Microbiology Exam 1

Chapters 1-9

Microbiology

The study of microorganisms

Bacteriology

The study of bacteria

Pathogen

Disease causing bacteria

Group: Protists

An informal group that aren’t plants, animals, or fungi.

Describe the ubiquity of microbes.

Microbes are found everywhere.

* 3:1 in humans
* most abundant cellular organism in the ocean (500mil/1L)
* 10bill per 1L of water in the ocean

Advantages of Microbes

* 70% of photosynthesis
* Decomposition
* Nutrient recycling

Disadvantages of Microbes

Disease

Characteristics of Viruses

* Acellular (non-living)
* Require host for metabolic activities
* Have hereditary material (dsDNA,ssDNA,ssRNA,dsRNA)
* Protein coat (capsid)
* may have an envelope
*

Characteristics of Prions

* Acellular (non-living)
* Misfolded proteins
* infectious (CJD, fatal familial insomnia)
*

3 Domains of Microbes

* Bacteria
* Archaea
* Eukaryotes

Characteristics of Bacteria and Archaea

* Single-celled
* w/o nucleus or other organelles
* 0.5-10μm

Characteristics of Eukaryotes

* Single-cellular or multi-cellular
* Contains a nucleus
* >10μm
* less abundant

Nomenclature

__Genus Species__

Taxonomy

the science of classifying living things into taxa.

Classification

a hierarchical arrangement of organisms.

Taxa in hierarchical Order

* domain
* kingdom
* phylum
* class
* order
* family
* genus
* species

Epidemology

the study of incidence distribution and control of disease.

Prevalance

the total number of individuals with a disease at a point in time.

incidence

the proportion of __new__ cases of a disease in a single specified time.

Noncommunicable disease

Doesn’t spread from person-2-person.

Communicable

able to spread from person to person.

Contagious

a communicable disease that spread easily.

Sporadic

Occur infrequently and irregularly.

Endemic

Constant in the region.

Epidemic

A large increase of cases in a specific region.

Pandemic

Worldwide epidemic.

Pure Culture

Single known species in a culture.

Mixed Culture

2+ known species in a culture.

Contaminated Culture

1 known culture & unknown contaminants in a culture.

Inoculation

Introduce a sample of microbes to a growth medium.

\-Goal: add microbes to a sterile growth medium.

Incubation

To grow microbial culture under suitable conditions.

\-Goal: to grow microbes under controlled conditions.

Isolation

To separate a specific species or strain from all others.

\-Goal: to obtain a colony of bacteria that grew from a single bacterium.

Inspection

Examine by macroscopic or microscopic appearance.

\-Goal: to identify colony size, shape, color, and texture on a __**macroscopic scale**__; and to identify cell size, shape, arrangement, and staining on a __**microscopic scale**__.

Identification

determine identity using biochemical, genetic, or immunological tests.

\-Goal: identify species or strain.

Liquid Broth Media

This media allows uniform growth.

Semi-solid Media

This media allows motility assays.

Solid/Liquid Broth

The media allows surface growth.

* 1%-5% agar
* 12% gelatin

General Purpose Media

This media allows broad spectrum growth.

Enriched Media

This media has complex substances added to it that’s required by certain fastidious species to grow.

Selective Media

This media inhibits growth of unwanted species.

Differential Media

This media causes a visual change when specific microbes grow on it.

Resolution

The power to distinguish 2 points from each other.

Contrast

Difference in light between image and background.

Working Distance

The distance between the tip of the objective lens and the specimen on the stage.

\-This distance decreases as magnification increases.

Field of View

The area that you can see through the lens.

\-This decreases as magnification increases.

\

Bright Field Microscopy

Dark Field Microscopy

Phase Contrast Microscopy

Fluorescence Microscopy

Confocal Microscopy

Transmission Electron Microscope (TEM)

Scanning Electron Microscope (SEM)

Light Microscopy

Use light to visualize images.

Brightfield Microscope

A compound microscope with 2+ lenses that produce a dark image on a bright background.

Darkfield Microscope

A compound microscope with 2+ lenses and a disk between the illuminator and condenser lens that produces a bright image on a dark background.

Phase Contrast Microscope

This microscope uses refraction and interference caused by structures in specimen to create a high contrast, high resolution image w/o staining.

Fluorescence Microscope

This microscope uses fluorescent chromophores (fluorochromes) that absorb energy from light sources and uses the energy to emit visible light.

Confocal Microscope

This microscope uses a laser to scan multiple Z-planes successfully that produces multiple 2-D, high resolution at various depths which can be constructed into a 3-D image.

Transmission Electron Microscope (TEM)

This microscope requires the specimen to be sectioned & stained with metal, then electrons are transmitted through specimen to visualize internal structures with high magnification and resolution.

Scanning lens

10x \* 4x = 40x

Low Power lense

10x \* 10x = 100x

High Dry Lens

10x \* 50x = 500x

Oil Immersion lens

10x \* 100x = 1,000x

Simple Staining

This type of staining uses a single dye that emphasizes particular structures in a sample.

Differential Staining

This type of staining distinguishes organisms based on their interactions with multiple stains.

Gram Stain

This staining method is used to distinguish between bacteria with different types of cell walls.

Endospore Stain

This staining method uses 2 stains to differentiate endospores from the rest of the cell.

Acid-Fast Stain

This method of staining is used to differentiate 2 types of gram (+) cell: those that have mycolic acids or not.

Gram Stain

Endospore Stain

Acid-Fast Stain

Coccus

Spheres

Bacillus

Rod-Shaped

\

Vibro

Curved rods (Mac&Cheese noodles)

Spirillum

Curled (loose coils)

Spirochete

Springy spiral

Branching filaments

Tree branches.

Cytoplasmic Membrane

* phospholipid bilayer
* selectively permeable
* regulates nutrients and waste products
* the site for metabolic reactions
* Found in only Gram (+)

Cell Wall

* provides structural support
* Made of peptidoglycan (thick, rigid/sturdy)
* found in both Gram (+) & Gram (-)

Cell Envelope

Surrounds the cytoplasm and protects the bacteria cell.

Outer Membrane

* has phospholipids and lipopolysaccharides(LPS)
* found only in Gram (-)

S Layer

* protein layer inside the glycocalyx
* in all archaea
* in bacteria found in hostile environments

Glycocalyx

* coat of polysaccharides
* Slime layer
* capsule

Cytoplasm

This internal structure is composed of mostly water and is considered a pool of nutrients and building materials.

Cytoskeleton

This internal structure contributes to cell shape and division.

Chromosomes

This internal structure contains the DNA for the cell

* bacteria have 1 circular
* eukaryotes have many and are rod shaped

Bacteria Ribosomes

30s = small subunit

50s = large subunit

70s = 30s+50s

Inclusion Bodies

This internal structure in prokaryotes are storage compartments.

Bacterial Endospores

This internal structure is produced by both Gram (+) and Gram (-) bacteria. It helps to resist extremes including:

* temperature
* radiation
* drying
* chemicals

Fimbriae

This external structure is found mostly in Gram (-) bacteria. Its hair-like and aid in attachment and colonization.

Pili

This external structure is a hollow tube used to connect with other bacterium to share plasmid DNA. It also assists in conjugation in Gram (-) bacteria, aids in attachment, and movement.

Nanotubes

This external structure is a tiny membrane extension that is capable of nutrient transfer between cells.

Flagella

This external structure aids in movement. This structure can have multiple arrangements and various modes of movement including:

* Run = rotating counterclockwise
* tumble=rotating clockwise
* Random walk = alternating between running and tumbling.

Chemotaxis

Cells moving in response to chemical signals. (more running than tumbling)

(+) chemotaxis

Cell moving towards a chemical signal (stimuli)

(-) Chemotaxis

cell moving away from chemical signal (repellant)

Nucleus

This internal organelle is surrounded by a complex membrane and houses the DNA genome. This organelle also, controls all cell activity.

Mitosis

This process is clonal reproduction for eukaryotes (IPPMAT)

Karyokinesis

Division of the nucleus. (PPMAT)

Cytokinesis

Separation of the cytoplasm.