microbiology Flashcards
define prokaryote
a single-cell organism whose cell lacks a nucleus and other membrane-bound organelles
why is it important to understand microbiology
- understand how diagnostic tests work
- understand how vaccines work, communicate risk and explain why vaccines are important
- understand rapid developments in field
define pandemic
worldwide outbreak spreading of disease
define epidemic
disease outbreak that is rapidly spreading in a limited region
define endemic
disease belonging or native to a particular people or country
or
of a disease regularly occurring within an area or community.
define antigenic drift
genetic variation in viruses, arising from the accumulation of mutations in the virus genes that code for virus-surface proteins that host antibodies recognize
or
evolutionary accumulation of amino acid substitutions in viral proteins selected by host adaptive immune systems as the virus circulates in a population
what does AMR stand for
anti microbial resistance
what does ABR stand for
antibiotic resistance
define antibiotic resistance
bacteria resistance to antibiotics due to either through a new genetic change that helps the bacterium survive, or by getting DNA from a bacterium that is already resistant.
how does ABR AND AMR differ
- Antibiotic resistance refers to bacteria resisting antibiotics.
- Antimicrobial resistance (AMR) describes the opposition of any microbe to the drugs that scientists created to kill them.
what are the 5 main cases of infectious agents relating to communicable disease
viruses
bacteria
fungi
parasites
prions
describe the structure of a virus
- attachement protein
- envelope
- capsid
- genome (DNA/RNA)
describe the lifecycle of virus
- virus particle adheres to surface of target cell
- virus enters cell, protein coat dissolves, genetic material released
- genetic material replicates (using host cell enzymes or enzymes from virus)
- new virus particles are synthesised by host ribosomes
- new infectious vires are assembles and leave cell
what is the difference between prokaryote and eukaryote cell + structure difference
Prokaryotes are always unicellular, while eukaryotes are often multi-celled organisms.
Eukaryote are 100-10000 x larger.
what are 2 ways to classify a bacteria
- by shape when viewed under microscope
- by cell wall structure using gram strain
what is gram stain
If bacteria are present on a Gram stain slide, a medical laboratory scientist classifies them as gram-negative or gram-positive based on which color they turn under a series of stains
what are the 4 steps of gram stain
Applying a primary stain (crystal violet). (60s)
Adding a mordant (Gram’s iodine) (60s)
Rapid decolorization with ethanol, acetone or a mixture of both. (5-10s)
Counterstaining with safranin (45s)
what does it mean if the stain turns pink
it is Gram-negative bacteria, they have cell walls with thin layers of peptidoglycan (10% of the cell wall) and high lipid (fatty acid) content
what does it mean if the stain turns purple
it is Gram-positive bacteria, they have cell walls that contain thick layers of peptidoglycan, a substance that forms the cell walls of many bacteria.
define mould
multinucleated, filamentous fungi composed of hyphae (branching filaments)
define yeast
unicellular (single-celled) organisms that belong to the Fungi kingdom
what are the 2 classes of fungi
mould and yeast
what is the biological definition of parasite
an organism that lives on or in a host organism and gets its food from or at the expense of its host.
what is the medical definition of parasite
dA plant or an animal organism that lives in or on another and takes its nourishment from that other organism.
