BACTERIAL MORPHOLOGY Flashcards
(81 cards)
1
Q
Basic shapes of Bacteria
A
Cocci
Bacilli
Spirilla
2
Q
- Greek “kokkos” = berry or seed
- Oval
- Round
- Spherical
- Diameter ranges from 0.5 to 1.0 micrometer
- Example: Staphylococcus, Streptococcus
A
Cocci - Plural
Coccus - Singular
3
Q
- In pairs
- Example: Neisseria gonorrhoeae (gonorrhea), Neisseria
meningitides (Meningococcal)
A
Diplococci
3
Q
Arrangement of Bacteria (Cocci)
A
- Diplococci
- Streptococci
- Staphylococcus
- Sarcina or Octad
- Tetrad
3
Q
- In chains
- Example: Streptococci pyogenes (strep throat), Streptococci mutans (tooth decay)
A
Streptococci
4
Q
- Cube-like packet of 4 cocci
- Example: Aerococcus (found in urine - cause UTI, septicemia/bacteriamia, endocarditis) Tetragenococcus (fermentation of miso)
A
Tetrad
4
Q
- Irregular, grape-like cluster
- Example: Staphylococcus aureus (skin infection, food poisoning)
A
Staphylococcus
5
Q
- Latin = Little staff or wand
- Rod Shaped
- Cylindrical
- Usual size 0.5-1.0 µm wide and from 1-4 µm long
- Example: Escherichia coli, Salmonella
A
Bacilli – Plural
Bacillus (Singular)
6
Q
- Sarcina ventriculi
- tetrad characteristic morphology and able to survive in extreme low pH environment
- Cube-like packet of 8 cocci
- Example: Sarcina aurantiaca (normal flora of skin/GIT body odor)
A
Sarcina or Octad
6
Q
Arrangement of Bacteria (bacilli)
A
- Diplobacilli
- Streptobacilli
- Palisades
- Coccobacillus
6
Q
- two bacilli linked end to end
- Example: Klebsiela rhinoscleromatis (cause URTI,
pneumonia)
A
Diplobacilli
7
Q
- In chains
- Example: Streptobacillus
moniliformis (cause of Rat Bite
Fever)
A
Streptobacilli
8
Q
- Fence - like
- Example: Chlamydia trachomatis
A
Palisades
9
Q
- Short ROD-shaped often mistaken as coccus
- Example: Haemophilus influenza
A
Coccobacillus
10
Q
- Spiral shape
- Curved bacteria
- Can be a gently curved shape to a corkscrew-like
- Many are rigid and capable of movement
- Example: Campylobacter jejuni, Helicobacteri pyori, Treponema pallidum
A
Spirilla (Plural)
Spirillum (Singular)
11
Q
Varieties of Spirillum
A
- Vibrio cholerae
- Spirochetes
11
Q
- Short curved ROD
- Comma-shaped
- Less than one complete turn or
twist in the cell - Vibrios - Plural
A
Vibrio cholerae
12
Q
- Helical shape and flexible bodies
- Move by means of axial filaments
- Example: Spirochaeta,
Treponema, Borrelia, Leptospira
a species (Leptospira interrogans)
A
Spirochetes
13
Q
- Pleo = many
- Morphic = shape
- Deinococcus radiodurans
- Example: Legionella pneumophila
- Ability of some bacteria to alter
their shape or size in response to
environmental conditions
A
Pleomorphic
13
Q
- gram-positive, catalase-positive, aerobic or facultatively anaerobic, generally nonmotile rods
- Example: Corynebacterium diphtheria
A
Club-Shaped
14
Q
– Prokaryotes (bacteria), Eukaryotes (fungi, protozoa, algae)
A
Cellular
15
Q
o Makes it possible to transfer genetic material from one organism to another and deliberately alter DNA
A
- Recombinant DNA technology
15
Q
– Viruses
A
Acellular
16
Q
Microorganisms
A
- Cellular
- Acellular
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o Historical uses of microbes by humans:
Bread production, Alcohol production, Cheese production, Treatment of wounds and lesions, Mining precious metals, Cleaning up human- created contamination
* Microbes and Humans
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o Manipulates the genetics of microbes, plants, and animals for the purpose of creating new products and genetically modified organisms(GMOs)
* Genetic engineering
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o Uses microbes already present or introduced intentionally to restore stability or clean up toxic
* Bioremediation
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o Emerging and reemerging diseases
COVID, AIDS, Hepatitis C, Zika virus, West Nile virus, Tuberculosis
o Associations between noninfectious diseases and microbe
* Microbes and Disease
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* Reproduce rapidly
* Can be grown in large populations in the laboratory
* Cannot be seen directly
* Analyzed through indirect means
* Viewed through microscopes
Microorganisms
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* All living organism are composed of one or more cells
* A Cell is the basic structural and functional unit of all living organisms.
* New cells are only made from pre-existing cells.
Principles of Cell Theory
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* Include plants, animals, fungi, protozoa, and algae
Eukaryotes
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o Have a nucleus where the genetic material of the cell is stored within a membrane, DNA is associated with histones
o Possess membrane-bound organelles that work together to help the cell function.
o Much more complex then prokaryotic cells.
o Can be just one cell or can make up more complex multi-cellular organisms.
o Include plants, animals, fungi, and protists
o divide by mitosis and meiosis
Traits of Eukaryotes
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* Include bacteria
* Their genetic materials in not enclosed within a membrane
* DNA is not associated with histones, they lack membrane-bound organelles
* Cell walls are simplier
* Usually divide by binary fission
Prokaryotes
22
o Do not have a nucleus (genetic material is not stored in the nucleus)
o Have some organelles (structures), but not many.
o Less complicated that eukaryotes
o All bacteria are prokaryotes
o Most are unicellular, but some prokaryotes are multicellular
* Traits of Eukaryotes
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Cell Structures (Prokaryotes)
Extracellular
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* outer membrane (OM), the peptidoglycan cell wall, and the cytoplasmic or inner
membrane (IM)
Envelope Structures
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* Other name: Murein Sacculus
* Principal component is Peptidoglycan
* Functions/Purpose:
o Provides rigid support
o Provides shape to bacteria
o Provides protection from osmotic damage
o Important role in cell division
o Site of action of beta-lactam antibiotics
Cell Wall
25
consists of sugars and amino acids that forms a mesh-like layer outside the plasma membrane, the rigid cell wall characteristic of most bacteria.
Peptidoglycan
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- Composed of lipopolysaccharides (LPS) called Lipid A; which is responsible for it endotoxin activity; Inner core is a polysaccharide called O antigen which is unique for every species
Outer Membrane
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* Thin layer/monolayered
* Surrounded by an outer membrane
* Produce endotoxins
* Components
o Outer Membrane
o Lipoprotein
o Periplasmic space
Gram negative
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- Anchor the outer membrane to the peptidoglycan Layer; Stabilizes the outer membrane of the bacteria
o Lipoprotein
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- A fluid-space between the outer membrane and the inner
plasma membrane;
- Contains enzymes for the breakdown of large non transportable molecules into transportable one and enzymes that serve to detoxify and inactivate antibodies
Periplasmic space
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* Thick layer/multilayered
* Components
o Lipoteichoic acid
o Teichoic acid
o Polysaccharides
Gram Positive
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–attachment
Lipoteichoic acid
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- attachment & surface antigen, act as attachment of the org to the host cells, illicit antibody response, tensile strength
Teichoic acid
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- Include neutral sugars such as mannose, arabinose, rhamnose and glucosamine, Include some acidic sugars : glucuronic acid and mannuronic acid
Polysaccharides
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* Composed of large amount of waxes known as mycolic acids (rich in lipid)
* Makes cell wall hydrophobic in nature
* Can’t stain using the reagents used in gram staining
Acid-fast Cell Wall
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* Other name: Cytoplasmic Membrane; Plasma Membrane; Cell Sack
* Located beneath the cell wall
* It encloses the cytoplasm of cell
* Selectively permeable that allows for transport of selective solutes
* Like a “Skin” around the cell, separates content of cell from the outside
Cell Membrane
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* Functions:
o carries enzymes
o involve in selective permeability, active transport of molecules in & out of the bacteria cell
o For cell recognition
o For adhesion & aggregation
Cell Membrane
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* Pericellular matrix
* Thick layer of material located outside cell wall.
* Produced by cell membrane & secreted outside cell wall
* Made of polysaccharide or polypeptide
* Outermost covering of some bacteria
* Slimy, gelatinous material
Glycocalyx
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Types of Glycocalyx
✓ Strongly Attached
✓ Loosely Attached
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− contains polysaccharides
− highly organized & firmly attached to the cell wall
− indicative of virulence or degree of pathogenicity
− Gelatinous; Firmly attached to cell wall
− Thwart innate defense system thus cause disease
capsules
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Serves as antiphagocytic function, survives longer in human body
capsules
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− Enable adherence
− Diffuse & Irregular
− Detached from cell but still surrounds cell
− not highly organized, not firmly attached to the cell wall
− enables bacteria to glide or slide along solid surfaces
➢ Slime Layer
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* Aggregate of bacteria held together by a mucus like matrix of carbohydrate that adheres to a surface.
Biofilm
40
* Only in Gram Negative
* FLUID filed space between outer membrane & cytoplasmic membrane
* Has enzyme for breakdown of large mol. & transports protein for regulation of osmolality of cells
* Detoxify, inactivate antibiotics
Periplasmic Space
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* Pilus - Latin for 'hair'
* Rigid surface appendages; fine, short
* Made of protein sub-unit “pilins”
* Commonly in gram (-) organisms
Pili or Fimbriae
42
- enables bacteria to adhere or attach in surfaces
Common Pili
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– enables transfer of genetic material from one bacterial cell to
another (conjugation)
Sex Pillus
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* Whip-like structures
* Thread-like structure
* Made of protein sub-unit “flagellin”
* Project from the capsule
* Organs for motility like propeller
* Organelles of locomotion (cell movement)
Flagella (Plural)
Flagellum = singular
43
Types of Flagella
✓ Monotrichus
✓ Lophotrichous
✓ Amphitrichous
✓ Peritrichous
✓ Atrichous
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- single polar (Vibrio cholerae)
Monotrichus
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- at both ends of the bacteria (Spirillum serpens)
Amphitrichous
45
- tuft at one end (Bartonella baciliformis)
Lophotrichous
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- all around the bacillus (Escherichia coli)
Peritrichous
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- without flagellum
Atrichous
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* Other name: Endoflagella
* Usually in spirochetes
* Composed of bundles of “fibrils”
* Arise from end of bacteria cell & spiral around
* Moves the spirochetes in spiral, helical or inchworm manner
* It wraps around the organism bet.
* Layers of cell wall
* Example: Treponema Pallidum (syphilis)
Axial Filaments
49
* Site of protein synthesis
* Target site of some antibiotic
Ribosomes
50
* No true nucleus
* Does not contain NUCLEAR membrane.
* Consist of gene material (DNA), w/c is single, circular or double stranded DNA
Nucleoid
51
* For secretion of substance (chromosomes) by bacterium
* For cell division - binary fission
Mesosome
52
* Found in certain bacteria
* For storage of food & energy
* Example: Metachromatic granules of Corynebacteium diphtheriae)
* Genetic Material (DNA)
Granules or Inclusion Bodies
53
– stored in the nucleoi and holds information a cell needs
to reproduce itself
* Genetic Material (DNA)
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* sturdy structures formed by some bacteria to survive in unfavorable conditions like high heat or freezing temperatures and drying process because of the dipicolinic acid
Endospores/Spores
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o process of spore production
o Occurs when the environmental conditions are detrimental to the bacteria
Sporulation
56
o The process when environmental conditions become favorable, the endospores revert to their vegetative state
Germination
57
* Structure: Also cigar or spindle shaped, double membrane-bound, green
* Function: site of photosynthesis
Chloroplast
58
* Structure membranous system of tunnels and sacs
* Function: Rough-protein synthesis, Smooth- lipid synthesis
Endoplasmic Reticulum
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* Structure - cigar- shaped, double membrane-bound organelle
* Function - Energy transfer by ATP synthesis
Mitochondria
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* Structure: also membranous, kind of like a stack of pancakes
* Function: processing of lipids and proteins
Golgi Apparatus
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* Structure: membrane bound sac containing hydrolytic enzymes
* Function: digestion
Lysosomes
61
* Jelly-like liquid that fills all the empty space in a cell.
* Dense gelatinous solution within the cell membrane that is the primary site for the cell's biochemical and synthetic processes.
* Semi fluid, gelatinous nutrient matrix
* Insoluble H2O
* Storage of granules, including Ribosomes, Endoplasmic Reticulum
Cytoplasm
