N4110 Microbiology Week 2_Else
Polyhedral capsids
Capsid is a polyhedral icosahedron (20-sided structure with 12 vertices) surrounding a nucleic acid Poliovirus, rhinovirus
Helical capsid
Capsid is cylindrical or rod-shaped with genome fitting just inside the length of the capsid Tobacco mosaic virus, Ebola virus
Steps of the lytic cycle
Attachment, entry/penetration, biosynthesis of new viral components, maturation, lysis
Steps of the lysogenic cycle
Attachment, penetration, phage DNA incorporated, replication, phase DNA excised and enters the lytic cycle at biosynthesis of new viral components and ending in lysis
Which of the following species of bacteria is known to live in the stomachs and duodenums of many people and is a leading cause of ulcers, gastritis, and stomach cancer? Helicobacter pylori, Salmonella typhi, Vibrio cholerae, Haemophilus influenzae
Helicobacter pylori
Neutralism
Neither organism is affected
Oxidase Positive
Bacteria which use oxygen as the final electron acceptor in aerobic respiration
Pathogen
A disease-causing agent that disrupts the normal physiology of the infected organism
Fermentation
A metabolic process that produces chemical changes in organic substrates through the action of enzymes
Parasite
A microorganism that depends on another living organism host for its life cycle; it may or may not cause any disease or affect the health of the host
Motile
Ability of bacteria to move independently using metabolic energy
Oligotroph
An organism that can survive in a nutrient-poor environment
Eutroph/copiotroph
An organism that requires a copious amount of organic nutrients
Mechanical vector
Arthropod carries a viral pathogen on the outside of its body, transmits via physical contact
Biological vector
Arthropod carries viral pathogen within its body and transmits it to a new host via bites
Among the bacterial species that live in the human GI tract, which one of the following bacteria groups comprises 30% of the population? Bacteriodes, Spirochetes, Fusobacterium, Cytophaga
Bacteriodes
Viruses that infect bacteria are referred to as... Bacteriophages, retro viruses, bacteriophillic viruses, enveloped virsus
Bacteriophages
Complex viral shape
Bacteriophages with features of polyhedral and helical viruses Genome located within polyhedral head, sheath connects head to tail fibers Poxviruses (brick shaped, complex surfaces)
Mutualism
Both organisms benefit (e.g., E. coli in human GI tract)
Viruses contain genetic material in the form of DNA and RNA but not both, both DNA and RNA, ATP and polymerase enzymes, none
DNA or RNA but not both
Fastidious
Difficult to culture, complicated nutritional requirements
How are Chlamydia species classified? Gram-negative obligate intracellular pathogens, Gram-negative pneumotrophes, Gram-negative non-proteobacteria, Gram-positive obligate intracellular pathogens
Gram-negative obligate intracellular pathogens
Retroviral life cycle
HIV fuses to host cell surface HIV RNA, reverse transcriptase, integrase, and other viral proteins enter the host cell Viral DNA is formed by reverse transcription Viral DNA is transported across the nucleus and integrates into the host DNA New viral DNA is used as genomic RNA and to make viral proteins New viral RNA and proteins move to the cell surface and a new, immature HIV forms The virus matures when protease release the proteins that form the mature HIV
Qualities of viruses
Infectious, acellular pathogens Obligate intracellular parasites with host and cell-type specificity DNA or RNA genome (never both) Genome is surrounded by a protein capsid and sometimes a phospholipid membrane studded with viral glycoproteins Lack genes for many products needed for successful reproduction, requiring exploitation of host-cell genomes to reproduce
The bacteria Staphylococcos aureus is an organism that causes frequent pathogenic infections in humans and belongs to which group of bacteria? Low G+C Gram positive Bacilli, Low C+B Gram positive Lactobacillales, High G+C Gram negative Bacilli, High G+C Gram negative Cocci
Low G+C Gram positive Bacilli
Highly virulent viruses go through a life cycle termed: Lytic Cycle Lysogenic Cycle
Lytic Cycle
Which one of the following terms best describes the relationship between humans and the strain of E. coli that lives in the human GI tract, consumes nutrients from the foods we eat, and synthesizes vitamin K? Mutualism, comensalism, parasitism, neutralism
Mutualism
Facultative
Occurs optionally in response to various circumstances or environment
Parasitism
One organism benefits, the other is harmed
Commensalism
One organism benefits, the other is unaffected
Ammensalism
One organism is unaffected, but harms the other
Malaria is caused by Plasmodium, Paramecium, Staphylococcus auereus, Vibrio cholera
Plasmodium
Nitrogen fixation
Prokaryotic process of converting atmospheric nitrogen into ammonia
Carbon fixation
Prokaryotic process of converting carbon dioxide to organic carbon products; animals need prokaryotes to do this
Obligate intracellular pathogen
Relies upon host cell intracellular resources for its reproductive cycle (cannot reproduce outside of host cell)
Anaerobic
Requires an absence of free oxygen
Aerobic
Requires free oxygen
Microaerophilic
Requries low levels of free oxygen
Obligate
Restricted to a particular function or mode of life
Pleiomorphic
The ability of a microorganism to change shape under varying conditions
Zoonose
Virus that can be transmitted from an animal to a human host
Bacteriophage
Virus that infects bacteria
Viruses as infection-causing
Viruses are obligate intracellular parasites because they are not alive (because they are acellular) Virions - new virus particles formed in the host cell
Naked/nonenveloped viruses
Viruses formed from only a nucleic acid and capsid
Enveloped viruses
Viruses formed with a nucleic acid-paced capsid surrounded by a lipid layer
A virus that lives out a lysogenic cycle... incorporates its genes with the host cell's DNA and is replicated when the cell replicates, shuts down replication of the host cell's DNA, Causes the host cell to quickly die and shed new virus, Is a far more virulent virus
incorporates its genes with the host cell's DNA and is replicated when the cell replicates