Module 2: Morphology of Bacteria Flashcards
Morphology
The study of shape/form of living organisms
Anatomy
The study of internal structure of organisms
2 classifications of microorganisms
Cellular (composed of one or more cells)
- Protists, Algae, Fungi, Archaea, Bacteria
Acellular (lacking cells)
- Viruses, viroids (small viruses composed only of RNA molecules), and prions (misfolded proteins that cause neighboring proteins to become misfolded)
6 Cell shapes
Coccus
Filamentous
Rod
Spirillum
Spirochete
Budding & Appendaged Microorganisms
Cell size and SA:V relationship
As cell size decreases, SA:V increases, increasing absorption
Plasmid
Extrachromosomal genetic material for phenotype characteristics
Phospholipid Make-up
- Composed of hydrophobic and hydrophilic components
- HYDROPHOBIC: TAIL, composed of fatty acids
-HYDROPHILIC: HEAD, composed of glycerophosphates
3 Functions of Cellular Membrane in Prokaryotes
- Permeability Barrier - prevents leakage; allows entrance and exit of nutrients; expels waste
- Protein Anchor - holds proteins responsible for transportation, bioenergetics (transformation of energy, often associated with ATP), and chemotaxis (movement associated with a concentration gradient)
- Energy Conservation - production of ATP
Differentiate GRAM POSITIVE and GRAM NEGATIVE bacteria
- Peptidoglycan thickness: Gram positive bacteria have thick peptidoglycan walls
- Outermost layers: Gram positive bacteria’s outermost layer is the peptidoglycan layer
- Appearance in gram-staining: Gram positive bacteria appears blue while gram negative bacteria appear red/green
Composition of Gram Positive Bacteria Wall
- Teichoic Acid
- Lipoteichoic Acid (lipid–> originates from phospholipid bilyaer)
- Wall-associated Proteins
Example of Coccus Bacteria
Streptococcus pneumoniae
Example of Rod Bacteria
Lactobacillus stearothermophilus
Example of Spirillum Bacteria
Vibrio Cholerae
Periplasm
Spaces between cell wall and cellular membrane of bacteria responsible for cell wall synthesis, more pronouncedly seen in gram negative bacteria
Lipopolysaccharides composition
and present in Gram ____ bacteria
(from outermost to innermost)
an O-specific polysaccharide,
the core polysaccharide,
KPO,
Lipid A
NEGATIVE
Peptidoglycan composition (GlcNAc) (MurNAc)
N-acetylglucosamine
N-acetylmuramic acid
Antigen is short for:
ANTIbody GENerating
Glycocalyx
2 types and differences
GLYCOCALYX - sugar “coat”; polysaccharide+projections
1. Capsule - attached tightly to the bacterium and has definite boundaries
2. Slime Layer - loosely associated with the bacterium and can be easily washed off
3 Functions of the Glycocalyx structures
- Assist in attachment to solid surfaces
- Virulence factors (cannot be easily detected if completely covered; immune system evasion)
- Prevent dehydration
Fimbriae
Thin, hairlike appendages, present on the cells of gram-negative bacteria; composed of proteins and some are composed of polysaccharides; allows bacteria to stick to surfaces (forming biofilms or pellicles)
Pili / Pilus (singular) + 4 functions
- Longer, more visible form of fimbriae
- receptors for certain viruses
- facilitates genetic exchange between cells
- adhesion to specific host tissues
- facilitates unusual cell movement (twitching motility)
4 Stage Process of Conjugation
- Donor bacterium extends pilus (as a bridge)
- The two microorganisms connect
- Replication of certain plasmid via DNA polymerase
- Separation of two microorganisms
3 Types of Genetic Exchange / Horizontal Gene Transfer
- Conjugation (sex pilus)
- Transformation (absorption of DNA from environment)
- Transduction (virus as the medium for genetic material exchange)
Cell Inclusions
Cell inclusions are considered various nutrients or pigments that can be found within the cell, but do not have activity like other organelles.
6 types of Cell Inclusions
- Carbon Storage Polymers
(Glycogen; poly-beta-hydroxybutyric acid; poly-beta-hydroxyalkanoate) - Polyphosphate Minerals
(for ATP, nucleic acids, phospholipid cell membrane) - Sulfur Minerals
(H2S in chemolithotrophy; proteins) - Carbonate Minerals
(biomineralization like barium strontium magnesium for anchorage) - Magnetosomes
(contains iron and aids bacteria orientation) - Gas Vesicles
(for buouyancy, and allows planktane cells to position themselves in regions best suited to their metabolic needs; impermeable to water and solutes but not to gases)
ENDOSPORES characteristics
- Resistant to heat, harsh chemicals, and reduction
- Survival structures
- Dormant stage of a bacterial life cycle
- Easily dispersed in wind water or through animal gut
- process of formation: ENDOSPORULATION / SPORULATION
Two types of endospore-forming bacteria
- Bacillus (aerobic)
- Clostridium (anaerobic)
6 Stages of Sporulation
- Asymmetric Cell Division; commitment to Sporulation
- Engulfment - mother cell engulfs spore forming 2nd membrane
- Cortex Formation - peptidoglycan layer protects spore from heat and harsh chemicals
- Spore Coat - outermost coat formed
- Maturation and Cell Lysis - when conditions stabilize, larger mother cell enters lysis
- Germination - spore loses spore characteristics returning to vegetative bacteria
4 types of Flagella Makeup
- Monotrichous
- Lopotrichous
- Amphitrichous
- Polytrichous/Peritrichous
-TRICHOUS
3 Types of Flagellum Movement
- Gliding
–> twitching mobility via extension-retraction of focal-adhesions complex; sex pilus and Type IV; produces slime (polysaccharides) - Swarming
–> multicellular movement over a surface caused by rotating flagella (surfactant present) - Swimming
–> individual cell movement in a liquid environment
2 Archaea Specific Structures
- Archaeal Cell Wall
- Pseudomurein
- Thick Polysaccharide
- S-Layer - Hamus
- unique attachment structure of Archaea that resembles a grappling hook
- SM1 group (specifically)
- for movement & to secure itself in oxygen-absent environments
3 Microbial Eukaryotes
- Fungi
- Algae
- Protists
Hydrogenosome
- Mitochondrion stand-in for anaerobic lifestyles
- Strictly for fermentative metabolism
- Lacks citric acid cycle enzymes
- Lacks cristae
- Oxidizes pyruvate to H2, CO2, and acetate
3 Acellular Particles
- Prions (and Nonpathogenic Prions)
- Subviral agent (viroids)
- Viruses
Capsid
Protein coat of viruses
Nucleocapsids
Protein coat of viruses that surround nucleic acids
Viroids description
- infectious RNA molecules - smallest known pathogens
- lacks protein component
- small circular single-stranded CLOSED RNA molecules
- only found in plants
- does not cause diseases in microorganisms of animals
- RNA polymerase replicates viroids in plants
Prions description
- infectious agent composed entirely of proteins
- causes several neurological diseases (mad cow disease, scrapie, variant creutzfeldt)
- catalyze protein conformational changes
- not seen in plants, but seen in yeast
3 Stages of Prion Infectious Cycle
- Prion protein cellular undergoes nucleation to produce prion protein scrappy (which is the infectious agent)
- Prion protein scrappy undergoes elongation and conformational change to become an AMYLOID (leads to multiple diseases)
- Amyloids breaks down into multiple new “seeds” or prion protein scrappy to repeat the process
Nonpathogenic prions description
- Proteins that adapt fungal cell walls to survive dynamic environmental conditions
- [URE3] prion can increase number of nitrogen-metabolizing proteins in the cell membrane
- MAVS protein in humans can trigger production of INTERFERONS
Pseudomurein composition (where is the glycosidic bond between molecules, what kind of stereoisomer?)
- GlcNAc (N-acetylgulcosamine)
- N-acetyltalosaminuronic acid
- Glycosidic bonds between sugar derivitives is beta-1,3 (rather than beta-1,4)
- Amino acids are all L stereoisomer
Pseudomurein composition (where is the glycosidic bonds and what kind of stereoisomer)
- GlcNAc (N-acetylgulcosamine)
- N-acetyltalosaminuronic acid
- Glycosidic bonds between sugar derivitives is beta-1,3 (rather than beta-1,4)
- Amino acids are all L stereoisomer
Thick Polysaccharide composition (3G 1A)
- Glucose
- Gluconic Acid
- Galactosamine uronic acid
- Acetate
S-Layer composition (paracrystalline surface layer) and 3 functions
- interlocking protein or glycoprotein
- forms various symmetries
- strong to withstand osmotic pressures without any other cell wall components
- selective sieve
- retains proteins
Define Virion
the complete, infective form of a virus outside a host cell, with a core of RNA or DNA and a capsid.
