Introduction to microbiology Flashcards
define akaryote
no nucleus
define prokaryote
single cell nucleus lacking membrane bound nucleus.
define eukaryote
all other cells with nuclei
what percentage of cells in the human body are of human origin
10%
what type of organism do most microbiota in the human body consist of
bacteria.
what organism is commonly found on the hard surface of teeth
streptococcus mutans
what organism is commonly found on the soft tissues of the mouth
streptococcus salivarius
what vitamin do the bacteria of the gut provide us with
vitamin K.
what chemical/ element required for life is produced by bacteria of the body
nitrogen.
what term is used to describe bacteria which cause disease
pathogenic or virulence
do all bacteria in the body cause harm
No.
what is used to identify or determine whether an organism causes disease or not.
Koch’s postulates.
what is stated in koch’s postulates (4 points) for an organism
The causative organism must be isolated from every individual suffering from the disease in question.
The causative organism must be cultivated artificially in pure culture.
When the causative organism is inoculated from pure culture, the typical symptoms of the infection must result.
The causative organism must be recoverable from individuals who are infected experimentally
what is stated in koch’s postulates for virulent genes. (6 factors)
The gene encoding the trait of interest should be present and transcribed/translated in a virulent strain.
the gene encoding the trait of interest should NOT be present or should be silent in a strain that does not cause disease;
disruption of the gene in a virulent strain should result in the formation of a strain that is incapable of casing disease;
introduction of the gene into a strain that previously did not cause disease should transform the strain into one that does cause disease;
the gene must be expressed during infection;
antibodies raised against the gene product
or the appropriate cell-mediated immunity
should protect experimental subjects
against disease.
what are the main issues with Koch’s postulates
difficulty of isolation the causative agent.
impossible to grow some
ethical objections
what is the basic structure of a virus
nuclei acid core with a protein coat.
some may have an envelope.
are viruses intracellular or exracellular.
Viruses are obligate intracellular parasites.
how do reteroviruses cause disease.
Retroviruses are unusual in that the virion carries an RNA copy of the genome but upon infection of a host cell a cDNA copy of the virus genome is made using the enzyme reverse transcriptase and put into the human genome.
what organism causes plant infections
Viroids.
what organism is spongiform encephalopathies classed as
prion
define viroids
naked, infectious RNA molecules that are not associated with any proteins.
are fungi, prokaryotic, eukaryotic or akaryotic.
eukaryotic
