MICR 271 Midterm Questions With Complete Solutions
_____________ is abundant in the atmosphere but only a few
species of microbes can use it in this form Correct Answers
Nitrogen
2 main types of bacteria in human microbiome Correct Answers
1)Pathogenic Bacteria
2)Commensal Bacteria
2 mechanisms of mutations Correct Answers 1)Spontaneous
mutations
2)Induced via external agents
3 Domains Correct Answers 1)Archaea
2)Bacteria
3)Eukaryota
3 methods of gene transfer used in bacteria that HGT can occur
through Correct Answers 1)transformation
2)conjugation
3)transduction
4 phyla that dominate the human microbiome Correct Answers
1)Actinobacteria
2)Bacteroidetes
3)Firmicutes
4)Proteobacteria
,A human consists of __________ more bacteria cells than
human cells and ____________ more microbial genes than
human genes Correct Answers 10x; 100x
Aerotolerant anarobe Correct Answers
Archezoan Scenario Correct Answers -one of the theories of
mitochondrial symbiosis
-A primitive mitochondrial eukaryote cell phagocytosed an a-
proteobacterium which led to evolution of mitochondrion
-fallen out of favour
Biofilm Correct Answers structure consisting of
polysaccharides surrounding groups of bacteria-important for
bacterial colonization of both environmental and host surfaces
Carboxysomes Correct Answers Microcompartments in
bacterial cytoplasm that contain enzymes involved in carbon
fixation
-found in cyanobacteria and chemotrophic bacteria
Causes of bacterial aging Correct Answers 1)Inheriting old cell
wall material at the "old" pole
2)Inheriting damaged DNA
3)Inheriting damaged proteins
4)Activation of damage defense systems (M) rather than growth
systems (G)
Define gram negative bacteria Correct Answers Lose crystal
violet stain (take colour of red counterstain) in Grams method of
staining
, -this is characteristic of bacteria that have cell wall composed of
thin layer of peptidolycan
Define gram positive bacteria Correct Answers Retain colour
of crystal violet stain
-this is characteristic of bacteria that have cell wall composed of
thick layer of peptidoglycan
Define symbiosis Correct Answers Living together or close
association of 2 dissimilar organisms, each of these organisms
being known as a symbiont
Do viruses carry genetic information? Correct Answers YES;
In form of DNA or RNA
Do we vaccinate against all 3 strains of influenza? Correct
Answers We oly vaccinate against A and B because they are the
only strains with seasonal outbreaks in humans
Does archaea form a monolayer or bilayer Correct Answers
Archaea forms monolayer unlike bacteria/eukaryotes that form
bilayer
-archaeal lipids are very heat/chemical resistant which
corresponds to their extreme habitats
Endospores Correct Answers A resistant asexual spore that
develops inside some bacterial cells
Endosymbiont Theory Definition Correct Answers Eukaryotes
evolved from prokaryotes based on similarities found between
bacteria and mitochondria
_____________ is abundant in the atmosphere but only a few
species of microbes can use it in this form Correct Answers
Nitrogen
2 main types of bacteria in human microbiome Correct Answers
1)Pathogenic Bacteria
2)Commensal Bacteria
2 mechanisms of mutations Correct Answers 1)Spontaneous
mutations
2)Induced via external agents
3 Domains Correct Answers 1)Archaea
2)Bacteria
3)Eukaryota
3 methods of gene transfer used in bacteria that HGT can occur
through Correct Answers 1)transformation
2)conjugation
3)transduction
4 phyla that dominate the human microbiome Correct Answers
1)Actinobacteria
2)Bacteroidetes
3)Firmicutes
4)Proteobacteria
,A human consists of __________ more bacteria cells than
human cells and ____________ more microbial genes than
human genes Correct Answers 10x; 100x
Aerotolerant anarobe Correct Answers
Archezoan Scenario Correct Answers -one of the theories of
mitochondrial symbiosis
-A primitive mitochondrial eukaryote cell phagocytosed an a-
proteobacterium which led to evolution of mitochondrion
-fallen out of favour
Biofilm Correct Answers structure consisting of
polysaccharides surrounding groups of bacteria-important for
bacterial colonization of both environmental and host surfaces
Carboxysomes Correct Answers Microcompartments in
bacterial cytoplasm that contain enzymes involved in carbon
fixation
-found in cyanobacteria and chemotrophic bacteria
Causes of bacterial aging Correct Answers 1)Inheriting old cell
wall material at the "old" pole
2)Inheriting damaged DNA
3)Inheriting damaged proteins
4)Activation of damage defense systems (M) rather than growth
systems (G)
Define gram negative bacteria Correct Answers Lose crystal
violet stain (take colour of red counterstain) in Grams method of
staining
, -this is characteristic of bacteria that have cell wall composed of
thin layer of peptidolycan
Define gram positive bacteria Correct Answers Retain colour
of crystal violet stain
-this is characteristic of bacteria that have cell wall composed of
thick layer of peptidoglycan
Define symbiosis Correct Answers Living together or close
association of 2 dissimilar organisms, each of these organisms
being known as a symbiont
Do viruses carry genetic information? Correct Answers YES;
In form of DNA or RNA
Do we vaccinate against all 3 strains of influenza? Correct
Answers We oly vaccinate against A and B because they are the
only strains with seasonal outbreaks in humans
Does archaea form a monolayer or bilayer Correct Answers
Archaea forms monolayer unlike bacteria/eukaryotes that form
bilayer
-archaeal lipids are very heat/chemical resistant which
corresponds to their extreme habitats
Endospores Correct Answers A resistant asexual spore that
develops inside some bacterial cells
Endosymbiont Theory Definition Correct Answers Eukaryotes
evolved from prokaryotes based on similarities found between
bacteria and mitochondria
