MBIO 3400: Exam 3 with verified
answers already passed
How does the concept of species differ between prokaryotes and eukaryotes? - correct answer ✔✔-
Prokaryotes: asexual
-Eukaryotes: sexual
What molecular technique is most widely used today to distinguish evolutionary lineages of
microorganisms? - correct answer ✔✔-Phylogenic Tree
-Sequencing of the small subunit RNA model and
making sequence comparisons between different prokaryotic organisms. Led to discovery of Archie
What are the three domain of life? - correct answer ✔✔-Eukaryotes
-Bacteria (Prokaryotic)
-Archae
What are stromatolites? - correct answer ✔✔-Mineralized malts
-Calcium carbonate which becomes mineralized
What distinguishes cyanobacteria from other photosynthetic prokaryotes in terms of their
photosynthetic metabolism? - correct answer ✔✔-Cyanobacteria: they can be unicellular or filamentous
-The filamentous species can grow in forms of Mats
-Mats serve as a home for the bacteria (based on photosynthesis of cyanobacteria)
How do some filamentous cyanobacteria carry out nitrogen fixation? - correct answer ✔✔-Key enzyme:
nitrogenase (extremely O2 sensitive)
-Heterocyst: source at the site where nitrogen fixation occurs and where nitrogenase is active
-Takes nitrogen gas out of the atmosphere and turns it into organic nitrogen
, What distinguishes purple and green photosynthetic bacteria from other photosynthetic prokaryotes in
terms of their photosynthetic metabolism? - correct answer ✔✔-Anoxygenic photosynthesis. Can't
produce oxygen gas. Cannot use water as a source of hydrogen instead they use other hydrogen rich
compounds in the environment. Typically grow under anaerobic conditions. Use hydrogen sulfide or
hydrogen gas (H2). Instead of chlorophyll A, these have modified versions of chlorophyll
(bacteriochlorophyll). Don't produce oxygen. Cyanobacteria and eukaryotic algae that have chlorophyll A
grow at the top.
What are bacteriochlorophylls? - correct answer ✔✔-Instead of chlorophyll A (pigment that
cyanobacteria have to absorb light for photosynthesis) these have modified versions of chlorophyll
(bacteriochlorophyll). Don't produce oxygen. Cyanobacteria and eukaryotic plants/algae that have
chlorophyll A grow at the top.
Where do photosynthetic microorganisms grow in stratified (meromictic) lakes? - correct answer ✔✔-
Typically the cyanobacteria and the eukaryotic algae grow in the uppermost layer of the lake. And the
purple and green bacteria grow deeper in the lake.
What are the unique metabolic aspects of nitrifying bacteria? What distinguishes the two different
groups of these bacteria? - correct answer ✔✔-Ammonium nitrite nitrate
-Ammonium is oxidized to nitrate in 2 steps by 2 separate groups of nitrifying bacteria that catalyze these
steps.
What is a unique characteristic of some spirilla as discussed in lecture? - correct answer ✔✔-Spiral
shaped bacteria.
-Some are able to sense the Earth's magnetic field.
-In low O2 areas (microaerophilic)
What unique characteristics do Hyphomicrobium and Caulobacter possess? - correct answer ✔✔-
Hyphomicrobium: a genus of rod-shaped, oval, or bean-shaped bacteria found in soil and fresh water.
Polar prosthecae are present and cells reproduce by budding at the tips of the prosthecae. Cells of this
genus are aerobic and grow best with one-carbon compounds.
-Caulobacter: A single-celled slightly curved bacterium that thrives in watery environments. It exists in
two forms: a flagellated swarmer cell, and stalked cell.
What is gliding motility? - correct answer ✔✔-Alternative to flagellant motility
answers already passed
How does the concept of species differ between prokaryotes and eukaryotes? - correct answer ✔✔-
Prokaryotes: asexual
-Eukaryotes: sexual
What molecular technique is most widely used today to distinguish evolutionary lineages of
microorganisms? - correct answer ✔✔-Phylogenic Tree
-Sequencing of the small subunit RNA model and
making sequence comparisons between different prokaryotic organisms. Led to discovery of Archie
What are the three domain of life? - correct answer ✔✔-Eukaryotes
-Bacteria (Prokaryotic)
-Archae
What are stromatolites? - correct answer ✔✔-Mineralized malts
-Calcium carbonate which becomes mineralized
What distinguishes cyanobacteria from other photosynthetic prokaryotes in terms of their
photosynthetic metabolism? - correct answer ✔✔-Cyanobacteria: they can be unicellular or filamentous
-The filamentous species can grow in forms of Mats
-Mats serve as a home for the bacteria (based on photosynthesis of cyanobacteria)
How do some filamentous cyanobacteria carry out nitrogen fixation? - correct answer ✔✔-Key enzyme:
nitrogenase (extremely O2 sensitive)
-Heterocyst: source at the site where nitrogen fixation occurs and where nitrogenase is active
-Takes nitrogen gas out of the atmosphere and turns it into organic nitrogen
, What distinguishes purple and green photosynthetic bacteria from other photosynthetic prokaryotes in
terms of their photosynthetic metabolism? - correct answer ✔✔-Anoxygenic photosynthesis. Can't
produce oxygen gas. Cannot use water as a source of hydrogen instead they use other hydrogen rich
compounds in the environment. Typically grow under anaerobic conditions. Use hydrogen sulfide or
hydrogen gas (H2). Instead of chlorophyll A, these have modified versions of chlorophyll
(bacteriochlorophyll). Don't produce oxygen. Cyanobacteria and eukaryotic algae that have chlorophyll A
grow at the top.
What are bacteriochlorophylls? - correct answer ✔✔-Instead of chlorophyll A (pigment that
cyanobacteria have to absorb light for photosynthesis) these have modified versions of chlorophyll
(bacteriochlorophyll). Don't produce oxygen. Cyanobacteria and eukaryotic plants/algae that have
chlorophyll A grow at the top.
Where do photosynthetic microorganisms grow in stratified (meromictic) lakes? - correct answer ✔✔-
Typically the cyanobacteria and the eukaryotic algae grow in the uppermost layer of the lake. And the
purple and green bacteria grow deeper in the lake.
What are the unique metabolic aspects of nitrifying bacteria? What distinguishes the two different
groups of these bacteria? - correct answer ✔✔-Ammonium nitrite nitrate
-Ammonium is oxidized to nitrate in 2 steps by 2 separate groups of nitrifying bacteria that catalyze these
steps.
What is a unique characteristic of some spirilla as discussed in lecture? - correct answer ✔✔-Spiral
shaped bacteria.
-Some are able to sense the Earth's magnetic field.
-In low O2 areas (microaerophilic)
What unique characteristics do Hyphomicrobium and Caulobacter possess? - correct answer ✔✔-
Hyphomicrobium: a genus of rod-shaped, oval, or bean-shaped bacteria found in soil and fresh water.
Polar prosthecae are present and cells reproduce by budding at the tips of the prosthecae. Cells of this
genus are aerobic and grow best with one-carbon compounds.
-Caulobacter: A single-celled slightly curved bacterium that thrives in watery environments. It exists in
two forms: a flagellated swarmer cell, and stalked cell.
What is gliding motility? - correct answer ✔✔-Alternative to flagellant motility
