Part two Flashcards
Define Toxins
a chemical produced by pathogens that harm tissue or trigger hosts immune response that causes damage
Exotoxins are gram positive T/F
TRUE :)
Define an exotoxin
Proteins secreted by live pathogen and attack/destroy cellular and extracellular structures
Examples of Exotoxins:
MRSA/Staph Auerous: cellulitis, abcesses, facilitis, and invasive infections (h1n1, pneumonia)
C-DIFF: grav positive killer, necrotic colon, GI symptoms and inflammation
Anthrax: makes exotoxins (inhalation)
Define an Endotoxin
a gram negative bacteria; released after cell dies and the cell wall is altered ; contains LPS
What is LPS and what is its function?
lipopolysaccharides found in gram negative endotoxins.
- huge role in infection
- causes acute inflammation and activites macrophages, neutrophils and pyrogens.
What happens when there is to much LPS?
toxic to the body!!!!
- causes to much activity from the immune system (can be induced by antimicrobial drugs)
- systemic infections, blood coagulation = increased inflammation, drop of BP = shock and organ failure
Cytoplasmic DNA
prokaryotic chromosome; one large circular molecule
HAPLOID
no nuculear membrane
may have plasmids (small chromosomes)
What are the three roles of cytoplasmic DNA?
1) contains genetic material
2) transcription
3) replication
What is the function of ribosomes?
process of translation (protein synthesis)
True or false: Prokaryotic ribosomes are bigger then eukaryotic
FALSE ; they are smaller
P= 70S
E=80S
Prokaryotic ribosomes are __S and they can be found in ________
70S / eukaryotes mitchondria
What is the power house of the cell
….you should know this…
Define an endospore
formed by vegetative cells in response to environmental signals that indicate a limiting factor for vegetative growth
Are endospores formed by gram positive or gram negative bacteria?
gram positive
What stress are endospores resistant to?
- temperature
- irridation
- acids
- disinfectants
When do endospores germinate?
when the environmental stimulus STOPS
Define horizontal gene transfer
acquiring genes from other microbes of the same generations (donor cells contribute part of the genome to a recipient cell)
What are the 3 types of gene transfer?
- Transformation
- Transduction
- Conjugation
Define Transformation
naturally competent bacteria are able to take up exogenous DNA and undergo the genetic transformation
Cells that take up DNA are competent - results in alteration of cell wall and membrane to allow DNA entry
Eg. streptococcus, heamophilus, bacillus staphococcous, and pseudomonas
What is transduction and what mediates it?
Gene transfer from donor to recipient by bacteriophage. Attaches to host bacterial host cells, injects genome, and directs the cell to synthesize new phages.
What are the steps in generalized transduction?
- Infection to donor
- Phage replication and degradation of host
- assembly of phage particles
- Realease of phage
- Recombination into host DNA
Gene transfer from a donor to a recipient by direct/physical contact between cells (mediated by pilli)
CONJUGATION
what are the maiting types in conjugation?
Fertility plasmids + = the donor
Fertility plasmid - = the recipient
