Intro to Microbiology Flashcards
(27 cards)
Name two types of prokaryotes and their defining feature
- Bacteria
- Archaea
They have no nucleus.
Name two types of unicellular eukaryotes.
- Parasites
- Fungi (yeast)
Name two types of multicellular eukaryotes
- Parasites
- Fungi (mold)
Unlike prokaryotes, eukaryotes have…
a nucleus and organelles
How do prokaryotes reproduce?
Binary fission (asexual, no mitosis) and clonal expansion
How do viruses reproduce?
Fission (asexual) and clonal expansion (using host machinery)
Some eukaryotes like yeast reproduce by binary fission and clonal expansion, however most eukaryotes reproduce…
SEXUALLY (mitosis occurs)
What is “bacterial sex” or “bacterial conjugation”?
When a bacterium transfers extra-chromosomal DNA material (plasmid) to another bacterium via pili.
How are antimicrobial resistance genes transmitted between bacteria?
Through bacterial conjugation (bacterial “sex”).
What are 3 possible arrangements of cocci prokaryotes?
- Diplococci (2 cocci)
- Staphylococci (grape cluster)
- Streptococci (chain)
What are 3 possible arrangements for bacilli prokaryotes?
- Diplobacilli (2 bacilli)
- Streptobacilli (chain)
- Palisades
When does bacterial colonization of the human body occur?
At birth, through contact with maternal vaginorectal tissues and skin flora.
Gram’s stain: Crystal violet dye (blue/purple) is fixed to:
a) gram positive bacteria
b) gram negative bacteria
a) gram positive
Gram’s stain: Safranin dye (red/pink) is binds to:
a) gram positive bacteria
b) gram negative bacteria
b) gram negative bacteria
Compare the following features of gram+ and gram- bacterial walls:
a) Thickness
b) Teichoic acids
c) Presence of LPS
d) Stain
e) Susceptibility to penicillin
Gram Positive:
a) Thick (many layers)
b) Teichoic acids are present
c) LPS are absent (no outer membrane)
d) Stains blue/purple (crystal violet)
e) More susceptible to penicillin
Gram Negative:
a) Thin (1-2 layers)
b) Teichoic acids are absent
c) LPS are present (outer membrane)
d) Stains red/pink (safranin)
e) Less susceptible to penicillin (outer membrane blocks drugs)
3 gram positive exceptions to “masculine-sounding” names
- Listeria spp.
- Nocardia spp.
- Gemella spp.
These are 3 “female-sounding” yet gram-positive bacteria (exceptions).
5 gram negative exceptions to “female-sounding” names
- Anything with “bacter” in the name
- Anything with “monas” in the name
- Haemophilus spp.
- Vibrio spp.
- Proteus spp.
These are 5 “male-sounding” yet gram-negative bacteria (exceptions).
3 types of bacteria without cell walls
- Mycoplasma spp.
- Chlamydia spp.
- Chlamydophila spp.
Virulence factors: 3 examples of physical defence barriers and adherence
- Capsule (protects against antibodies)
- Biofilms (bacteria live in self-produced matrix on surfaces)
- Fimbriae (hair projections allowing the bacterium to move)
Name an example of bacterium with one of the following virulence factors:
a) Capsule
b) Biofilms
c) Fimbriae
a) Capsule: Streptococcus pneumoniae
b) Biofilm: Staphylococcus epidermis
c) Fimbriae: Escherichia coli
Why is the outer cell membrane of LPS considered a virulence factor (gram-)?
Lipid A in this LPS membrane is an endotoxin that triggers a strong immune response, resulting in:
- cytokine release
- fever
- shock
Minimum Inhibitory Concentration (MIC)
The lowest concentration of an antibiotic needed to prevent or inhibit the growth of a microorganism in the laboratory
Antibiotic resistance genes give rise to proteins which… (3)
- Are secreted and cleave antibiotics
- Form mutated binding sites for antibiotics (such that the antibiotics cannot bind effectively)
- Do not allow antibiotics to enter the bacterium
Two major subdivisions of fungi
- Yeasts
- Moulds
