B1 TEST 1 Flashcards
How many chromosomes do prokaryotes have and how do they replicate?
1 DNA chromosome, no histones, replicate through binary fission.
What provides protection from outside world for almost all prokaryotes?
Cell wall AND plasma membrane
Protozoa and helminths are both types of what?
Parasites
What are Koch’s Postulates/Germ Theory (4 points)
1) If pathogen is cause of disease it must be able to be found in EVERY scenario disease is involved 2) If pathogen is cause of disease, you should be able to culture it from an infected patient (GROWN IN VITRO) 3) If pathogen is cause of disease, you should be able to infect a new host using the pathogen that you have cultured.. 4) If pathogen is cause of disease, you should be able to recover original pathogen from new infected host.
Fill in the blanks
Define core microbiome
commonly shared microbioal species among individuals at specific bodily sites
Define secondary microbiome
Microbial species that uniquely contribute to the diversity of individuals at specific body sites.
What type of environment (within humans) do gram negative bacteria prefer?
The type of bacteria prefer wet/moist conditions.
(hint: you’re upset to get wet)
These four types of tissue are usually considered sterile. List them.
1) Deep muscle
2) sinovial fluid
3) cerebrospinal fluid
4) blood
What is immune stimulation?
Exposure to low concentrations of anti-normal flora help provide protection against other bacterial pathogens, which allows response for foreign blood types, deep infections, etc.
What are some ways that normal flora prevent foreign invasion? What are some nutritional and metabolic benefits?
1) maintaining specific pH (low pH in vaginal tract)
2) physical occupancy (no room for invaders!)
3) secreting antibiotics and bacteriocins (proteins that can act against other bacteria)
Benefits
1) vitamin K synthesis
2) biotin synthesis
What is dysbiosis?
Disruption of the normal microbiota is called this.
What are the 3 common shapes of bacteria. Give both names for each type.
1) Cocci (spheres)
- clusters
- chains
- diplococci
2) Bacilli (rods)
3) Spirochetes (spirals)
Describe the unique features of gram + bacteria. What color does it turn in response to staining sequence?
1) THICK peptidoglycan (PTG) layer
2) Teichoic acid (major surface antigen and support structure. Found inside PTG.
3) Lipoteichoic acid
both (2) and (3) have some SLIGHT endotoxic properties associated with them
Describe the unique features of gram - bacteria. (6) What color does it turn in response to staining sequence?
1) THIN peptidoglycan layer
2) periplasmic space (between outer membrane and cytoplasmic membrane, hydrolytic ezymes found here)
3) Lipoproteins (such as beta-lactamase), located inside that periplasmic space
4) LPS or lipopolysaccharide
5) Endotoxin (lipid A)
6) Porin proteins ( allow entry of essential substances AND anitmicrobial drugs)
WILL TURN PINK
What is the backbone of peptidoglycan composed of? What component has the cross link/peptide interbridges attached?
alternating glycan chain of
1) (NAG) N-acetylglucosamine
2) (NAM) N-acetylmuramic acid
NAM has the cross-link/peptide interbridge attached
The cross-link reaction in the formation of peptidoglycan is catalyzed by these two enzymes? What class of enzymes do these belong to?
1) transpeptidase (responsible for cross-linking the tetrapeptides)
2) carboxypeptidases (turns 5-polypeptide into tetrapeptide and uses that energy to form peptide cross-link)
BOTH of these enzymes belong to the penicillin binding protein (PBP) class
List the two Penicillin binding proteins and the types of antibiotics that they are susceptible to.
1) Transpeptidase
2) Carboxypeptidase
Both susceptible to Beta-lactam (penicillin) and vancomycin antibiotics
What holds together the outermembrane in gram (-) bacteria? What can disrupt this?
Divalent Cations (Mg2+, Ca2+) hold this together through linkages b/w phosphates of lipopolysaccharides (LPS)
EDTA (Ethylenediaminetetraacetic acid) will destroy this outermembrane of gram - bacteria
Define antigenic.
something that causes a strong innate immune response. can induce fever and cause shock
(think LPS and endotoxin/lipid A)
What are the (4) steps of Gram Staining? What does each step do to both gram (+) and (-)?
1) Crystal Violet (dye tissue)
2) Gram Iodine (fix tissue to hold color)
3) Decolorizer/Alcohol/Acetone (disrupts lipids, washes off excess CV dye)
4) Safranin Red (dyes exposes tissue, counterstain)
commonly shared microbioal species among individuals at specific bodily sites
Define core microbiome
Microbial species that uniquely contribute to the diversity of individuals at specific body sites.
Define secondary microbiome
Exposure to low concentrations of anti-normal flora help provide protection against other bacterial pathogens, which allows response for foreign blood types, deep infections, etc.
What is immune stimulation?
Disruption of the normal microbiota is called this.
What is dysbiosis?
What is the compostion and function of bacteria’s external structure?
1) Capsule?
2) Glycocalyx?
3) Pili (fimbriae)?
4) Flagella?
What is the name of a biochemical reaction in which antibodies bind to the bacterial capsule for specific type of bacteria. This antibody reaction allows these species to be visualized under a microscope. If the reaction is positive, the capsule becomes slimy or mucoid appearance of a bacterial colony is usually evidence of capsule production
Quellung reaction
What is the benefit of a flagella?
Chemotaxis and motility
How can you tell whether a strain of bacteria has flagella?
Motility test in soft auger.
Stick inoculated need inside auger.
If bacteria spread across entire tube (looks cloudy) then they have flagella.
What external structure found on bacteria promotes adherence?
Pili (fimbriae)
What is the name for a bacterial tube that can transfer large segements of bacterials chromosomes between bacteria?
F pili (sex pili)
(hint: f*** pili)
How do many bacteria overcome the lack of environmental iron?
By secreting siderophores (small, high-affinity iron chelating compounds secreted by microorganisms such as bacteria, fungi and grasses. Siderophores are amongst the strongest soluble Fe binding agents known)
What are the starting and ending products of anaerobic bacteria metabolism?
Pyruvate–> ATP + NADH (fermenation)
