Introduction To Microbiology Flashcards
Definition of taxonomy
Systematic classification of organisms
Definition of obligate aerobes
Organism that needs O2 to grow
Definition of facultative anaerobes
Organism that makes ATP by aerobic respiration if O2 present
Can switch to fermentation/aerobic respiration if O2 absent
Definition of obligate anaerobes
Organisms that die in the presence of O2
Definition of nucleocapsid
Capsid of virus with the enclosed nucleic acid
Definition of trophozoite
Metabolically active growth stage in protozoa life cycle
Definition of cyst
Dormant stage in protozoa life cycle
Definition of yeast
Single celled fungi
Definition of hyphae
Long branching filamentous structure in fungi
Collectively known as mycelium
Definition of porins
Facilitate movement of charged molecules across the bacterial membrane
Definition of antiphagocytic
Impeding/preventing action of phagocytes/phagocytosis
Definition of conjugation
Sex pili used to form a bridge between 2 bacteria to exchange genetic material
Definition of transduction
Process by which foreign DNA is introduced into a bacterial cell by a virus or viral vector
Definition of transformation
Genetic alteration of a cell resulting from the direct uptake and incorporation of exogenous genetic material from its surroundings through the cell membrane
Definition of tropism
Cells and tissues of a host that support growth of the bacterium/virus
Definition of serotype
Variation in bacteria/viruses based on cell surface antigens
What are the 5 types of microbe
Parasites (Helminths, Protozoa) Fungi Bacteria Viruses prions
Characteristics of viruses
- Cells
- Nucleic acid
- Type of nucleus
- Ribosomes
- Membrane bound organelles
- Nature of outer surface
- Method of replication
No cells DNA or RNA No nucleus No ribosomes No membrane bound organelles Protein capsid and lipoprotein envelope Needs host machinery to reproduce
Characteristics of bacteria
- Cells
- Nucleic acid
- Type of nucleus
- Ribosomes
- Membrane bound organelles
- Nature of outer surface
- Method of replication
Has cells DNA and RNA Prokaryotic 70S no membrane bound organelles Rigid cell wall with peptodoglycan Binary fission
Characteristics of fungi
- Cells
- Nucleic acid
- Type of nucleus
- Ribsomes
- Membrane bound organelles
- Nature of outer surface
- Method of replication
Has cells DNA and RNA Eukaryotic 80S Has membrane bound organelles Rigid chitin cell wall Budding/mitosis
Characteristics of Protozoa/helminths
- Cells
- Nucleic acid
- Type of nucleus
- Ribsomes
- Membrane bound organelles
- Nature of outer surface
- Method of replication
Has cells DNA and RNA Eukaryotic 80S Has membrane bound organelles Flexible membrane Mitosis
Characteristics of macro parasites
- Organism
- Size
- Replication product
- Generation time
- Immunity
Helminths Big (naked eye) Outside host (eggs, larvae) Long Weak and short lived
If progeny of macroparasites grow in an organism, can lead to large no of parasites in the body => cause infection
Characteristics of micro parasites
- Organism
- Size
- Replication product
- Generation time
- Immunity
Viruses, bacteria, Protozoa and fungi Small (need a microscope) Within the host Short Can develop immunity
How do you classify microbes
How do you name viruses
Microbes names with binomial Linen system (genus, species)
Viruses have 1 name
Characteristics of bacteria used in classification
- staining
- shape
- spores
- metabolism
- enzyme, toxin prod
- DNA sequencing
Staining
-G+-ve
Shape
-Bacilli/Cocci/Spirilla
Spores
-Adhere end to end => chain => long branched stalk => spore release
Metabolism
-Obligate/facultative aerobes/anaerobes
Enzyme, toxin prod
DNA sequencing
What are the 4 essential bacterial components
-What are their functions
Cell wall
- Peptidoglycan (tetra AA, glycan)
- Shape, metabolism, virulence, antigenicity
Plasma membrane
- Barrier to molecules
- Energy gen
Nucleoid
-DNA here
Ribosome
-Protein synth
How do you do a Gram stain
What color is G+ve/-ve bacteria
Primary stain
Fixant
Decolourizer
Counter stain
G+ve => blue
G-ve => red
What bacteria do not stain
What stain do you use
Acid fast bacteria, mycobacteria
-Ziehl Nielsen
What are the properties of Gram +ve bacteria
- Peptidoglycan
- Outer membrane
- LPS?
- Teichoic?
- Porins
Thick peptidoglycan layer No outer membrane No LPS, low lipid lipoprotein Teichoic/lipoteichoic acid No porins
What are the properties of Gram -ve bacteria
- Peptidoglycan
- Outer membrane
- LPS?
- Teichoic?
- Porins
Thin peptidoglycan Thick outer membrane LPS, high lipid lipoprotein No teichoic/lipoteichoic acid Porins allow charged molecule mv
What are the non essential bacterial components
-what is their function
Capsule
- polysaccharide
- antigenic, ID component, valence, antiphagocytic, adherence
Flagella
- fixed no/location specific for movement
- antigenic, ID component
Pili/fimbirae
- thin filaments
- Normal => host cell attachment
- Sex => bridge in conjugation
Plasmid
- circular dsDNA, can self replicate
- AB resistance genes transmitted via conjugation, transformation, transduction
Spores
- Some G+ve, DNA surrounded by keratin
- formed in adverse conditions
- heat, chemical, desiccant resistance
How would you deal with spores
- heat resistance
- chemical resistance
- long survival rate
Heat resistant
-autoclave at 121C
Chemical resistant
-sporicides
Long survival rate
-can live in contaminated soil
What are the properties of helminths
- lifecycle
- cells
- location
- transmission (Direct/Indirect)
Lifecycle
-complex egg => larva => adult
Cells
-multicellular
Location
-often infest GI
Transmission (Direct)
-Swallowing/skin penetration
Transmission (Indirect)
-Non human hosts
What are the properties of protozoa
- lifecycle
- cells
- location
- transmission (Direct/Indirect)
LIfecycle
- Trophozoite stage => cyst stage
- short regeneration time
Cells
-unicellular (large no of progeny)
Location
-free living/hosts needed in life cycle
Transmission (Direct)
-Ingestion
Transmission (Indirect)
-Insect vectors
What are the properties of fungi
- cells
- cell wall
- location
Cells
- yeast = uni
- hyphae = branched, multicellular CAN BE BOTH
Cell wall
-Chitin
Location
-Environment/normal flora
What are the 3 types of fungal disease
Superficial
-on hair shaft, dead skin
Cutaneous
-epidermis, hair, nails
Opportunistic
-internal organs
What are the essential viral components
- what types of genetic material exist
- what shapes exist
DNA/RNA
- virion production in host => +ve ssmRNA
- can be +ve/-ve/ss/ds
- DNA large => encode own enzymes
- DNA small => use host enzymes
- RNA => encode RNA dependent RNA polymerase
- Retro => code reverse transcriptase
Capsid core
- Capsomeres protect genome
- Used to attach to host receptors in naked
- Antigenic, AB target
- Icosahedral (closed)
- Helical (open)
- Complex (POXVIRUSES)
What are the non essential viral components
-why is it important
Lipid envelope
-spike glycoproteins
-determines stability and transmission
Naked => stable, food and water transmission
Enveloped => doesnt persist in environment
What are the 6 steps in viral replication
Attach to cell receptors/proteins via spikes/coat
Overcome membrane via fusion/translocation/receptor endocytosis
Revealing genome
Ribosomes, Golgi produce viral proteins
Assembly of new visions => nucleocapsid
Release of viruses from host
What 4 cell functions are needed for viral replication
Machinery for viral mRNA translation
Enzymes for genome replication, vision assembly
Transport pathways to reach replication sites
Energy source
