MIC 205A Exam 2 2025 Questions and
Answers
Streptococcus pneumoniae lacks an electron transport chain. Therefore, S. pneumoniae
generates ATP only via _______________. - ANS glycolysis
Removing the electron transport chain of E. coli would - ANS prevent oxidative
phosphorylation.
You inoculate fern spores onto the surface of a growth medium in Petri dishes and wait for
them to develop into gametophytes, a stage in the life cycle of a fern. The medium contains
sources of nitrogen, phosphate, and a number of other macro- and micro-nutrients, but no
carbon. After a few weeks, you see a contaminant growing on your plates. Assuming the
organism is not digesting the agar itself, which of the following is most likely your contaminant?
- ANS Photoautotrophic species of bacteria, archaea, or protists.
Consider common human pathogens. Most of their enzymes likely function best under which of
the following environmental conditions? (You may select more than one answer. Single click
the box with the question mark to produce a check mark for a correct answer and double click
the box with the question mark to empty the box for a wrong answer. Any boxes left with a
question mark will be automatically graded as incorrect.) - ANS Temperature around 37
degrees C, Low salt, Moderate pH around 7
The three central metabolic pathways—glycolysis, the pentose phosphate pathway, and the
tricarboxylic acid cycle (TCA cycle)—modify organic molecules to generate what three useful
components for the cell? - ANS ATP, Reducing power, Precursor metabolites
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,A population of bacteria is breaking down some lipids to support microbial growth. Where do
the products of lipid breakdown enter the central metabolic pathway? - ANS Glycolysis, TCA
cycle
Some enzymes require a cofactor or a coeznyme in order to be active. What is the difference
between cofactors and coenzymes? - ANS Cofactors are non-protein components that assist
enzymes and are typically trace elements; coenzymes are organic cofactors that loosely carry
molecules or electrons.
Greenlake is a small lake in Seattle, WA that sometimes experiences blooms of cyanobacteria,
photosynthetic nitrogen-fixing bacteria that typically grow as filaments. These blooms are
especially likely to occur during warm summer weather and result in the production of large
quantities of biomass that then dies off and decomposes, leading to unpleasant odors. In
addition to the aesthetic problems, some strains make toxins that can be dangerous to ingest,
leading to the closing of the lake. Treatment of the water with alum (aluminum sulfate) to
remove phosphorus from the water has helped to limit growth of cyanobacteria.
How would you classify the cyanobacteria from Greenlake in terms of their carbon and energy
sources? - ANS Photoautotroph
Scientists isolated a new species of bacteria growing in sediments collected from a 63 meter
deep site at the bottom of Lake Washington in Seattle This species, named Labrys
methylaminiphilus, is capable of obtaining its carbon and energy needs from methylamine
(CH3NH2), a derivative of ammonia (NH3) in which one H atom is replaced by a methyl (CH3)
group. L. methylaminiphilus grows at a temperature range of 10-35°C, with optimal growth at
28-30°C, and a pH range of 4.0-9.5, with optimal growth at 5.0-7.0. Because methylamine is a
single carbon compound resulting from the breakdown of decaying organic matter,
methylotrophic ("methyl-feeding") bacteria like L. methylaminiphilus play an important role in
carbon cycling in lake sediments and other environments.
Consider the growth of L. methylaminiphilus on methylamine. How would you classify this
species based on its metabolism? - ANS Chemoorganoheterotroph
Pg. 2 Copyright © 2025 Jasonmcconell. ALL RIGHTS RESERVED.
, Which of the following compounds can be generated from precursor metabolites in the TCA
cycle? - ANS Some amino acids like aspartate, glutamate, and proline, Certain protein
components.
You are studying the metabolism of the phototrophic green sulfur bacterium Chlorobaculum
tepidum and realize that it is running a reversed TCA cycle! How do you explain this
observation? - ANS C. tepidum is using the reversed TCA cycle to fix carbon dioxide.
n prokaryotic cells, the electron transport chain (ETC) is located in the ______, whereas in
eukaryotic cells, the ETC is located in the ______. - ANS cytoplasmic membrane; inner
membrane of mitochondria
How do chemolithotrophs acquire energy? - ANS From inorganic compounds
Which of the following are enzymes involved in anabolic reactions? - ANS ATP synthase -
generates ATP
DNA polymerase- generates DNA
DNA ligase - joins DNA fragments together
RNA polymerase - generates RNA
The terminal electron acceptor in aerobic respiration is ______. - ANS oxygen
Glycolysis is the central metabolic pathway that involves the breakdown of ______. -
ANS glucose
3. The energy released during the reactions of glycolysis is used to form ______. -
ANS adenosine triphosphate
Cells prefer to use carbohydrates as energy sources because - ANS they are such good
donors of hydrogen and electrons.
Pg. 3 Copyright © 2025 Jasonmcconell. ALL RIGHTS RESERVED.
Answers
Streptococcus pneumoniae lacks an electron transport chain. Therefore, S. pneumoniae
generates ATP only via _______________. - ANS glycolysis
Removing the electron transport chain of E. coli would - ANS prevent oxidative
phosphorylation.
You inoculate fern spores onto the surface of a growth medium in Petri dishes and wait for
them to develop into gametophytes, a stage in the life cycle of a fern. The medium contains
sources of nitrogen, phosphate, and a number of other macro- and micro-nutrients, but no
carbon. After a few weeks, you see a contaminant growing on your plates. Assuming the
organism is not digesting the agar itself, which of the following is most likely your contaminant?
- ANS Photoautotrophic species of bacteria, archaea, or protists.
Consider common human pathogens. Most of their enzymes likely function best under which of
the following environmental conditions? (You may select more than one answer. Single click
the box with the question mark to produce a check mark for a correct answer and double click
the box with the question mark to empty the box for a wrong answer. Any boxes left with a
question mark will be automatically graded as incorrect.) - ANS Temperature around 37
degrees C, Low salt, Moderate pH around 7
The three central metabolic pathways—glycolysis, the pentose phosphate pathway, and the
tricarboxylic acid cycle (TCA cycle)—modify organic molecules to generate what three useful
components for the cell? - ANS ATP, Reducing power, Precursor metabolites
Pg. 1 Copyright © 2025 Jasonmcconell. ALL RIGHTS RESERVED.
,A population of bacteria is breaking down some lipids to support microbial growth. Where do
the products of lipid breakdown enter the central metabolic pathway? - ANS Glycolysis, TCA
cycle
Some enzymes require a cofactor or a coeznyme in order to be active. What is the difference
between cofactors and coenzymes? - ANS Cofactors are non-protein components that assist
enzymes and are typically trace elements; coenzymes are organic cofactors that loosely carry
molecules or electrons.
Greenlake is a small lake in Seattle, WA that sometimes experiences blooms of cyanobacteria,
photosynthetic nitrogen-fixing bacteria that typically grow as filaments. These blooms are
especially likely to occur during warm summer weather and result in the production of large
quantities of biomass that then dies off and decomposes, leading to unpleasant odors. In
addition to the aesthetic problems, some strains make toxins that can be dangerous to ingest,
leading to the closing of the lake. Treatment of the water with alum (aluminum sulfate) to
remove phosphorus from the water has helped to limit growth of cyanobacteria.
How would you classify the cyanobacteria from Greenlake in terms of their carbon and energy
sources? - ANS Photoautotroph
Scientists isolated a new species of bacteria growing in sediments collected from a 63 meter
deep site at the bottom of Lake Washington in Seattle This species, named Labrys
methylaminiphilus, is capable of obtaining its carbon and energy needs from methylamine
(CH3NH2), a derivative of ammonia (NH3) in which one H atom is replaced by a methyl (CH3)
group. L. methylaminiphilus grows at a temperature range of 10-35°C, with optimal growth at
28-30°C, and a pH range of 4.0-9.5, with optimal growth at 5.0-7.0. Because methylamine is a
single carbon compound resulting from the breakdown of decaying organic matter,
methylotrophic ("methyl-feeding") bacteria like L. methylaminiphilus play an important role in
carbon cycling in lake sediments and other environments.
Consider the growth of L. methylaminiphilus on methylamine. How would you classify this
species based on its metabolism? - ANS Chemoorganoheterotroph
Pg. 2 Copyright © 2025 Jasonmcconell. ALL RIGHTS RESERVED.
, Which of the following compounds can be generated from precursor metabolites in the TCA
cycle? - ANS Some amino acids like aspartate, glutamate, and proline, Certain protein
components.
You are studying the metabolism of the phototrophic green sulfur bacterium Chlorobaculum
tepidum and realize that it is running a reversed TCA cycle! How do you explain this
observation? - ANS C. tepidum is using the reversed TCA cycle to fix carbon dioxide.
n prokaryotic cells, the electron transport chain (ETC) is located in the ______, whereas in
eukaryotic cells, the ETC is located in the ______. - ANS cytoplasmic membrane; inner
membrane of mitochondria
How do chemolithotrophs acquire energy? - ANS From inorganic compounds
Which of the following are enzymes involved in anabolic reactions? - ANS ATP synthase -
generates ATP
DNA polymerase- generates DNA
DNA ligase - joins DNA fragments together
RNA polymerase - generates RNA
The terminal electron acceptor in aerobic respiration is ______. - ANS oxygen
Glycolysis is the central metabolic pathway that involves the breakdown of ______. -
ANS glucose
3. The energy released during the reactions of glycolysis is used to form ______. -
ANS adenosine triphosphate
Cells prefer to use carbohydrates as energy sources because - ANS they are such good
donors of hydrogen and electrons.
Pg. 3 Copyright © 2025 Jasonmcconell. ALL RIGHTS RESERVED.
