MICR 271 Test 1 Questions with Correct Answers
What are the three interconnected Domains of Life
Bacteria, Archaea, and Eukaryota
Which of these are prokaryotes
Bacteria and Archaea
What describes the evolutionary connections between prokaryotes (Bacteria and
Archaea) and eukaryotes (Eukaryota, which includes all organisms with nucleated cells)
endosymbiont theory
Describe endosymbiont theory
eukaryotes evolved more complex structures and metabolic processes by building upon
prokaryotic attributes.
define microbe
microscopic living organism that may be single-celled or multicellular. While some
eukaryotes are microbes, others are complex multicellular organisms such as animals and
plants
what are cyanobacteria
photosynthetic bacteria that produce O2
Which is more complex, prokaryotes or eukaryotes?
Eukaryotic organisms have evolved more complex structures than prokaryotes.
How would you summarize the differences between prokaryotes or eukaryotes in one
phrase?
,Eukaryotes have membrane-bound organelles and prokaryotes do not.
define Eukaryota
An organism whose cells contain a nucleus and other organelles enclosed in membranes
define Archaea
Domain of single-celled prokaryotic microorganisms which do not have peptidoglycan in
their cell walls
define Bacteria
Domain of single-celled prokaryotic microorganisms characterized by peptidoglycan
containing cell walls
Revisit: what's the The endosymbiont hypothesis
primary hypothesis regarding the evolution of eukaryotes from prokaryotes
what is it based on?
based on the similarities found between bacteria and mitochondria
How did mitochondria and chloroplasts evolve from free-living bacteria
symbiosis
define Symbiosis
The living together or close association of two dissimilar organisms, each of these organisms
being known as a symbiont.
What key differences did they develop through symbiosis evolution?
these organelles contain their own DNA (separate genome) and a distinct translation system.
, what is an α-proteobacteria member?
the ancestor of mitochondria, however there is little agreement as to which member
What are the two theories of mitochondrial symbiosis
1. Archezoan Scenario
2. Symbiogenesis Scenario
What is the major difference between these theories?
whether the incorporation of the proto-mitochondrion was a critical step in the formation of a
eukaryotic cell, or if it happened after the formation of an essentially eukaryotic cell
what does the archezoan scenario hypothesize
a primitive mitochondrial eukaryote cell phagocytosed an α-proteobacterium. This
phagocytosis subsequently led to the evolution of the mitochondrion.
(cell developed the mitochondria)
Is this theory still favored?
No
Why has the theory fallen out of favor?
The original phylogenetic analysis mistakenly placed branches of some eukaryotic protists
close to the 'base' of the Tree of Life.
What did the mistaken phylogenetic analysis suggest?
It suggested early incorporation of proto-mitochondria.
define Proto-mitochondria
What are the three interconnected Domains of Life
Bacteria, Archaea, and Eukaryota
Which of these are prokaryotes
Bacteria and Archaea
What describes the evolutionary connections between prokaryotes (Bacteria and
Archaea) and eukaryotes (Eukaryota, which includes all organisms with nucleated cells)
endosymbiont theory
Describe endosymbiont theory
eukaryotes evolved more complex structures and metabolic processes by building upon
prokaryotic attributes.
define microbe
microscopic living organism that may be single-celled or multicellular. While some
eukaryotes are microbes, others are complex multicellular organisms such as animals and
plants
what are cyanobacteria
photosynthetic bacteria that produce O2
Which is more complex, prokaryotes or eukaryotes?
Eukaryotic organisms have evolved more complex structures than prokaryotes.
How would you summarize the differences between prokaryotes or eukaryotes in one
phrase?
,Eukaryotes have membrane-bound organelles and prokaryotes do not.
define Eukaryota
An organism whose cells contain a nucleus and other organelles enclosed in membranes
define Archaea
Domain of single-celled prokaryotic microorganisms which do not have peptidoglycan in
their cell walls
define Bacteria
Domain of single-celled prokaryotic microorganisms characterized by peptidoglycan
containing cell walls
Revisit: what's the The endosymbiont hypothesis
primary hypothesis regarding the evolution of eukaryotes from prokaryotes
what is it based on?
based on the similarities found between bacteria and mitochondria
How did mitochondria and chloroplasts evolve from free-living bacteria
symbiosis
define Symbiosis
The living together or close association of two dissimilar organisms, each of these organisms
being known as a symbiont.
What key differences did they develop through symbiosis evolution?
these organelles contain their own DNA (separate genome) and a distinct translation system.
, what is an α-proteobacteria member?
the ancestor of mitochondria, however there is little agreement as to which member
What are the two theories of mitochondrial symbiosis
1. Archezoan Scenario
2. Symbiogenesis Scenario
What is the major difference between these theories?
whether the incorporation of the proto-mitochondrion was a critical step in the formation of a
eukaryotic cell, or if it happened after the formation of an essentially eukaryotic cell
what does the archezoan scenario hypothesize
a primitive mitochondrial eukaryote cell phagocytosed an α-proteobacterium. This
phagocytosis subsequently led to the evolution of the mitochondrion.
(cell developed the mitochondria)
Is this theory still favored?
No
Why has the theory fallen out of favor?
The original phylogenetic analysis mistakenly placed branches of some eukaryotic protists
close to the 'base' of the Tree of Life.
What did the mistaken phylogenetic analysis suggest?
It suggested early incorporation of proto-mitochondria.
define Proto-mitochondria
