| What do we mean by epidemiology? | We answer the three questions: Where, When, and Who is affected+ modes of transmission of diseases caused by any bacteria/virus.
For example: epidemio of TB is in india, in 2022 for the underprevelaged people living in rural areas. |
| What is an endemic? | Is a disease spread but limited to a particular region
For example: Malta fever/ Brucellosis which is usually found in the mediterranean due to the large consumption of diary products there. |
| What is an epidemic? | Its a disease which came from outside of a region where it usually doesn't exist.
For example: increasing HIV in Lebanon |
| What is the difference between bright-field and light-field light microcopes? | Bright field emmits light on the whole specimen showing the whole structures, while dark field emits light only on the sides of the specimen (showing only the borders of the sample.) |
| What kind of microscopes do we use to see bacteria vs viruses? | Bacteria= light microscope, virus= dark microscope. |
| What kind of microscope do we use to observe spirochetes with small diameters? | Dark-field light microscope, since with light field the spirochetes wont appear due to their small diameter, light will pass right through it. |
| What disease is caused by treponema pallidum? | Sephilis. |
| What disease is caused by bacillus anthracis? | Anthrax which is used in bioterrorism, and causing organ failure, sepsis, inflammations, hemmorrhage and possibly death |
| What is meant by fluorescence? | Adding fluorochromes into something to color it
(for example: TB glowing yellow with fluorescence) |
| What are the two types of immunofluorescence? | Direct (antibody with fluorochrome attaches directly to the bacteria)
Indirect (antibody attaches to another secondary fluorescent antibody to color it) |
| Are introns present for bacterial genes? | For eubacteria yes, for archae they are abscent. |
| What are episomes found in bacteria? | They are non-chromosomal DNA molecules (plasmids) that may have a function in conferring against antibiotics |
| What are inclusion bodies found in bacteria? | Vacuoles with stored elements such as glycogen, poly-beta hydroxybuteric acid(PHB).. |
| What kinds of polyphosphate granules are found within bacteria? | Volutin (AKA metachromatin) |
| What are magnetosomes? | Collecting irons in bacteria |
| What is the mesosome? | It appears in the middle of the bacteria, its debated whether its an artifact during staining or has a role in binary fission |
| Do bacteria present sterols in their plasma membranes? | No sterols, instead they present hopanoids.
For archae, isoprenoids are present instead of sterols
For mycoplasma where no cell wall is present, sterols are present (the only exception) |
| Why do proteins in bacteria exist in larger amount than those of human cells plasma membranes? | Since bacteria live on their own, not inside an environment of an organ, so they need a lot of strength to survive --->increase in protein quantity. |
| What does exoenzymes mean? | They are enzymes secreted by bacteria and exerted outside where they apply their actions (for example cytotoxins that destroy other surrounding cells) |
| What does chemotaxis mean? | Movement induced by chemokines for bacteria) |
| What kind of passive diffusions usually occur for bacteria? | Simple and channel protein diffusions |
| What are sidophores? | They move iron from outside the bacteria |
| What is lactoferrin? | They are molecules that attract iron from milk, found mostly for babies in order to get iron for the body in opposed to magnetosomes of the flora. |
| What bacteria cannot be stained by gram staining? | Acid-fast bacteria, and mycoplasma (cannot be stained by any kind of staining since lacks cell wall) |
| What do we ask a px who we need a urine sample from to do? | Give us urine from midstream, since the upstream urine will be contaminated by flora from the skin, so in order to indentify whether we have a UTI, we need to exclude these flora and look for bacteria found inside the urinary tract.. |
| Describe the procedure of identifying gram + and -bacteria. | add crystal violet to sample - it will dye all bacterial cell walls purple.
add iodin- will fixate violet into only gram+ since they have a thich cell wall.
Add ethyl alcohol which will remove purple from gram-
add safarrin which will stain the unstained gram- pink |
| What do teichoic acids contribute to in bacteria? | Pathogenesis (they are virulence factors) |
| Difference between gram+ and - | . |
| Describe the molecules of the peptidoglycan layer. | N-acetyle glucasamine and N-a muramic acid attached to each other by beta (1-4) linkage
This linkage is destroyed by lysozymes, thus making gram + sensitive to it while gram - not (only 1 layer of peptidoglycans)
Tetrapeptide is attached to NAM sugar (alanine, glutamine, another aa, and DAP diaminopymelic acid which is precursor of lysin found only for bacteria) |
| Talk about teichoic acids in bacteria. | Found in gram+, present at cell wall and at membrane, give the structure of the cell wall (rigid) negatively charged. |
| What constitutes the gram- envelope? | Endotoxins
Lipoproteins
Lipopolysaccharides (three layers: Lipid A which is constant among bacterial species and causes immunopathology (sepsis)/ B = core saccharide which is the same for all gram -/ and C which is O antigen is unique for each species and important for stereotyping. |
| What external structures are found for bacteria? | Pilli (made of pillin protein, similar role to cilia, could be an adherence role like E.coli in urinary tract mediates attachment, pilli may by considered as virulence factors in the case of E.coli causing UTI, sex pilli cause conjugation role DNA exchange)
Flagella (Differ from euakryotic, made by protein flagellin, flagella has H-antigen) |
| What are the types of flagellated bacteria? | Atrichous (no flagella)
monotrichous (one flagella)
Lophotrichous (many flagella in one side)
Amphitrichous (one flagella on each side)
peritrichous (many flagella all over)
amphilotrichous (many flagella on two opposite poles) |
| Talk about capsule of bacteria. | Usually polysaccharides made, may be polypeptide (for bacillus anthracis)
Capsulated bacteria = have more protection.
capsules are tightly attached >> glycocalyx >> slime |
| What are biofilms? | combination of slime and calyx, making a middle sugar layer (for example plaques at teeth causing periodontitis) |
| Talk about bacterial porins. | Usually wide causing bacteriophages (viruses) to enter.
LamB porins transport sugars
Tsx porins transport nucleotides and amino acids
OmpA porins are recievers of sex pilus for conjugation (F-mediated) |
