Chapter 5
How is ATP generated in the reaction shown in Figure 5.4?
substrate-level phosphorylation
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?
O2 is in the medium.
In green and purple bacteria, electrons to reduce CO2 can come from
H2S.
The use of enzymes is necessary to increase the activation energy requirements of a chemical reaction.
False
Which biochemical process is NOT used during glycolysis?
beta oxidation
Which of the following statements regarding the glycolysis pathway is FALSE?
One molecule of ATP is expended.
What is the fate of pyruvic acid in an organism that uses aerobic respiration?
It is converted into acetyl CoA.
An enzyme, citrate synthase, in the Krebs cycle is inhibited by ATP. This is an example of all of the following EXCEPT
competitive inhibition.
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.
2, 4, 5
Microorganisms that catabolize sugars into ethanol and hydrogen gas would most likely be categorized as
heterolactic fermenters
The pentose phosphate pathway can be characterized as an anabolic pathway.
False
From the list below, which is NOT produced during the Krebs cycle?
NADPH
A bacterial culture grown in a glucose-peptide medium causes the pH to increase. The bacteria are most likely
Using the peptides
Assume you are growing bacteria on a lipid medium that started at pH 7. The action of bacterial lipases should cause the pH of the medium to
decrease (become more acidic).
Which of the following uses glucose for carbon and energy?
chemoheterotroph
Gallionella bacteria can get energy from the reaction Fe2+ → Fe3+. This reaction is an example of
oxidation
In Figure 5.8, the structure labeled "1" is
a plasma membrane
Carbon fixation occurs during the light-independent phase of photosynthesis.
True
Which statements correspond to amphibolic pathways?
1.Anabolic
and catabolic reactions are joined through common intermediate.
2.They are shared metabolic pathways.
3.Feedback inhibition can help regulate rates of reactions.
4.Both types of reactions are necessary but do not occur simultaneously.
1,2,3
How would a noncompetitive inhibitor interfere with a reaction involving the enzyme shown in Figure 5.3?
It would bind to b.
Glycolysis is utilized by cells in both respiration and fermentation.
True
Which of the following compounds is NOT an enzyme?
coenzyme A
Which of the following has bacteriochlorophylls and uses alcohols for carbon?
photoheterotroph
Which of the following uses CO2 for carbon and H2 for energy?
chemoautotroph
In Figure 5.8, the path labeled "2" is the flow of
protons
Researchers are developing a ribozyme that cleaves the HIV genome. This pharmaceutical agent could be described as
an RNA molecule capable of catalysis.
Which organism is NOT correctly matched to its energy source?
photoautotroph - CO2 chemoautotroph - NH3
In general, ATP is generated in catabolic pathways and expended in anabolic pathways.
True
Refer to Figure 5.8. In aerobic respiration, where is water formed?
d
If a cell is starved for ATP, which of the following pathways would most likely be shut down?
pentose phosphate pathway
Which of the following is the best definition of fermentation?
the partial oxidation of glucose with organic molecules serving as electron acceptors
In non-cyclic photophosphorylation, excited electrons ultimately
combine with hydrogen ions and NADP+ to produce NADPH.
Which of the graphs in Figure 5.5 best illustrates the activity of an enzyme that is saturated with substrate?
c
A bacterium such as Pseudomonas uses nitrate as a final electron acceptor in an electron transport system. All the below statements are true EXCEPT
they require light.
Both respiration and photosynthesis require the use of an electron transport chain.
True