Part III - Basic Principles Flashcards
What is temperature range of bacteria optimized to grow in humans?
35-40 degrees C
What was Girolamo Fracastoro known for?
Proposed that epidemic diseases are caused by transferable spores “seeds”
What are thermophiles?
range between 45 and 70 degrees C
Oxygen requirements for obligate aerobes?
ABSOLUTE requirement for O2. Use it to generate energy
Oxygen requirements for obligate anaerobes?
Cannot multiply if O2 is present - often killed by traces of O2
Oxygen requirements for facultative anaerobes?
grow better if O2 is present, but can grow without it
Oxygen requirements for microaerophiles?
Require small amouns of O2 for aerobic respiration. Higher conc. Of O2 is inhibitory
Oxygen requirements for aerotolerant anaerobes?
indifferent to O2. Can grow in its presence but don?t use it to transform energy
What is superoxide ion?
O2-
What is superoxide capable of?
participating in destructive rxns, potentially lethal to cell
What is H2O2 generated as, and is it damaging to cell?
Oxidizing agent, does not damage cell as much as superoxide
Is OH- very damaging?
Very damaging, but transient in cells
What enzymes are used by cells to degrade toxins?
superoxide dismutase, catalase
What does superoxide dismutase do?
converts O2- to H2O2 and O2
What does catalase do?
converts H2O2 to H2O and O2
What is the typical internal pH of cells?
Near 7
What pH environment do neutrophiles live in?
pH 5-8
What pH environment do acidophiles live in?
ph <5.5
What pH environment do alkalophiles live in?
pH >8.5
Water requirements for microbial growth?
All microbes require water for growth but some can survive/multiply in high salt
How do some microbes survive in high salt?
increasing solute concentration inside cell
What is osmotolerant bacteria?
tolerant of high salt environments (up to 10%)
What are halophiles?
REQUIRE high levels of salt to live and multiply (>10%)
What are mesophiles?
range between 25 and 45 degrees C
What are psychrophiles?
range between -5 and 15 degrees C
ATP yield from fermentation?
2-4 ATP
What is oxidative phosphorylation?
Use of reducing power of NADH and FADH2 to synthesize ATP
What is the chemiosmotic theory?
ATP synthesized as result of proton motive force generated by passing e- along chain
Net gain of NADH from glycolysis?
2 NADH
What is one molecule of glucose converted to in glycolysis?
Two molecules of pyruvate
When does glycolysis occur?
In presence OR absence of oxygen
What is catabolism?
Breakdown of carbs, lipids, proteins
What is biochemical testing (for bacterial ID)?
test for utilization of different substrates (sugars)
What are the morphological characteristics of bacteria? (5)
- colony characteristics 2. cell shape 3. presence of capsule/endospore 4. staining (G+ vs G-) 5. Locomotion (presence of flagella)
Are endospores reproductive structures?
NO - protective
What are sex pili used for?
Transfer of DNA during conjugation
What are pili?
Shorter thinner protein structure with similar structure to flagella
What are storage granules aka?
inclusion bodies, granular inclusions
What are storage granules?
accumulations of high molecular weight polymers
What are ribosomes?
organelles composed of ribosomal RNA and protein
What is a plasmid?
small extrachromosomal DNA - capable of autonomous replication
What type of bacteria are mesosomes found in?
BOTH gram positive and gram negative
What type of mechanisms are used by bacterial cell membrane?
Secretory and excretory
How often is facilitated diffusion used in bacteria?
Rarely
What is facilitated diffusion?
passive transport
Structure of cytoplasmic cell membrane?
Phospholipid bilayer
What causes rigidity of cell wall?
High sterol content
What is an acid fast cell wall?
Group of microbes that do not readily take up stain
What is outer membrane of G- cell walls made of?
Lipopolysaccharides (LPS)
What color do Gram positive bacteria stain?
Purple
Cell wall structure of Gram positive bacteria?
Thick peptidoglycan layer surrounds cell membrane
What is a slime layer?
Loose structure, permits particles to pass
Function of glycocalyx?
Adherence, physical barrier, protective walls
What shape are pleomorphic bacteria?
variable In shape, lack a single characteristic form
What shape are spirochete bacteria?
Spiral shaped. Unique motility
What shape are coccobacillus bacteria?
rod-shaped with round ends (mistaken for coccus)
What are Koch’s postulates?
Must be:
Found in all cases of the disease examined
Isolated and maintained in pure culture
Capable of reproducing infection
Retrieved from an inoculated animal and cultured again
What are Koch’s postulates used for?
To establish that an organism is the cause of a disease
What was Robert Koch known for?
Discovered anthrax, tuberculosis, and cholera bacilli (TB vaccine)
Koch’s postulates
What was Louis Pasteur known for?
Demonstrated that growth of microorganisms in broth is NOT due to spontaneous generation
Showed that microorganisms contaminate fermenting beverages
Invented pasteurization
Proposed aseptic techniques
What was Friedrich Henle known for?
Proposed criteria for proving that microorganisms cause human disease - the germ theory
What was Ignaz Semmelweis known for?
Proposed connection between contamination and puerperal fever, instituted policy of washing hands between patients
What was Anton van Leeuwenhoek known for?
Father of Microbiology
Constructed first microscopes
First to observe and describe microbes (“animalcules”)
What was Robert Hooke known for?
Coined the term “cell” in his book Micrographia
What is Fredrick Griffith known for?
Experiments suggested that bacteria are capable of transferring genetic information
What are Watson and Crick known for?
Determined structure of DNA
What shape are cocci bacteria?
Spherical
What shape are bacillus bacteria?
rod-shaped
What are Avery, McCarty and MacLeod known for?
Concluded that “transforming substance” found by Griffith was DNA
What is John Cairns known for?
First described bacterial chromosome as circular
What shape are spirillum bacteria?
Spiral
What is the glycocalyx?
Inclusive term for polysaccharide-containing material lying outside cell
What is a capsule?
Rigid structure, tight matrix
What is a virulence factor?
resists phagocytosis (of bacteria)
What is virulence?
“to cause disease”
What is cell wall of bacteria made of?
Peptidoglycan - provides rigidity
Where are peptidoglycans found?
only in bacteria
What do Gram positive bacteria cell walls contain (create negative charge)?
Teichoic acids
Structure of Gram negative cell wall?
Cell membrane - Peptidoglycan - Outer membrane
Why is LPS known as an endotoxin?
It is toxic and is inherent part of cell wall
What is LPS composed of?
lipid A, core polysaccharide, O specific polysaccharide
What is the toxic portion of LPS?
Lipid A
What color do Gram negative bacteria stain?
Pink
Why do acid fast cell walls not take up stain?
Due to lipid content of cell wall
Which genus are all acid fast?
Mycobacterium
What genus of bacteria lack a cell wall?
Mycoplasma
What is the fluid mosaic model?
Fluid structure containing proteins moving in bilayer
What does it mean that phospholipid bilayer is selectively permeable?
Few molecules move through via diffusion
What is active transport?
transport proteins used to move substances across membrane. Requires energy
What is the site of oxidative phosphorylation in bacteria?
Cell membrane
What is the location of enzymes used in DNA replication in bacteria?
Cell membrane - no nucleus
What do proteins that extrude from the surface of bacterial cell membrane act as?
Receptors in cell metabolism, cell communication
What is a mesosome?
Invagination of cytoplasmic membrane that can form into vesicles
What may mesosomes play a role in?
chromosome replication and distribution
What is the periplasmic space?
Space between inner and outer membranes in gram negative cells
What is a nucleoid?
region of bacterial cell containing DNA - usually circular
What are flagella?
long protein structure responsible for most bacterial motility
What can flagella act as?
Virulence factor
What are the 2 types of pili?
peptidoglycan - provides rigidity
What are attachment pili aka?
Fimbriae
What can pili act as?
Virulence factor
What are endospores?
unique dormant cell type produced in response to adverse conditions
How does an endospore act as a virulence factor?
Resist heat, drying, disinfectants
Two Gram + genera that produce endospores?
Bacillus (gangrene, anthrax) and clostridium (botulism, tetany)
What was the earliest classification system?
2 kingdoms (Linnaeus)
What was Woese’s classification system?
5, then 6 kingdoms
Most recent classification system?
3 domain system - bacteria, archaea, eukarya
Bacterial classification system? (order)
Kingdom - Phylum - Class - Order - Family - Genus - Species - Strain
What is usually used to name organisms?
Genus, species
What is molecular taxonomy?
Size of genome, guanine/cytosine content, nucleic acid similarity, protein similarity
What is diagnostic molecular pathology?
Use in vivo hybridization - create fluorescent probe of known DNA, apply to tissue to see if match with complimentary strands present
What is Polymerase Chain Reaction (PCR)?
allows for production of millions of copies of target nucleic acid
What type of primers should be used for PCR?
Speicfic for target
What are immunological tests?
analyze blood serum to search for specific antibodies
What is a serotype?
Indicator that organism possesses specific set of antigens
What is a bacteriophage?
virus that infects bacterium
Why can bacteriophages be used to type bacteria?
Phages are very host specific
What is antibiotic sensitivity testing?
Subject a sample to various antibiotics to test for resistance/susceptibility
What is anabolism?
ATP derived used in synthesis of cellular components
Primary carb used to produce energy?
Glucose
Net gain of ATP from substrate level phosphorylation?
2 ATP
What is pyruvic acid oxidized to in TCA cycle?
water and CO2
Net gain of ATP/NADH/FADH2 from TCA cycle?
2 ATP, 6 NADH, 2 FADH2
What do NADH and FADH2 enter after TCA cycle?
Electron transport chain
What is the final electron acceptor in ETS?
Oxygen
What is aerobic respiration?
Process of transferring electrons from NADH and FADH2 to OXYGEN
What is anaerobic respiration?
In absence of O2, electrons are transferred to an INORGANIC terminal electron acceptor (ex. Sulfur)
What is Fermentation?
In absence of O2, electrons are transferred to an ORGANIC terminal electron acceptor
What organisms use fermentation?
organisms that can’t respire
ATP yield from aerobic respiration?
38 ATP
ATP yield from anaerobic respiration?
30 or less ATP
