Unit 2: Bacteriology Flashcards by Charmaine Pascua

The average diameter of spherical bacteria is _____ µm.

For rod-shaped or filamentous bacteria, length is _____ µm and diameter
is _____ µm.

Diameter 0.5-2.0

Length 1-10
Diameter 0.25-1.0

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Cell morphology According to SHAPE

• Coccus
• Rod/bacillus
• Spirilla

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_____– spherical or ovoid shape

_____ – cylindrically shaped cell

_____– spiral shapes

Coccus

Rod/bacillus

Spirilla

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causes Pneumonia

Streptococcus pneumoniae

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causes armpit to stink

Micrococcus luteus

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can cause sinus infections and food poisoning

Staphylococcus aureus

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Sphere shaped (_____)
Rod shaped (_____)
Spiral shaped (_____)

cocci
bacilli
spirochetes

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can cause stomach ulcers

Helicobacter pylori

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According to ARRANGEMENT:

• Monococcus
• Diplococcus/bacilli
• Streptococcus/bacilli
• Staphylococcus
• Sarcina
• Tetrad
• Coccobacillus

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• _____ – singular cocci
• _____ – two spherical/rod arranged in pairs
• _____– cocci/bacilli form in long chains
• _____– grapelike clusters
• _____– three-dimensional
cubes (consist of eight cells)
• _____– arranged in a group of 4 cocci cells.
• _____– short round rod

Monococcus
Diplococcus/bacilli
Streptococcus/bacilli
Staphylococcus
Sarcina
Tetrad
Coccobacillus

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Unusual shapes:

• Vibrio
• Spirochetes
• Appendaged bacteria
• Star-shaped bacteria (Stella)
• Square shape (Haloarcula)

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• _____ – curved rod
• _____– tightly coiled bacteria
• _____ – possess extensions of cells as long tubes or stalks
• Star-shaped bacteria (_____)
• Square shape (_____)

• Vibrio
• Spirochetes
• Appendaged bacteria
• Star-shaped bacteria (Stella)
• Square shape (Haloarcula)

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Fine, hairlike bristles extending from the cell surface that help in adhesion to other cells and surfaces.

Fimbriae

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Specialized appendage attached to the cell by a basal body that holds a long, rotating filament. The movement pushes the cell forward and provides motility.

Flagellum

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Structures common
to all bacterial cells

Cell membrane
Cytoplasm
Ribosomes
One (or a few) chromosomes

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Structures found in
most bacterial cells

Cell wall
Surface coating/glycocalyx

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Structures found in
some bacterial cells

Flagella
Pili
Fimbriae
Capsules
Slime layers
Inclusions
Actin cytoskeleton
Endospores

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specialized structure of bacteria

Endospore

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causes Thypoid

Salmonella enterica

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• Gelatinous solution
• Site for many biochemical
and synthetic activities
• Location of growth,
metabolism, and replication

Cytoplasm

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• Surrounds the cytoplasm and separates it from the
environment

• Function as a SELECTIVE PERMEABILITY

Plasma membrane

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Plasma membrane

• Consists of glycerol group (hydrophilic head) and
fatty acids (hydrophobic tail) by _____ linkage

ESTER Linkage

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A variety of proteins are attached to or
integrated into the cytoplasmic membrane:

INTEGRAL MEMBRANE PROTEINS

PERIPHERAL MEMBRANE PROTEINS

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______embedded in the membrane
______more loosely attached

INTEGRAL MEMBRANE PROTEINS

PERIPHERAL MEMBRANE PROTEINS

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_____ Important Properties • ability to regulate transport across cellular boundaries • permeable to specific ions and a variety of polar molecules

Plasma membrane

Archaeal membranes Consists of the glycerol group and isoprene (hydrophobic side chain) by_____ bonds

ETHER

_____ – resistant to heat

lipid monolayer

Functions of the plasma membrane

Permeability barrier Protein anchor Energy conservation

• Withstand pressure • Protection against osmotic lysis • Confer shape and rigidity

Cell wall

Thick Peptidoglycan = Gram-positive Thin Peptidoglycan = Gram-negative

Act as antibiotics

Lysozyme

Peptidoglycan structure NAG B1-4 NAM

N-acetylglucosamine B1-4 N-acetylmuramic acid

A protein that cleaves β-1,4- glycosidic bonds in peptidoglycan

Lysozyme

Composed of 90% peptidoglycan

Gram-positive cell wall

Types of Gram-positive cell wall

TEICHOIC ACID LIPOTEICHOIC ACID

______: acidic molecules embedded in the cell wall • Covalently bonded to muramic acid in the peptidoglycan ______: certain teichoic acids covalently bound to membrane lipids

TEICHOIC ACID LIPOTEICHOIC ACID

• Outer membrane • Consist of Lipopolysaccharide (LPS) and Thin peptidoglycan • Consist of Lipopolysaccharide (LPS) as endotoxin

Gram-negative cell wall

major strengthening agent

Peptidoglycan

acts as an effective barrier against many lipophilic antibiotics and other harmful agents that might otherwise penetrate the cytoplasmic membrane.

Gram-negative cell wall

are molecules that elicit strong immune response.

Endotoxins (LPSs)

• Composition: Endotoxins are lipopolysaccharides, while exotoxins are soluble proteins that can act as enzymes. • Source: Both Gram-negative and Gram-positive bacteria produce exotoxins, but only Gram-negative bacteria produce endotoxins. • Enzymatic Activity: Endotoxins cannot act as enzymes, while exotoxins can. • Location: Endotoxins are part of the outer membrane of Gram-negative bacteria, whereas exotoxins are secreted extracellularly. • Toxicity: Exotoxins are more toxic than endotoxins. • Specificity: Exotoxins are strain-specific, while endotoxins are not. • Heat Stability: Exotoxins are not heat stable, but endotoxins are. • Antigenicity: Exotoxins are highly antigenic, while endotoxins are poor antigens. • Immune Response: Exotoxins stimulate the immune system to produce antitoxins, whereas endotoxins do not.

a polysaccharide similar to peptidoglycan

PSEUDOMUREIN

Contain PSEUDOMUREIN: a polysaccharide similar to peptidoglycan

Archaeal cell wall

The most common type of cell wall in Archaea

paracrystalline surface layer/ S-layer

S-layers can form various symmetries

hexagonal, tetragonal, or trimeric

sufficiently strong to withstand osmotic

S-layer

Application Gram staining ______ - primary stain ______ - mordant ______ - decolorizer ______ - counter stain

Crystal Violet Iodine 95% Ethyl Alcohol Safranin

an insoluble, colored compound that forms when crystal violet (CV) interacts with iodine (I)

crystal violet-iodine complex

______ = “sugar coat” Extracellular, made up generally of polysaccharide, polypeptide or combination of both (glycoprotein)

Glycocalyx

Protects pathogenic species from phagocytosis by macrophages

Glycocalyx

Types of glycocalyx

Capsule and Slime Layer

Types of Glycocalyx ______: ADHERE FIRMLY to the cell wall ______: LOOSELY ATTACHED to the cell wall

CAPSULE SLIME LAYER

Tiny rotating machines that function to push or pull the cell through a liquid

Flagella

Fleagella 1._____ protein found in the filament of a bacterial flagellum 2. _____ a wider region at the base of the filament 3. ______ anchored in the CM (cytoplasmic membrane) and cell wall; consists of a central rod that passes through a series of rings: • _____ an OUTER RING, anchored in the LPS layer in gram-negative bacteria • ______: SECOND RING, anchored in the peptidoglycan layer of the cell wall • ______ & ______ located within the CM and the cytoplasm, respectively.

Flagellin Hook Flagellum motor - L ring - p ring - MS ring and C ring

Flagella _____ surrounding the inner rings to generate torque.

Mot proteins

Flagella _____ function as the motor switch

Fli proteins

Flagella _____ energy required for the flagellar rotation

Proton Motive Force

Flagellar arrangement

Peritrichous Monotrichous Lophotrichous Amphitrichous

Flagellar arrangement _____ flagella are inserted at many locations around the cell surface. _____ a single polar flagellum at one end or the other _____ a group of flagella (tuft) may arise at one end of the cell. _____ a tuft of flagella emerges from both poles of the cell.

Peritrichous Monotrichous Lophotrichous Amphitrichous

capable of both clockwise and counterclockwise rotation

rotating type IV pilus

Rotation of the archaellum is driven by the hydrolysis of ATP

Function: adhesion to host cell or surface of substrate

Fimbriae

Fimbriae •______ : chemical components of bacterial glycocalyx, cell walls, pili • ______: usually glycoproteins located on cell membrane or tissue surface or fimbriae

Adhesins Host’s receptors

 longer than fimbriae  RECEPTORS for certain types of viruses  facilitates genetic exchange (CONJUGATION)  Mediate genetic transfer (TRANSFORMATION)  enabling ADHESION of pathogens to specific host tissues

Pili

support cell movement called twitching motility type of gliding motility: movement along a solid surface

Type IV pili

What do u call the cell movement

Twitching motility

What do u call the cell movement

Twitching motility

Inclusion Bodies: Energy reserves CARBON STORAGE POLYMERS

Poly-β-hydroxybutyrate (PHB) Poly-β-hydroxyalkanoate (PHA) Glycogen

most common carbon-based inclusion bodies in prokaryotic organisms; a lipid that is formed from β-hydroxybutyric acid units.

Poly-β-hydroxybutyrate (PHB)

carbon- and energy-storage polymers

Poly-β-hydroxyalkanoate (PHA)

inorganic phosphate accumulation forming granules.

Polyphosphate

degraded and used as sources of phosphate for nucleic acid and phospholipid biosynthesis

Polyphosphate

elemental sulfur that accumulates inside the cell when hydrogen sulfide is oxidized.

Sulfur globules

form inside the cell of some cyanobacteria

Carbonate minerals

Carbonate minerals • ______ : forms benstonite that contains barium, strontium, and magnesium • ______ : microbiological process of forming minerals

Gleomargarita Biomineralization

process of migrating along Earth’s magnetic field lines

Magnetotaxis

Enclosed by a thin membrane: • functional as they catalyze iron precipitation during magnetosome synthesis.

Magnetosome

Cyanobacteria and algae form massive accumulations called _____ in lakes or other bodies of water.

blooms

Inclusion bodies: _____ highly differentiated cells that are extremely resistant to heat, harsh chemicals and radiation.

Endospore

• Functions: survival structures, to endure unfavorable growth conditions.

Endospore

Dormant stage of a bacterial life cycle: vegetative cell – endospore – vegetative cell

used to stain endospore

Malachite green

Inclusion Bodies: Endospore parts

Exosporium Spore coats Cortex Core

Endospore parts • ______: a thin protein covering on the outermost layer of the endospore. • ______: composed of spore- specific proteins (second layer). • ______: next to spore coat which consists of loosely cross-liked peptidoglycan. • ______: inside the cortex, which contains the core wall, CM, cytoplasm, nucleoid, ribosomes and other cellular essentials.

Exosporium Spore coats Cortex Core

Ribosomes Two subunits:  smaller subunit (SSU) binds to mRNA  larger subunit (LSU) binds to the tRNA and the amino acids.

Prokaryotes= 70S ribosomes • 50S (LSU)– has 23S RNA (2900 nucleotides), 5S RNA (120 nucleotides) and 34 proteins • 30S (SSU)– has 16S RNA (1540 nucleotides) bound to 21 proteins

Eukaryotes= 80S ribosomes • 60S (LSU)– has 28S RNA (4700 nucleotides), 5.8S RNA (160 nucleotides), 5S rRNA (120 nucleotides), and 46 proteins • 40S (SSU)– has 18S RNA (1900 nucleotides and 33 proteins

Essential functions of genetic material

replication and expression

contained in a single circular molecule =

Bacterial chromosome”

irregular shape of chromosomes

Nucleoid

Prokaryotes Shape: circular Extrachromosomal: plasmids Number of gene in chromosomes: one

Eukaryotes Shape: linear Extrachromosomal: absent Number of gene in chromosomes: two

______: extrachromosomal units

PLASMIDS

Plasmid Structure: ______ represents where nucleotide sequence begins

Ori

Plasmid Structure: ______ indicates gene of interest to identify for selection of the plasmid

Antibiotic resistance

Plasmid Structure: ______ represents the cloning sites, or a small piece of DNA into which a foreign DNA fragment can be inserted in cloning

Polylinker