(P) Lec 1: Bacterial Morphology and Ultrastructure, Physiology, Metabolism, Genetics and Nutrition (Part 1) Flashcards
This prefix means that it “cannot be seen with the naked eyes”
Micro (penis)
What are the 5 important microbial groups?
- Prions
- Viruses
- Bacteria
- Fungi
- Parasites
In which kingdom do microorganisms belong to?
Protista
Microorganisms include what 2 subgroups?
Prokaryotes and Eukaryotes
TOF: Not all of the important microbial groups are under the classification of Prokaryote or Eukaryote
True (e.g. prions and viruses)
TOF: Prions and viruses are cells
False (they are NOT cells)
Identify if Prokaryote or Eukaryote:
Bacteria
Prokaryote
Identify if Prokaryote or Eukaryote:
Parasites, Fungi, Plants, and Animals
Eukaryote
Identify if Prokaryote or Eukaryote:
Smaller in size
Prokaryote
Identify if Prokaryote or Eukaryote:
Larger in size
Eukaryote
Identify if Prokaryote or Eukaryote:
Has a true nucleus with a nuclear envelope
Eukaryote
Identify if Prokaryote or Eukaryote:
Has no true nucleus
Prokaryote
Identify if Prokaryote or Eukaryote:
The cytoplasmic structure is less complex and harbors less structures/organelles
Prokaryote
Identify if Prokaryote or Eukaryote:
The cytoplasmic structure is more complex and harbors more structures/organelles
Eukaryote
Identify if Prokaryote or Eukaryote:
The cell wall is more complex
Prokaryote
Identify if Prokaryote or Eukaryote:
The cell wall is less complex
Eukaryote
TOF: Prokaryotes have a nucleoid and nuclear membrane
False (no nuclear membrane)
What is the average size range of a prokaryote?
Around 1-10 micrometers
These are infectious particles associated with subacute, progressive, and degenerative diseases of the CNS
Prions
These are aka abnormally/misfolded proteins
Prions
What are examples of diseases caused by prions?
Creutzfeldt-Jakob Disease (CJD) and Mad Cow Disease
A degenerative disease of the brain associated with “Kuru” (cannibalism in Papua New Guinea) wherein female tribe members eat the brains of the corpses
Creutzfeldt-Jakob Disease (CJD); caused by a prion
What is the smallest among the important microbial groups?
Prions
These are acellular, obligate intracellular parasites, that are not visible with the light microscope
Viruses
This term means that the parasite cannot live without a host cell, like in the case of viruses
Obligate
Since some viruses are enveloped while some are not, when do enveloped viruses start to dissolve their envelopes and multiply?
Once inside the host cell
TOF: Viruses contain organelles/biosynthetic machinery along with enzymes
False (no organelles/biosynthetic machinery, only a few enzymes)
What do viruses contain as genetic material?
RNA or DNA
A virus is called as ______ if it comes with a bacterial host
Bacteriophage
TOF: The airborne mode of transmission deals with particles that fall on the ground/surface
False (those are droplets, airborne particles stay in the atmosphere as they are smaller)
This is the largest group of organism of medical significance
Bacteria
These are unicellular and lack a nuclear membrane and true nucleus
Bacteria
TOF: Bacteria are classified as prokaryotic because of the absence of the mitochondria, ER, and golgi bodies (organelles)
True
Bacterial Morphology
When asked about bacterial morphology, you are to state the three which are?
- Shape
- Arrangement
- Gram Stain Reaction (+ or -)
Bacterial Morphology (shape)
Circular/spherical
Coccus/Cocci
Bacterial Morphology (shape)
Short and rod-shaped
Coccobacillus
Bacterial Morphology (shape)
Comma-shaped/curved rod
Vibrio
Bacterial Morphology (shape)
Rod-shaped
Bacillus/Bacilli
Bacterial Morphology (shape)
Curved rod to corkscrew-shaped
Spirillum
Bacterial Morphology (shape)
Spiral-shaped and is very small
Spirochetes
Bacterial Morphology (shape)
This can only be visualized via darkfield microscopy (e.g. Treponema spp.; causative agent of syphilis)
Spirochete
Bacterial Morphology (arrangement)
What do you call Cocci that are in pairs?
Diplococci
Bacterial Morphology (arrangement)
What is an example of Cocci in chains/bead-formation?
Streptococci
Bacterial Morphology (arrangement)
What do you call Cocci that are in groups of 4?
Tetrads
Bacterial Morphology (arrangement)
What do you call Cocci that are in groups of 8?
Sarcina
Bacterial Morphology (arrangement)
What is an example of Cocci in clusters/grape-formation?
Staphylococci
Bacterial Morphology (arrangement)
What do you call lone Coccus?
Singly
Bacterial Morphology (arrangement)
What do you call lone Bacillus?
Singly
Bacterial Morphology (arrangement)
What is an example of Bacilli in palisading/picket fence formation?
Corynebacterium diphtheriae
Gram Staining
Refers to air drying the sample and using heat to let it adhere to the slide
Heat-fixed cells
Gram Staining
The primary stain
Crystal Violet
Gram Staining
This accentuates the primary stain to attach better to the bacteria (a mordant)
Gram’s Iodine
Gram Staining
Aka the decolorizer
Ethyl Alcohol
Gram Staining
Aka the counterstain
Safranin
Gram Staining (identify if positive or negative)
After administering crystal violet: Purple
Both (+) and (-)
Gram Staining (identify if positive or negative)
After administering Gram’s iodine: Purple
Both (+) and (-)
Gram Staining (identify if positive or negative)
After administering alcohol: Purple
Positive
Gram Staining (identify if positive or negative)
After administering alcohol: Colorless
Negative
Gram Staining (identify if positive or negative)
After administering safranin: Purple
Positive
Gram Staining (identify if positive or negative)
After administering safranin: Pink
Negative
Aka “differential staining” wherein the bacteria are identified to be positive or negative
Gram Staining
Gram Staining
How long is crystal violet stained for?
30 seconds
Gram Staining
How long is iodine administered for?
1 minute
Gram Staining
How long is alcohol administered for?
5-15 seconds
Gram Staining
How long is safranin stained for?
1 minute
Gram Staining (identify if positive or negative)
This organism’s cell wall is 50% of the dry weight of the cell envelope
Positive
Gram Staining (identify if positive or negative)
This organism’s cell wall is 2-10% of the dry weight of the cell envelope
Negative
All cocci are what gram stain? (except for some)
Positive (circles are purple)
What cocci bacteria are not gram-positive? (the exemptions)
- Neisseria
- Veilonella
- Moraxella
(Mnemonics: NVM)
All bacilli are what gram stain? (except for some)
Negative (rods are red/pink)
What bacilli bacteria are not gram-negative? (the exemptions)
- Mycobacterium
- Corynebacterium
- Bacillus
- Clostridium
- Actinomyces
- Streptomyces
Less common ones:
1. Erysipelothrix
2. Listeria
3. Nocardia
4. Anything ending in bacterium (e.g. Proprionibacterium, Eubacterium, and Bifidobacterium)
TOF: The bacterial structure is important for its pathogenesis and virulence factors
True
Cell Envelope
What are the 4 parts of the cell envelope?
- Outer membrane
- Cell wall
- Periplasmic space
- Cytoplasmic (cell) membrane
Cell Envelope
The outer membrane only exists for what type of bacteria?
Gram-Negative
Cell Envelope
This is the initial barrier to the environment, it is a bilayer composed of lipopolysaccharides
Outer Membrane
Cell Envelope
The outer membrane consists of this substance which functions as an endotoxin
Lipid A (note: endotoxins are for gram-negative while exotoxins are for gram-positive)
Cell Envelope
The outer membrane consists of this substance which contains antigens (H and O antigens) and can be used for serologic typing
Major surface antigenic determinants
Cell Envelope
The outer membrane consists of this water-filled structure that controls the passage of nutrients and other solutes
Porins
Cell Envelope
Aka “Murein” or the “Peptidoglycan Layer”
Cell Wall
Cell Envelope
This gives the cell its shape and strength; it is the site of action for antibiotics, and it is also the basis of staining
Cell Wall
Cell Envelope
The cell wall is composed of what subunits?
Disaccharide-Pentapeptide Subunits
(N-acetylglucosamide and N-acetylmuramic acid)
Cell Envelope
TOF: Some bacteria have jelly cell walls made up of mycolic acid
False (waxy, not jelly)
Cell Envelope
Bacteria that have waxy cell walls have this key component that contributes to their virulence hence becoming harder to kill/penetrate
Mycolic Acid
Cell Envelope
What is an example of a bacterium with a waxy cell wall?
Mycobacterium spp. (takes 6 months to treat)
Cell Envelope
This consists of gel-like substances that assist in the capture of nutrients from the environment; it contains enzymes that degrade macromolecules and detoxifies evironmental solutes
Periplasmic Membrane
Cell Envelope
Not all bacteria are encapsulated, hence why they are called as?
An appendage
Cell Envelope
The periplasmic membrane space contains these which are responsible for metabolism and detoxification
Enzymes
Cell Envelope
This contains enzymes vital to cellular metabolism and serves as an additional osmotic barrier
Cell Membrane
Cell Envelope
This transports solute into and out of the cell, it houses enzymes involved in the synthesis of the outer membrane and cell wall, it aids in the assembly and secretion of extracytoplasmic and extracellular substances, and it generates chemical energy
Cell Membrane
Cell Appendages
This is composed of high molecular weight polysaccharides, it is anti-phagocytic, and it facilitates and maintains bacterial colonization of biologic and inanimate surfaces
Capsule
Cell Appendages
The capsule facilitates and maintains bacterial colonization of biologic and inanimate surfaces through the formation of what?
Slime layers or biofilms
Cell Appendages
TOF: When an organism is encapsulated, it is non-motile
True
Cell Appendages
These promote the uptake of the pathogen by a macrophage by inducing phagocytosis (microbial recognition and killing of encapsulated bacteria)
Opsonins
Cell Appendages
The Bacillus anthracis capsule is made up of what?
Poly-D-glutamic acid (PGA)
Cell Appendages
This is the causative agent of anthrax
Bacillus anthracis
Cell Appendages
What is the more common form of anthrax found in cows and sheep?
Cutaneous anthrax
Cell Appendages
The capsule’s slime layer is aka?
Glycocalyx
Cell Appendages
This capsule component is loosely adherent to the bacteria (functions as an adhesive) composed of polysaccharide fibrils surrounding some bacterial cell walls
Slime Layer/ Glycocalyx
Cell Appendages
These capsule components are aggregates of bacterial cells which enhance nutrient uptake and often excludes antimicrobials
Biofilm
Cell Appendages
Organisms can produce these on medical implant devices (e.g. heart valves, prostheses, and catheters) which can cause diseases
Biofilms
Cell Appendages
This common biofilm producer is a normal inhabitant of the skin but is seen in catheter-related infections
Staphylococcus epidermidis
Cell Appendages
This common biofilm producer is a normal inhabitant of the mouth but is seen in cases of dental plaques
Streptococcus mutans
What are the representative encapsulated organisms? (YSKBHPNC)
- Yersinia pestis
- Streptococcus pneumoniae
- Klebsiella pneumoniae
- Bacillus anthracis
- Haemophilus influenza
- Pseudomonas aeruginosa
- Neisseria meningitidis
- Cryptococcus neoformans
This representative encapsulated organism was the causative agent for the black plague
Yersinia pestis
What are the 4 other important capsule producers?
- Escherichia coli
- Bacillus anthracis
- Salmonella enteritica subsp. typhi
- Streptococcus pneumoniae
Cell Appendages
These are hair-like proteinaceous structures that extend from the cell membrane into the external environment and may serve as adhesins
Fimbriae or Pili
Cell Appendages
What are the 2 types of fimbriae/pili?
- Common pili
- Sex pili
Cell Appendages
This type of pili are involved in bacterial adherence and gram-positive cell conjugation
Common pili (common = positive)
Cell Appendages
This type of pili are involved in the attachment of donor and recipient bacteria in gram-negative cell conjugation
Sex pili (sex = negative)
Cell Appendages
These participate in the conjugation of bacteria (mechanism of gene transfer)
Fimbriae/Pili
Cell Appendages
This requires cell-to-cell contact, and through which genes may be transferred from one bacterial cell to another (ex: genes for antimicrobial resistance)
Conjugation
Cell Appendages
TOF: Fimbriae/Pili are for motility
False
Cell Appendages
Functions include motility, chemotaxis, and bacterial pathogenicity
Flagella
Cell Appendages
The flagella is composed of what protein?
Flagellin
Cell Appendages
Kind of bacteria based on flagella presentation:
A single flagellum at one end of the cell
Monotrichous
Cell Appendages
Kind of bacteria based on flagella presentation:
A group of flagella at one end of the cell
Lophotrichous
Cell Appendages
Kind of bacteria based on flagella presentation:
Single flagellum at both ends of the cell
Amphitrichous
Cell Appendages
Kind of bacteria based on flagella presentation:
The entire cell surface covered with flagella
Peritrichous
Cell Interior
Contains (+) enzymes for metabolism and detoxification and is the site for protein synthesis
Cytoplasm
Cell Interior
TOF: The cytoplasm of bacteria contains golgi bodies
False
Cell Interior
If a cell component has a gel-like structure (e.g. cytoplasm) it has what?
Enzymes
Cell Interior
Serves as the nutrient reservoir for the bacteria
Inclusion bodies
Cell Interior
The cell’s inclusion bodies contain?
Glycogen and Polyphosphate Granules
Cell Interior
What is the storage form of glucose and inorganic phosphates? (2 answers)
Glycogen and Polyphosphate Granules
Cell Interior
Inclusion bodies are visualized using what methods?
Staining methods
Cell Interior
Corynebacteria’s characteristic feature is the presence of what?
Metachromatic or Volutin Granules (appears in a pallisading arrangement and beaded)
Cell Interior
Invaginations in the bacterial cell structure
Mesosomes
Cell Interior
Highly coiled DNA intermixed with RNA, polyamines, and various proteins
Nucleus/Nucleoid
Cell Interior
TOF: Bacterial chromosomes are enclosed within a membrane-bound nucleus
False (it exists as a nucleoid)
Cell Interior
Small, circular, extrachromasomal (nonchromosomal) dsDNA capable of self-replication which becomes integrated into the bacterial DNA
Plasmids
Cell Interior
Plasmids contains these genes that can confer protective properties (3 answers)
- Antibiotic resistance
- Virulence factors
- Transmissibility to other bacteria
Cell Interior
A process by which cells transform from an actively metabolic and growing state to a dormant state
Sporulation
Cell Interior
This happens to some bacteria when they are exposed to unfavorable conditions (excessive dryness, nutrient scarcity, toxin accumulation, etc.)
Sporulation
Cell Interior
This process induces an increase in cell envelope thickness & strength (a keratin coat)
Sporulation
Cell Interior
Are dormant, thick-walled structures produced by some bacteria that allow them to survive for long periods of time
Endospores
Cell Interior
What are endospores made out of?
Calcium Dipicolinate
Cell Interior
What are the only 2 bacterial genera that can produce spores?
Bacillus and Clostridium
Cell Interior
TOF: Spores do not have resistance to heat, dessication (extreme dryness), and various chemicals
False
Cell Interior
Endospores will remain in a dormant state until favorable conditions for what are encountered again?
Growth
Cell Interior
This bacteria emerges from its dormant state once ingested and into the GIT which will eventually cause food poisoning
Bacillus cereus
