Intro To Microbiology Flashcards
State the pathenogenesis of C. Dificile
- Antibiotic Treatment
- Disruption of normal colonic microflora
- Exposure to C. dificile spores, germination and colonization
- Toxin Production
- Damage to Colonic mucosa, inflammation and diarrhea
- Antibiotic Treatment
RELAPSE
What is C. Dificile
- Rod shaped, spore forming, gram positive bacterium
- Strict anaerobe
- Human pathogen –> diarrhea and pseudomenbranous colitis
- Synthesizes two large toxin proteins (TcdA and TcdB) –> disrupt intestinal epithelium
What do Eukaryotes have that Prokaryotes do not?
- Nuclear Membrane
- Membrane bound organelles
- Endocytosis
State the three types of bacterial shape
- Rod (bacilli)
- Sphere (cocci)
- Spiral (spirala)
Define endotoxin
A toxin that is present inside a bacterial cell and is released when the cell disintegrates. It is sometimes responsible for the characteristic symptoms of a disease
What structure is unique to bacteria and a target for antibiotics?
Bacteria Cell Wall
What does the bacteria cell wall consist of and what is its function?
-Consists of peptidoglycan (polysaccharide chain crosslinked by short chain AA)
- Gives barrier function
- Cell shape
What does the polysaccharide peptidoglycan chain consist of (2)?
N-acetylmuramic acid
N-acetylglucosamine
What is the antibiotic that kills newly formed cross links but not already formed cross links?
Penecillin
What is gram positive?
Where bacteria have a thick cell wall (peptidoglycan containing layer)
NO OUTER MEMBRANE
What is a gram negative?
Where bacteria have 2 cell membranes and thin peptidoglycan layer
-stain pink in slide
What are the two bacterial growth requirements?
- autotrophs
2. prototrophs
What is a prototroph?
Where bacteria with no requirements for organic compounds other than a carbon source (sugar and nitrogen)
What is an autotroph?
Bacteria that have more complex requirements, usually requiring AA and/or vitamins, purines
EX. C. dificile
What is the Lag phase in bacterial growth?
Where bacteria senses that it is in a nutrient rich environment
What is the exponential growth in bacterial growth?
Number of cells which increases logarithmically
DOES NOT OCCUR IN NATURE
What is the stationary phase in bacterial growth?
Where cells can no longer grow
SYNTHESIS OF MANY PROTEINS
What is the death phase in bacterial growth?
Constant rate of loss of variable cells
What is fermentation?
Where bacteria are satisfied with energy via glycolysis
What is respiration?
Where bacteria generate ATP through ETC & ATP synthase
What are spores?
Extremely hard, non growing structures that gram + bacteria have
T/F: Spores can survive very longs periods of time and endure extreme heat, dehydration and radiation
TRUE
How does C. Dificile, a strict anaerobe, get transmitted from one person to another?
SPORE FORMATION
Why are there outbreaks of C. Dificile infection in hospitals or long term care facilities?
Spores survive really well –> resistant
Define Strict aerobes
Terminal e- acceptor for respiration=O2
Define Strict Anaerobes
Terminal e-acceptor for respiration=organic molecules
Define Facultative Anaerobes
Some respire when aerobic and ferment when anaerobic
Some respire both aerobicall and anaerobically
A bacterial “coccus” purified from the oral cavity stains Gram-positive. How would it appear under the microscope?
Purple and spherical
What specific cellular structure is responsible for the different staining observed in Gram-negative and Gram-positive bacteria?
Peptidoglycan cell wall
