Chapter 7 Flashcards
Longest known bacterium
Epulopiscium
Calcifying nanoparticles
Nanobacteria
Shapes of a prokaryotic cell
Cocci Bacilli vibrios spirilla spirochaetes
What is an example of fruiting bacteria?
Myxobacter
What is an example of a stalked bacteria?
Caulobacter
What is an example of a budding bacteria?
Hyphomicrobium
What are examples of filamentous bacteria?
- cyanobacteria
- actinomycetes
What is an example of a wall-less pleomorphic prokaryote?
Mycoplasma
What is an example of an pleomorphic prokaryote?
Rhizobium
Example of a fusiform/ spindle-shaped and filamentous prokaryote
Fusobacterium
Arrangement of prokaryotic cells
1 plane
- Diplococcus - 2 cells
- Streptococcus - variable number of cells in a chain
2 planes
- Tetrad - 4 cells
- Sarcina - packet of 8-64 cells
Several planes
-Staphylococcus and Micrococcus - irregular clusters
Carbon source and energy source of
- Photoautotrophs,
- Photoheterotrophs,
- Chemoautotrophs,
- Chemoheterotrophs
- CO2 , Sunlight
- organic materials , sunlight
- CO2 , organic materials
- organic materials , organic materials
Nitrogen-fixing bacteria
Rhizobium
Plant pathogen
Agrobacterium
A gelatinous polymer (network of polysaccharides) extending from the surface of bacteria to other cells
Glycocalyx
Importance of glycocalyx.
Protection against
- ion and pH changes and osmotic stress
- certain enzymes
- predacious bacteria and phagocytes
Enhances virulence of pathogenic bacteria
TYPES of glycocalyx
Capsule
Slime layer
S layer
Well-organized and not easily washed off
Capsule
Unorganized, diffused and easily removed
Slime layer
Bacteria in dental plaque
Biofilm
Proteins or glycoproteins that are regularly structured
S layer
Difference of gram negative and gram positive archaea and bacteria
In gram positive, may peptidoglycan after S layer
Thread like locomotor appendages
Flagella
3 parts of flagella and describe
Filament - longest portion
Hook - short curved segment which links filament to the basal body
Basal body - embedded in the cell
Pattern of arrangement of flagella
Monotrichous - 1 flagellum(polar)
Amphitrichous - 1 flagellum at each pole
Lophotrichous - cluster of flagella at one or both ends
Petritrichous - flagella spread all over the whole bacteria
Short, fine hair like appendages in many gram-bacteria; 1000/cell; aids in attachment
Fimbriae
1-10 per cell; required for bacterial mating
Pili
Gives bacteria shape and rigidity; contributes to the pathogenicity of pathogenic bacteria; protects bacteria from harmful substances; site of action of some antibiotics
Cell wall
4 divisions of prokaryotes
Gracilicutes
Firmicutes
Tenericutes
Mendosicutes
Thin cell walls, gram-negative type cell wall
Gracilicutes
Division of class Cyanobacteria and non-PStic bacteria and anaerobic PStic bacteria
Gracilicutes
Thick and strong skin, gram-positive type cell wall
Firmicutes
Division of class Rods and cocci, Actinomycetes and related organisms
Firmicutes
Pliable and soft natured cell wall, indicating the lack of a rigid cell wall.
Tenericutes
Division of class Mycoplasmas
Tenericutes
With unusual cell wall (lack conventional peptidoglycan)
Mendosicutes
Division of class Archaea
Mendosicutes
A polymer of disaccharides linked by polypeptides
Peptidoglycan or murein or mucopeptide
Carbohydrate backbone of peptidoglycan of bacterial cell wall
N-acetylglucosamine(NAG)
N-acetylmuramic acid (NAM)
Gram positive bacterial cell wall:
Thick PG
With TA
Without OM
Gram negative bacterial cell wall:
Thin PG
Without TA
With OM
–
Components of outer membrane in cell wall of bacteria
Lipopolysaccharides
Lipoproteins
Phospholipids
Short polysaccharide extending outward from the core. Acts as antigen; distinguishes between species by serological methods
O side chain or O antigen
3 components of lipopolysaccharide
O side chain
Core polysaccharide
Lipid A
Lipid component found buried within the outer membrane
Lipid A
Lipid component composed of sugars
Core polysaccharide
Importance of lipopolysaccharides
- imparts a strong negative charge
- Stabilization of membrane structure
- acts as endotoxin due to lipid A (causes fever and shock)
- protective barrier (prevents entry of bile salts, antibiotics and other toxic substances
Lack cell walls; sterols in plasma membrane; macrolides
Mycoplasmas
Atypical cell wall
Cell wall of archaea
Cell wall lacking muramic acid and D-amino acids; resistant to lysozyme and B-lactam antibiotics
Cell wall of archaea
Cell wall stain with a single thick homogenous layer
Gram positive archaea cell wall
Cell wall stain which lacks the outer membrane and complex peptidoglycan network with a surface layer of protein or glycoprotein subunits
Gram negative archaea cell wall
Some gram positive archaea cell walls have:
Pseudomurein, complex polysaccharides, and heteropolysaccharides
Polymer that has L-amino acids, N-acetyltalosaminuric acid instead of NAM, B-1,3 glycosidic bonds
Pseudomurein
Component of archaea cell wall which is highly organized, asymmetric, flexible and dynamic; contains lipids and proteins
Cell membrane or plasma membrane
Membrane proteins loosely associated with the membrane and easily removed
Peripheral proteins
Membrane proteins embedded within the membrane and not easily removed.
Integral proteins
Functions of cell membrane:
- separation of cell from environment
- selectively permeable barrier
- site of crucial metabolic processes
- detection of chemicals in surroundings with aid of special receptor molecules in the membrane
Invaginations of the plasma membrane
Mesosomes
Mesosomes are more prominent in: (gram stain)
Gram positive
Mesosome may be involved in:
Cell wall formation
Chromosome replication and distribution to daughter cells
Secretory processes
What links straight chain fatty acids, membrane lipids?
Ester-linked
Sterol-like molecules which stabilize the bacterial membrane.
Hopanoids
What links membrane lipids of cell membrane of archaea, which are branched chains of hydrocarbons attached to glycerol?
Ether-linked
Lacks unit membrane-bound organelles; largely water
Cytoplasmic matrix
Granules of organic or inorganic materials
Inclusion bodies
Organic materials in prokaryotes
Glycogen/ starch granules Poly-B-hydroxybutyrate Cyanophycin Carboxysomes BT crystal protein Gas vacuoles
Inorganic materials in prokaryotes
Magnetosomes
Volutin
Sulfur granules
Inclusion body which is the stored carbon or energy source
Glycogen/starch
Inclusion body with lipid-like, stored carbon or energy source
Poly-B-hydroxybutyric acid (PHB)
Inclusion body; stored nitrogen source and polymer of amino acids
Cyanophycin
Inclusion body; contains enzymes involved in carbon fixation
Carboxysomes
Impermeable to water but permeable to gases; provides buoyancy for aquatic bacteria
Gas vacuoles (Microcystis)
Inclusion body; not a storage product, allows orientation for navigation towards nutrients, favorable environment
Magnetosomes (magnetite)
Inclusion body; metachromatic granules, polyphosphate reservoir
Volutin
Inclusion body; energy and electron source
Sulfur granules
Synthesis of proteins that will remain in the cell
Matrix ribosomes
Synthesis of proteins for transport outside of cell
Plasma membrane ribosomes
Nuclear or chromatin body, nuclear region; in contact with mesosome or plasma membrane; made up of 60%DNA, some RNA and protein
Nucleoid
Circular dsDNA that can exist and replicate independently of the chromosome or may be integrated with it.
Plasmid
Advantages of genes in plasmid
Drug resistance
Pathogenicity
New metabolic activities
Dormant structure in gram positive bacteria; resistant to heat, UV, chemicals, disinfectants and desiccation
Endospore
Parts of bacterial endospore (from outer to inner)
Exosporium Spore coat Cortex Core wall Core
Stages of bacterial sporulation
Stage 1 - asymmetric cell division
Stage 2 - formation of septum
Stage 3 - mother cell engulfs prespore/forespore
Stage 4 - cortex formation
Stage 5 - spore coat formation
Stage 6 - maturation, cell lysis, disintegration of mother cell
Stages of the transformation of endospore to vegetative cell
Activation
Germination
Outgrowth
Location of endospores
Central
Terminal
Subterminal
Swollen terminal (distended)