Microbiology Final (Eric Shows Jones College)

Microbiology is the study of

microbes related to their molecular and cellular anatomy, physiology, genetics, and their ecology

ecology

the study of how organisms interact with their environment

mikros (Greek)

Small

bios (Greek)

life

logos (Greek)

discourse, study, reason

microbes include

bacteria & archaea

viruses

fungi

protozoa

Helminths

algae

how does microbiology intersect with other disciplines?

Virology (virus)

Bacteriology (bacteria)

Mycology (fungus)

Parasitology (parasites)

Immunology (Immune system)

Serology (blood serum)

because of the connection to infectious disease, microbiology is unavoidably linked to ________________.

epidemiology (the study of incidence, distribution, causes, and control of diseases.)

___________contains specific antibodies against a particular microbe.

antiserum

functions of a microbe

decomposition

nitrogen fixation

photosynthesis

symbioses

ubiquitous

present or existing everywhere

Shigella

a microbe that causes bacillary dysentery (infection of the intestines resulting in severe diarrhea with the presence of blood and mucus in the feces) with only being exposed to very few cells

Microbiome

the microorganisms in a particular environment

pathogenic microbe

microbe that has the capacity to produce disease

true pathogens

exists in order to reproduce and infect

opportunistic pathogens

causes disease if the situation is perfect

Virulence

how easily the pathogen can infect and cause a disease in a host

avirulant

Incapable of causing disease

Virulance factors

invasiveness (the ability of a microbe to establish itself in/on a host)

toxigenicity (the ability for the microbe to produce a toxin in order to weaken/damage a host

Taxonomy

the system of assigning formal scientific names and classifications to organisms

phylogeny

The study of evolutionary relationships among organisms

Taxonomy classification system

three domains of life

Bacteria, Archaea, Eukarya

Metabolically diverse, found in most any habitat; prokaryotic; typically unicellular. (domain of life)

Bacteria

extremeophiles; prokaryotic; typically unicellular (domain of life)

Archaea

-philes

favor, attracted to, like

Eukaryotic; contain a membrane-bound nucleus; can be multicellular or unicellular (domain of life)

Eukarya

binomial nomenclature

A system for giving each organism a two-word scientific name that consists of the genus name followed by the species name

True or False:

prokaryotic cells don't have a plasma membrane

False; both prokaryotic and eukaryotic cells have a plasma membrane called the phospholipid bilayer

what is the cell wall of a prokaryotic cell made from?

peptidoglycan (bacteria);polysaccharides and/or proteins (archea)

some prokaryotic cells have an external layer to the cell wall. what is the name of this layer?

glycocalyx

structures of motility in prokaryotic cells

flagella

prokaryotic cells genetic material location

nucleoid region

eukaryotic cells genetic material location

nucleus, mitochondria, and chloroplasts

meter (m)

measures distance

liter (L)

measures volume

gram (g)

measures mass

kilo-

k

10³

centi-

c

10^-2

milli-

m

10^-3

micro-

10^-6

nano-

10^-9

prokaryotic and eukaryotic cells are measured in...

micrometers

viruses are measured in...

nanometers

structures of movement in eukaryotic cells

flagella, cilia, pseudopodia

parts of a prokaryotic flagellum

Filament: the tail; made of a protein called flagellin

Hook: anchor which is embedded into basal body

Basal Body: rings that are anchored through the cell wall, periplasmic space, and cell membrane

what movement do bacterial flagellum make for motility?

rotating movement due to ions

what movement do eukaryotic flagella make for motility?

whip like motion powered by ATP proteins.

prokaryotic flagellum: filament

helical structure composed of a protein called flagellin. This forms the protruding tail of the flagellum.

prokaryotic flagellum: hook (sheath)

curved tubular structure anchored to the cell by the basal body

prokaryotic flagellum: basal body

stack of rings fixed to hold the flagellum together. It is attached firmly through the cell wall, periplasmic space, and the cell membrane

Polar flagellation

having flagella coming from one or both ends of the cell of the prokaryotic cell

monotrichous flagella

single flagellum attached at one end of the cell

lophotrichous flagella

more than one flagella at one end of the cell

amphitrichous flagella

flagella at both poles of the cell

peritrichous flagella

flagella that cover the surface of a cell

endoflagella

flagella that spiral tightly around a cell instead of protruding

taxis

movement in response to an environmental stimulus

+ taxis

movement toward the stimulus

- taxis

movement away from stimulus

chemotaxis

Cell movement that occurs in response to chemical stimulus (food source)

movement in response to sunlight

phototaxis

movement in response to Oxygen gradients

aerotaxis

magnetotaxis

movement toward or away from the Earth's magnetic field

what are the two types of pili called

fimbriae

sex pili

What are fimbriae?

hairlike appendages that allow for attachment

What are sex pili?

only found in G- bacteria; involved in connecting cells during bacterial conjugation (a type of horizontal gene transfer)

what are hamus

grappling hook like structures that are used to aid in cell-to-surface attachment.

what is the purpose for the bacterial glycocalyx

protection; helps to adhere to surfaces (increases virulance); can also help form biofilms

What is a biofilm?

protective aggregates of microbes that form on surfaces such as teeth, gums, implanted medical devices, industrial piping, and terrestrial and aquatic habitats

what are the two types of glycocalyxes and their structure?

slime layer; loose

Capsule; organized

glycocalyces: slime layer

a loose layer that protects the bacterium from dehydration and nutrient loss

composed of polysaccharides, protein, and/or glycoproteins

gives the cell wall a sticky consistency

glycocalyces: capsules

a thicker, more organized layer

composed of polysaccharides, proteins, and/or glycoproteins

the layer is chemically bonded to the cell

cell wall

cell membrane

periplasmic space

what are the parts of the bacterial cell envelope

periplasmic space

internal space between the plasma membrane and the cell wall

what is the purpose of the cell wall

to protect and support the cell; also helps prevent osmotically-induced lysis.

peptidoglycan

A type of polymer in bacterial cell walls consisting of glycan (polysaccharide) that are cross linked by peptides (amino acid chains)

what are the steps to the gram stain

crystal violet

rinse

iodine

rinse

alcohol

rinse

safranin

rinse

in microscopy, how can you determine if the cell is gram positive or gram negative

Purple cell = gram positive

Pink cell = gram negative

what are characteristics of a gram positive cell

the thick peptidoglycan layer of the cell wall

teichoic acid

lipoteichoic acid

what type of electrical charge does the gram positive cell wall have

negative charge

what are the obvious characteristics of a gram negative cell wall?

a thin peptidoglycan layer plus an extra outer membrane

how is the extra outer membrane of a gram negative cell wall anchored

braun's lipoproteins

what are the exceptions to a gram staining result and why are they exceptions

Mycobacterium and Nocardia spp.; they have mycolic acid

Myoplasma spp.; naturally lack a cell wall

L forms; parts of the cell wall have holes

1. bacteria can lose their cell wall forming genes

2. bacteria is exposed to penicillin

3. bacteria are exposed to an antimicrobial enzyme

why would a cell lose it's cell wall

what are the two types of L forms and where are they found

Protoplast; G+ bacteria

Spheroplast; G- bacteria

Protoplast

an osmotically fragile round body that results from G+ bacteria losing their cell walls

the outermost covering will now be the plasma membrane

Spheroplast

an osmotically fragile round body that results from G- bacteria losing their thin peptidoglycan layer but retaining the outer membrane of their cell wall

True or False; all cells have a cell membrane

True

what are the functions of a prokaryotic cell membrane

1. controls what enters and leaves the cell

2. allows for secretion

3. contains enzymes for making structual macromolecules

4. contains infoldings studded with enzymes

5. contains receptors for taxis

cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

cytosol

Fluid portion of cytoplasm

What is the nucleoid region?

Region in prokaryotic cells where DNA is located (in cytoplasm)

What are plasmids?

Plasmids are small loops of extra DNA that aren't part of the chromosome. Plasmids contain genes for things like drug resistance and can be passed between bacteria.

What are ribosomes?

site of protein production

inclusions

aggregations of organic and inorganic material in the cell

may or may not be membrane enclosed

type of inclusions: metachromatic granules (volutin)

aggregates of poly- and metaphosphates that act as a phosphate reservoir for metabolic reactions

Corynebacterium spp. often contain these granules.

type of inclusions: magnetosomes

granules composed of magnetite that are used by some bacterial species to orient themselves relative to the Earth's magnetic field

type of inclusions: Glycogen and PHB inclusions

carbon storage

type of inclusions: gas vesicles

controlled to provide buoyancy