MICR 271 MIDTERM EXAM QUESTIONS
WITH CERTIFIED ANSWERS
What is the ability of some viruses to incorporate into the host genome called - Answer-
In animal viruses-viral genome integration
In bacterial viruses-lysogeny
How do viruses exchange genetic material between different species? - Answer-
Through viral genome integration, once the virus excises from the host genome it can
pick up host genes which can be incorportated into the next host it infects
T/F: The origin of viruses is well established - Answer-False
T/F: Viral genes represent a relatively small proportion of total genetic diversity on
earth? - Answer-False
T/F: Viruses are dependent upon their host cells in order to replicate? - Answer-True
T/F: Viruses have an important role in carrying genetic information between different
species - Answer-True
What is the hierarchy of recognized bacterial taxa?1 - Answer-Kingdom, phylum, class,
order, family, genus, species
What is the hieracrchy of recognized viral taxa? - Answer-Order, Family, Subfamily,
Genus, Species
extremophiles - Answer-Organisms that live in harsh conditions
Selective pressure defintition - Answer-Any phenomena that alters the behaviour and
fitness of a living organism in its environment
4 phyla that dominate the human microbiome - Answer-1)Actinobacteria
2)Bacteroidetes
3)Firmicutes
4)Proteobacteria
2 main types of bacteria in human microbiome - Answer-1)Pathogenic Bacteria
2)Commensal Bacteria
Explain Commensal bacteria - Answer--non pathogenic
-symbiotic relationship with host
Processes of bacteria acquiring genetic diversity (2) - Answer-1)Mutations
, 2)Gene transfer or genetic recombination
2 mechanisms of mutations - Answer-1)Spontaneous mutations
2)Induced via external agents
3 methods of gene transfer used in bacteria that HGT can occur through - Answer-
1)transformation
2)conjugation
3)transduction
Transposition definition - Answer-jumping of genes from one chromosomal location to
another within an organism
-method of gene transfer used by bacteria
Mechanisms bacteria use to obtain resistance to antibiotics (4) - Answer-1)Target
protection-expression of molecule impairing antibiotic recognition & activity
2)Target substitution-alteration of amino acid sequences in target sites in bacteria
3)Prevention of intercellular antibiotic accumulation-increased expression of bacterial
efflux mecahnisms which result in increased ability of bacteria to remove antibiotics
from cell
4)Antibiotic detoxification-increased ability of bacteria to alter or degrade antibiotic,
reducing its effects
What are 2 major ways humans have impacted microbial diversity? - Answer-1)Climate
Change
2)Use of antibiotics
Factors to consider when using vaccines to control incidence of pathogens: - Answer-
1)Herd immunity-maximum vaccine efficiency relies on most of the population to be
immunized
2)Limited window of effectiveness (ex flu changes rapidly)
3)Selective pressure allows resistant pathogens to outcompete non resistant pathogens
Increasing genome complexity correlates with ___________________ - Answer-
increasing structural and metabolic complexity
What is the main feature used to divide viruses into 2 main categories? - Answer-
presence or absence of envelope
What is a virus that only infects bacteria called? - Answer-bacteriophage
T/F: The structure of a virus dictates host specificity - Answer-False
What are the 2 main virus structures? - Answer-1)Nonenveloped virus
2)Enveloped virus
WITH CERTIFIED ANSWERS
What is the ability of some viruses to incorporate into the host genome called - Answer-
In animal viruses-viral genome integration
In bacterial viruses-lysogeny
How do viruses exchange genetic material between different species? - Answer-
Through viral genome integration, once the virus excises from the host genome it can
pick up host genes which can be incorportated into the next host it infects
T/F: The origin of viruses is well established - Answer-False
T/F: Viral genes represent a relatively small proportion of total genetic diversity on
earth? - Answer-False
T/F: Viruses are dependent upon their host cells in order to replicate? - Answer-True
T/F: Viruses have an important role in carrying genetic information between different
species - Answer-True
What is the hierarchy of recognized bacterial taxa?1 - Answer-Kingdom, phylum, class,
order, family, genus, species
What is the hieracrchy of recognized viral taxa? - Answer-Order, Family, Subfamily,
Genus, Species
extremophiles - Answer-Organisms that live in harsh conditions
Selective pressure defintition - Answer-Any phenomena that alters the behaviour and
fitness of a living organism in its environment
4 phyla that dominate the human microbiome - Answer-1)Actinobacteria
2)Bacteroidetes
3)Firmicutes
4)Proteobacteria
2 main types of bacteria in human microbiome - Answer-1)Pathogenic Bacteria
2)Commensal Bacteria
Explain Commensal bacteria - Answer--non pathogenic
-symbiotic relationship with host
Processes of bacteria acquiring genetic diversity (2) - Answer-1)Mutations
, 2)Gene transfer or genetic recombination
2 mechanisms of mutations - Answer-1)Spontaneous mutations
2)Induced via external agents
3 methods of gene transfer used in bacteria that HGT can occur through - Answer-
1)transformation
2)conjugation
3)transduction
Transposition definition - Answer-jumping of genes from one chromosomal location to
another within an organism
-method of gene transfer used by bacteria
Mechanisms bacteria use to obtain resistance to antibiotics (4) - Answer-1)Target
protection-expression of molecule impairing antibiotic recognition & activity
2)Target substitution-alteration of amino acid sequences in target sites in bacteria
3)Prevention of intercellular antibiotic accumulation-increased expression of bacterial
efflux mecahnisms which result in increased ability of bacteria to remove antibiotics
from cell
4)Antibiotic detoxification-increased ability of bacteria to alter or degrade antibiotic,
reducing its effects
What are 2 major ways humans have impacted microbial diversity? - Answer-1)Climate
Change
2)Use of antibiotics
Factors to consider when using vaccines to control incidence of pathogens: - Answer-
1)Herd immunity-maximum vaccine efficiency relies on most of the population to be
immunized
2)Limited window of effectiveness (ex flu changes rapidly)
3)Selective pressure allows resistant pathogens to outcompete non resistant pathogens
Increasing genome complexity correlates with ___________________ - Answer-
increasing structural and metabolic complexity
What is the main feature used to divide viruses into 2 main categories? - Answer-
presence or absence of envelope
What is a virus that only infects bacteria called? - Answer-bacteriophage
T/F: The structure of a virus dictates host specificity - Answer-False
What are the 2 main virus structures? - Answer-1)Nonenveloped virus
2)Enveloped virus
