Unit 1
What was the main goal of Louis Pasteur’s swan-neck flask experiment?
Its main goal was to disprove spontaneous generation. The curved neck let air in but trapped dust/microbes at the bend, so broth stayed sterile unless the flask was tilted to let contaminants reach it — proving microbial growth comes from existing microbes in the environment, not spontaneous generation.
These microbial proteins bind to specific receptors on host cells to allow attachment.
Adhesins — microbial surface proteins that bind specific host-cell receptors to enable attachment.
There are 2 types of these microscopes, one provides a 3D image of the surface of a specimen and the other shows internal cell structures using thin sections of a specimen.
Where is the ATP synthase located in the prokaryotic cell in comparison to the eukaryotic cell?
This type of medium allows bacterial movement and observation of growth rate changes.
liquid media
What is the Germ Theory of Disease and which scientists confirming this theory?
The theory that specific diseases are caused by specific microorganisms invading the body. Building on Pasteur's work, Robert Koch confirmed it through his postulates (a set of criteria linking a specific microbe to a specific disease).
After an acute infection, this type of infection remains in the body without symptoms, such as herpes causing cold sores.
Latent infection — pathogen remains dormant in the body without symptoms after the acute phase (e.g., herpes simplex virus causing recurring cold sores).
What is the difference between a spirillum and a spirochete?
How do eukaryotic flagella move in comparison to prokaryotic flagella?
This technique uses an inoculating loop to separate individual cells on an agar plate.
dilution streaking
Define bioremediation.
The use of microorganisms (or their enzymes) to degrade, neutralize, or remove pollutants and contaminants from a contaminated environment (soil, water, etc.).
Define LD50 and ID50.
This interaction of light is especially important in dark-field microscopy.
Light scattering — light bouncing off the specimen at angles; essential to dark-field microscopy, which uses only scattered light to illuminate the specimen against a dark background.
This type of movement allows spirochetes to move through viscous environments:
corkscrew motility
Media designed for organisms with demanding nutritional requirements are called this.
enriched media
Name the three functions of microbes.
Fix nitrogen into forms used by plants, produce vitamins, primary producers
Define the difference between a focal infection, disseminated infection, and metastatic infection.
focal infection: initial site of infection from which the organism can travel via the bloodstream to another area: boils
Disseminated infection: Infection caused by organisms traveling from a focal infection, affecting several organ systems
Metastatic infection: site of infection resulting from dissemination
Total magnification is calculated using this formula.
Total magnification = Ocular lens magnification × Objective lens magnification
What are the structures outside the cell wall, and describe each of them (there are 4!) and explain lipid A
Capsules– organized –protection from our immune action
Slime layers– unorganized
Glycocalyx– Functions include attachment to surfaces (including host tissues), protection, and cell-to-cell communication. It exists in two forms: capsules and slime layers.
S-layers– ion + pH fluctuations
Lipid A — The lipid anchor of LPS in the outer membrane of gram-negative bacteria; it's released upon cell lysis and acts as an endotoxin, triggering fever, inflammation, and potentially septic shock.
Name the stages of bacterial growth and describe each stage.
Which scientist was responsible for
1) creating the first mass vaccine
2) using antiseptics
3) chemical treatments of surgical instruments (aseptic technique)
1) Edward Jenner
2) Ignaz Semmelweis
3) Jospeh LIster
Name the stages of infectious disease and at what stage are symptoms most severe?
Incubation → Prodromal → Illness (acme) → Decline → Convalescence. Symptoms are most severe during the illness (acme) period.
Differentiate between acid-fast staining, endospore staining, and acidic dyes.
Eukaryotic flagella and cilia have this microtubule arrangement.
9+2 arrangement
Name the difference between auxotroph and fastidious organisms.
Auxotrophs: mutants that lose the ability to synthesize growth factors
Fastidious: complex nutritional requirements and need specific growth factors