) of a reaction, you can subtract the free energies of formation (Gf0) of the reactants from those of the products. Given the following data, what will be true of this reaction? C6H12O6 + O2→ CO2 + H2O Gf0 : -917.3 0 -394.4 -237.2
two molecules of pyruvate, two molecules of ATP, and two molecules of NADH
What are the net products of glycolysis (the Embden-Meyerhof-Parnas pathway)?
Ubiquinones are not made of protein; cytochromes are.
What is one difference between ubiquinones and cytochromes?
They are oxidized completely to carbon dioxide and water.
What is the fate of metabolites during respiration?
An energy carrier
What is the function of GTP?
Decarboxylation of pyruvic acid
What occurs at the bridge step?
when bacterial growth ceases due to limitation of an essential nutrient
When does endospore formation commence?
Along the plasma membrane
Where would you expect to find electron transport chains in a prokaryote?
Ferric iron, fumarate, and protons
Which compounds can serve as electron acceptors in anaerobic respiration?
Electron acceptor
Which feature of anaerobic and aerobic respiration is different between the two catabolic strategies?
α-ketoglutarate, oxaloacetate, and succinyl-CoA
Which intermediate compound(s) in the citric acid cycle is/are often used for biosynthetic pathways as well as carbon catabolism?
Molecular Oxygen
Which of the following can be used as a final electron acceptor for aerobic respiration?
Redox reactions involve an oxidation reaction coupled with a reduction reaction.
Which of the following statements regarding redox reactions is true?
FADH2 electrons enter the electron transport chain at a lower energy level.
Why does FADH2 yield less ATP than NADH?
The electron acceptor's net charge decreases.
Why is reduction the term used to describe the gain of an electron?
to generate NADPH
Why would some organisms need a metabolic pathway similar to glycolysis, such as the Entner-Doudoroff pathway?
Four
how many electron carriers are reduced in the Krebs cycle only?