3- Bacterial Gentics Flashcards
carry genetic information In bacteria
Chromosome and plasmid
What are the commensals
Give Ex
Harmless microbes that harbour on a living host without causing
any injury to the host eg. Normal bacterial flora
✔️or✖️
TORCH infections
Transmissed via the birth canal without causing congenital malformation in
the baby
✖️
Group B Streptococcus, Neisseria gonorrhoeae, Transmissed via the birth canal
directly bind to the sugar residues (glycolipids or
glycoproteins) on host cells.
Fimbriae or pili
Enhancement of virulence is known as
Exaltation
is the natural habitat in which the organism lives and multiplies.
reservoir
Infections occurring in hospitals are called
Nosocomial infections
Exchange of genetic information through a hollow tube from the donor cell (F+) to the recipient (F-) bacterial cell.
Conjugation
(One of Horizontal gene transfer types)
✔️or✖️
Vibrio cholerae carry one chromosomes
✖️
Two
virus that replicates inside a bacterial cell
bacteriophage
after entering the cell, the phage DNA,
rather than replicating autonomously, can integrate into the chromosome of the host cell (prophage).
and the phage DNA replicates as part of the host’s chromosome.
Temperate phage
In contrast to viral infection of vertebrate cells, in which the entire virus is taken up by the cell and its nucleic
acid is released intracellularly
The replicative cycle of prophage :
1-attachment of the phage to receptors
2-injection of the nucleic acid into the bacterial cell
What are Saprophytes
Free-living microbes that live on dead or decaying organic
matter. Normally not cause human infection
Infective dose of Shigella sps (cause dysentry) - 10 bacilli
✔️or✖️
✔️
is the entry of bacteria into host cells, leading to spread within the host tissues.
Invasion
(play role in bacterial pathogenicity)
Recount Mode of transmission
§ Contact eg. Sexual contact
§ Inhalation eg. secretions from the nose
§ Ingestion eg. Food borne infections
§ Inoculation eg. Animal bite
§ Blood borne infections eg. Needle prick
§ Vector borne – eg. Mosquitos
§ Ve r t i c a l transmission -(hereditary)
What is the reservoir of spores of Anthrax bacilli
Soil (Non living reservoir)
Reduction of virulence
Attenuation
refers to person, animal, or object from which a microorganism is transmitted to the host.
Source of infection
Define the Opportunistic pathogens
Microbes capable of causing disease only in immunocompromised people.
are antibiotic like substance secreted by bacterium that inhibits
growth of other baceteria Eg. Colicin secreted by Escerichia coli
Bacteriocins
Nonlysogenic bacteria can be made lysogenic by infection with a Virulent phage.
✔️or✖️
✖️
temperate phage.
Transformation of DNA from one bacterium to another by a bacteriophage
Transduction (one type of Horizontal gene transfer)
Recount The Applications Of Transduction
Give 1 Ex
Transfer drug resistance genes
(Ex.Plasmid coded pencillin resistance in Staphylococci)
Genetic engineering
lysogenic conversion is
Acquisition bacteria of prophage properties
transfer of bacteriocin producing genes
is the application of ….
Conjugation
Mutation occur by mutagens such as :
(UV rays,
5 bromouracil,
alkylating agents)
The Central Dogma of molecular biology is
DNA
Plasmids are Intrachromosomal genetic elements .
✔️or✖️
✖️
Extra chromosomal elements
What is the difference between
Fertility plasmid
Resistance plasmid
Col plasmid
-F- plasmid codes for sex pili
-R- plasmid code for resistance to antibiotics
- Col plasmid codes for bacteriocin
Give Ex for bacteriocin
Colicin
Which is secreted by Escerichia coli
Infection of a bacterium results in the death of the cell by lysis
Virulent phage
It consists of a piece of nucleic acid encapsulated in a protective protein coat.
bacteriophage (phage)
Uptake of DNA from surrounding medium by bacterial cell &
incorporated into its chromosome
Transformation
What the bacteria called when carry a prophage.
Lysogenic bacteria
The association of prophage and bacterial cells is highly unstable
✔️or✖️
✖️
Stable
Explain the destabilization steps of prophage and bacterial cells that occurs by various treatments such as exposure to ultraviolet light,
1- repression of prophage gene
2- excision of prophage from the host chromosome
3- production of progeny phage particles
Define Parasites
Microbes that live on a host and derive ATP and harm the host
Define Infection term
Process in which a pathogenic organism enters,
by invades the normal anatomical barrier of the host; resulting in disease
Re-infection is
subsequent infection by the same microbe.
Iatrogenic infections is
Infections induced during diagnosis or treatment
by physician or other health care workers
Human reservoirs called
Carrier
Bacterial toxins are of two types
List their names and characteristics
ENDOTOXINS :
- integral part of cell wall
- produced by gram +ive organisms
- heat liable
- can produce toxoids
EXOTOXINS :
- released from the cell
- produced by both gram organisms
- heat stable
- can’t produce toxoids
Invasion produces two types of lesions
List them with their Ex
Generalized lesions – produced by highly invasive pathogens e.g. Streptococcus
Localised lesions – produced by less invasive pathogens e.g. Staphylococcus
