Bacteriology overview and basic concepts Flashcards
1
Q
Gram positive: Aerobic cocci (3)
A
Staphylococcus
Streptococcus
Enterococcus
2
Q
Gram positive: Aerobic rods (6)
A
Actinomycetes Bacillus Corynebacterium/Nocardia Listeria Mycobacterium Rhodococcus
3
Q
Gram positive: Anaerobic rods (1)
A
Clostridium
4
Q
Gram negative: Enterobacteriaceae (rod) (5)
A
Esherichia coli/Shigella Salmonella Klebsiella/Enterobacter Proteus Yersinia
5
Q
Gram negative: Non-fermentative rods (7)
A
Bordetella Pseudomonas/Burkholderia Aeromonas/Vibria Pasteurella/Mnnheimia Haemophilus/Hostophilus Brucella Francisella
6
Q
Gram negative: Anaerobic rods (2)
A
Clostridium (pilidorme)
Fusobacterium
7
Q
Curved spiral bacteria (5)
A
Campylobacter/Helicobacter Brachyspira Lawsonia Leptospira Treponema/Borrelia
8
Q
Obligate intracellular bacteria (4)
A
Anaplasma/Ehrlichia
Chlamydia/Chlamydophila
Coxiella
Rickettsia
9
Q
Bacteria without a cell wall (1)?
A
Mycoplasma
10
Q
4 things in common for prokaryotes and eukaryotes?
A
- Cell membrane
- Cytoplasm
- DNA
- Ribosomes (although different ribosome types)
11
Q
No nucleus no membrane enclosed organelles. They tend to be smaller and more simplistic
A
Prokaryotic cells
12
Q
have a nucleus and membrane enclosed organelle. They tend to be larger and more complex
A
Eukaryotic cells
13
Q
What holds bacteria DNA if bacteria do not contain a true nucleus?
A
Nucleoid
14
Q
A jelly like aqueous solution that contains macromolecules, small molecules, and various inorganic ions?
A
Cytoplasm
15
Q
What are proteins (enzymes) such as mRNA, and tRNA considered?
A
Macromolecules
16
Q
precursors to macromolecules, metabolites or vitamins, energy sources
A
small molecules
17
Q
required for enzymatic activity (co factors)
A
Inorganic ions
18
Q
What does the cytoplasm contain?
A
Nucleoid and ribosomes
19
Q
Helps to facilitate chemical reactions and it helps to dissolve solutes (carbohydrates and proteins)
A
Cytoplasm
20
Q
Nucleus like structure that is made up of 60% DNA, contains proteins and RNA
A
Nucleoid
21
Q
a complete set of DNA in bacteria which includes all essential genes
A
Bacterial genome
22
Q
In the nucleoid the DNA is compacted by?
A
Proteins
23
Q
DNA loop formation in the nucleoid is caused by?
A
Nucleoid-associated proteins bound to DNA
24
Q
DNA supercoiling is mediated by these 2 enzymes?
A
DNA gyrase and topoisomerase I
25
Along with proteins involved in DNA compaction, ________ _________ regulate expression of the bacterial genome?
Transcription factors
26
2 types of RNA in the nucleoid?
- mRNA (messenger RNA) encodes for proteins
| - ncRNA (non coding RNA) is involved in DNA organization and expression of the bacterial genome
27
one pair of nucleotide bases that connect the complementary strands of DNA
1 base pair
28
A circular molecule of DNA that replicates separately from the chromosome (not part of the nucleoid)
Plasmid
29
Plasmid genes are not ______ under normal conditions?
essential
30
Size ranges of plasmids?
1 kilobase pairs (Kbp) to several megabase pairs (Mbp)
31
Each plasmid has a defined?
Copy number (regulated by the plasmid) high copy numbers for small plasmid, and low copy numbers for large plasmids
32
Importance of plasmids (2 reasons)
1. Virulence factors (plasmids contains genes associated with causing disease known as virulence factors)
2. Resistance genes (to survive in the presence of antibiotics and other toxic compounds)
3. Conjugation- conjugative plasmids can transfer cell to cell by this process.
33
Plasmids are known as Suitcase DNA because?
because they can travel to other bacterial cells
34
What does the bacterial envelope contain? (6)
1. Cytoplasmic membrane
2. Cell wall (peptidoglycan layer)
3. Periplasmic space
4. Outer membrane (gram negative bacteria)
5. Capsule (some bacteria)
6. Envelope associated : pili/fimbriae, flagella, secretion systems
35
Functions of the bacterial envelope
- Protects cell from the environment or host
- Packages internal components
- provides structural rigidity
- produces energy
- facilitates uptake of nutrients and efflux of toxic substances
36
Some envelope associated components can also?
- enable adhesion to surfaces or motility
- provide resistance to some antibiotics or detergents
- Enable bacterial mating (conjugation)
37
2 main structural classes of bacterial envelope?
1. Gram negative
| 2. Gram positive
38
Gram positive cells stain?
Purple
39
Gram negative cells stain?
Pink
40
Thick peptidoglycan layer and characterized by lipotechoic acid?
Gram positive
41
thin peptidoglycan layer?
Gram negative
42
Bacterial envelope structural class where there is an outer and cytoplasmic membrane. Thin layer of peptigoglycan in the periplasmic space. Lipopolysaccarides in outer membrane (LPS or endotoxins)
Gram negative bacteria
43
Bacterial envelope structural class with a cytoplasmic membrane, thick layer of peptidoglycan and teichoic acids attached to peptidoglycan
Gram positive bacteria
44
What is the cytoplasmic membrane composed of and where is it found?
Phospholipid bilayer and proteins (most do not contain sterols except mycoplasma bacteria)
Found next to the cytoplasm, the inner most membrane
45
What is the phospholipid bilayer comprised of?
Hydrophillic (water loving) Head and two hydrophobic (water fearing) tails
46
Only hydrophobic (lipid soluble) compounds can enter the cell by
passive diffusion across the bilayer
47
What proteins are inside of the cytoplasmic membrane?
-Transport proteins
enable specific transport molecule into the cell and export molecules out of the cytoplasm
- Energy generation and electron transport chain components required for the synthesis of adenosine 5' triphosphate (ATP) by the ATP synthase protein
- PROTEINS that function as anchors or help in assembly of external structures
48
How does the cytoplasmic membrane functions as a selective permeability barrier?
transport proteins mediate passage of hydrophilic substances into and out of the cell
49
Serves as an actor for external structures. Plays a key role in energy generation (proton motive force) and bacterial respiration (electron transport chain)
Cytoplasmic membrane
50
Mesh like essential structure that protects the cell from osmotic lysis and provides mechanical protection
Cell wall
51
What does the cell wall consist of?
Polymers of dissacharides that are cross linked with short chains of amino acids (peptides) by transpeptidase enzymes called penicillin-binding proteins (PBPs)?
52
Common to gram negative bacteria, protective barrier?
Outer membrane
53
What is the importance of the outer membrane found mostly in gram negative bacteria
- Selective permeability barrier: prevents passive diffusion of hydrophobic or large compounds
- Provides resistance to toxic compounds that are 1. hydrophobic or 2. large (~>600 Da). This includes several antibiotics, such as vancomycin and most macrocodes
- Provides tolerance to detergents and bile salts
54
Describe the structure of the outer membrane?
- Asymmetrical lipid bilayer
- Porin proteins
- Transporter proteins
55
Outer leaflet mainly composed of lipopolysaccaride (LPS or endotoxin). The LPS in the outer membrane prevents diffusion of hydrophobic compounds.
Asymmetrical lipid bilayer
56
allow small hydrophilic molecules (such as nutrients) to passively enter the cell.
Porin proteins
57
enable specific transport of important, larger nutrients into the cell
Transporter proteins
58
Structure that does not absorb stain that helps bacteria evade immune system-can prevent engulfment by white blood cells, aids in attachment to some surfaces, increased tolerance to antimicrobial agents
Capsule
59
Another name for white blood cells
Phagocytes
60
Describe the structure of the capsule?
Polysaccharide layer outside of the cell wall or outer membrane, bacterial colonies have a mucoid appearance
61
Surface component that is important for mobility, long filamentous protein structures
Flagella
62
Surface component that aids in adherence to surfaces or bacterial interaction (biofilm). usually shorter and more stiff than flagella
Pipi/fimbriae
63
Surface component that is involved in bacterial conjugation
Sex pilus
64
Surface component where there is a release of proteins into the environment or host. Secreted proteins are typically related to virulence or bacterial communication
Secretion systems
65
Dormant bacteria that can survive in adverse environmental conditions and for long periods of time (high temp, UV radiation, desiccation, and toxic chemicals)
Endospores
66
What can happen when endospores enter a host?
they can revert to their active state and multiply, cause disease
67
Spore forming bacteria?
1. Bacillus- B. anthracis (anthrax), P. Bacillus larvae (American foulbrood)
2. Clostridium- C. perfringens and C. difficile (enterotoxaemia), C. tetani (tetanus), C. botulinum (botulism)
Gram positive forms spores more often
68
Must grow in the presence of O2
Obligate aerobes
69
Absolutely cannot survive in the presence of oxygen?
Obligate anaerobes
70
Can tolerate and live/grow in the presence of O2 but would prefer to live in a oxygen free environment? transport proteins mediate passage
Facultative anaerobes (contains most clinical interest)
71
do not require oxygen as they metabolise energy anaerobically. Unlike obligate anaerobes however, they are not poisoned by oxygen. They can be found evenly spread throughout the test tube.
Aerotolerant anaerobes
