Medical MicroBio Ch. 4

cell/cytoplasmic membrane

cell/cytoplasmic membrane

Thin sheet of lipids and proteins that controls what comes in and out

endospores

• Unmoving, resting, cells produced by gram positive genus (ex. clostridium)

• Hardiest of all life forms

• Dehydrated, inactive cells with thick coat, and almost immortal

• Resistant to ordinary cleaning products

• Have a two phase life cype called sporulation

sporulation

formation of endospores

• Vegetative cell

  • Metabolically active and growing

  • Are easier to treat with antibiotics and cleaning supplies

• Endospore

  • Occurs when exposed to adverse environmental conditions

  • Highly resistant and very long term survival

  • Able to withstand many environments and conditions

germination

return of an endospore to the vegetative growth state

types of bacterial shapes

• Coccus = spherical shaped

• Bacillus = Rod-shaped

• vibro = gently curved

• Filamentous

• Spirillum = Helical, comma, twisted rod

• spirochete = spring like

coccus

bacillus

vibrio

filamentous

spirillum

spirochete

bacterial arrangements

cocci:

• Singles

• Diplococci–in pairs

• Tetrads–groups of four

• Irregular clusters

• Chains

• Cubical packets (sarcina)

Bacilli:

• Diplobacilli

• Chains (Streptobacilli)

• Palisades- looks like a picket fence

phylogenic

• Classification of bacteria based on genetic information

• Includes archaea and bacteria, and 25 different phyla

phenetic

• Classification of bacteria based off cell wall structure, shape, arrangement, and physiological traits

rickettsias

• TINY, gram negative bacteria

• Pathogenic

• Obligate intracellular pathogens

• Cannot survive outside the host cell

chylamydias

• Tiny, obligate intracellular parasites

• Transmitted through skin to skin contact

• Chlamydia trachomatis = severe eye infection and one of the most common sexually transmitted diseases

• Chlamydia pneumoniae = lung infections

extremophiles

Live in the most extreme habitats in nature

methanogens

Methane producers

hyperthermophiles

Live in high temperatures

extreme halophiles

Requires high salty environment to grow

psychrophiles

Loving cold temperatures

Bacterial chromosome or nucleoid

A circular chromosome or nucleoid composed of condensed DNA molecules containing genetic information

ribosomes

• Tiny particles made of protein and RNA

  • Sites of protein synthesis

cytoplasm

Water-like solution filling the entire cell

S layer

Single layer or protein for protection or attachment

outer membrane

Extra membrane containing lipopolysaccharide

cell wall

Semirigid casing providing support and shape

actin cytoskeleton

Long fiber proteins contributing to shape of cell

plasmid

• Small double stranded DNA containing extra genes

  • Can be used for antibiotic resistance

flagella

• Rotate 360 degrees for motility

• 3 parts

  • Filament = long thin structure composed of protein

  • Hook = curved sheath

  • Basal body = stack of rings in cell wall

Monotrichous flagella arrangement

Single flagella at one end

Lophotrichous flagella arrangement

Small bunches emerging from the same site

Ampphilrichous flagella arrangement

flagella at both ends

Peritrichous flagella arrangement

Flagella all over surface

flagella response to stimuli

• Chemical stimuli

  • Chemotaxis = toward or awy from chemical concentrations

• Light stimuli

  • Phototaxis = toward or away from light

• Counterclockwise motion = smooth linear run

  • Clockwise motion = tumble

periplasmic flagella

• Internal flagella

• producing cellular motility by contracting and imparting twisting or flexing motions

fimbriae

Fine, hair-like bristles extending from the cell surface to help adhesion

pili

Rigid tube structure made of pilin protein

Type IV pili

only found in gram (-) cells ; have twitchlike movements

Conjugation pili

join bacterial cells for DNA transfer

glycocalyx

• Coating of molecules outside of the cell wall; made of sugars and/or protein

• Protect cells from dehydration and nutrient loss

• Phagocytize WBCs to help with causing disease

• Attaching cells can create biolfilms

• Types

  • Slime layer

    • Loosely organized and attached

  • Capsule

    • Highly organized, tightly attached

biofilms

• Cooperative associations among microbial groups

• Community of cells that evolves and undergoes specific adaptations for its habitat

• Quorum sensing

  • Individual species alters gene expression in cooperation with other cells in the biofilm

gram positive bacteria

• Thick cell wall composed of peptidoglycan and cell membrane

• retains crystal violet dye and appears purple

gram positive cell wall structure

• 20-80nm thick peptidoglycan layer

• Peptidoglycan layer contains teichoic and lipoteichoic acids to maintain wall, move cations, and stimulate immune response

  • May have a periplasmic space between the membrane and wall

gram negative bacteria

• Has an outercell membrane, thin pepdidoglycan, and cell membrane

• loses crystal violet dye and appears red from safranin

gram negative cell wall structure

• Has an inner membrane, outer membrane, and periplasmic space

• Has a thin peptidoglycan layer

  • Outer membrane has lipopolysaccharides (LPS) which can release toxins

peptidoglycan

• Primary component of cell walls

  • Alternating NAG and NAM glycan chains

gram stain

• Developed by a scientist named Gram who helped to differentiate between two different types of bacteria

• Differential stain distinguishing cells with a gram positive cell wall from cells with a gram negative cell wall

gram stain results

• When treated with ethanol Gram-positive-retain crystal violet and stain purple

• When treated with ethanol Gram-negative-lose crystal violet and stain red from safranin (reddish-pink) counterstain

Acid fast stain

Used to diagnose infections caused by bacteria without a typical cell wall structure

phylum proteobacteria

gram negative cell walls

phylum firmicutes

mainly gram positive with low G+C content

phylum actinobacteria

gram positive with high G+C content

rickettsia rickettisii

• Rocky mountain spotted fever; potentially fatal disease that's usually caused by the bite of a tick infected with rickettsia group bacteria.

rickettsia typhi

typhus