Introduction Flashcards Preview

Microbiology > Introduction > Flashcards

Flashcards in Introduction Deck (24)
Loading flashcards...
1
Q

clostridium difficile

  • shape
  • spores
  • gram
  • respiration
  • symptoms
  • mechanism of infection
A
  • rod shape
  • spore forming
  • gram positive
  • strict anaerobe
  • causative agent of antibiotic associated diarrhea and pseudomembranous colitis
  • synthesizes two large toxin proteins (TcdA and TcdB) that disrupts the intestinal epithelium
2
Q

differences between proks and euks

A
  • proks have no nuclear mem
  • proks have no mem bound organelles
  • proks can not do endocytosis
  • a thousand times smaller
3
Q

shape of

  • bacilli
  • cocci
A
  • bacilli = rods

- cocci = spheres

4
Q

gram positive bacteria

A
  • lipoteichoic acid shell

- cytoplasmic membranes containing proteins

5
Q

gram negative

A
  • lipopolysaccharide
  • endotoxin
  • porin in outer mem
  • peptidoglycan between outer and inner membrane
  • cytoplasmic membrane
6
Q

antibiotic target

A

-bacterial cell wall

7
Q

cell wall

A
  • peptidoglycan
  • polysaccharide chains cross linked by short chains of amino acids
  • some barrier function
  • gives cell shape
  • shape determined by pattern of cross link
8
Q

polysaccharide chains of peptidoglycan

A

MGMGMG

  • M= N acetylmuramic acid
  • G= N acetylglucosamine
9
Q

peptide side chains are attached to…

A

N acetylmuramic acid

10
Q

cross linking between side chains

A
  • happens between the side chains attached to M’s
  • specifically between D-ala and L-lys
  • this give a staggered orientation to the peptidoglycans
11
Q

Penicillin

A

-mimics the structure of D-ala, D-ala chains and inhibits cross linking

12
Q

bacterial growth

A
  • done via binary fission
  • exponential
  • determined by the medium that the bacteria is exposed to
  • begins with ecponential then becomes stationary then they begin to die
13
Q

prototrophs

A

-have no requirements for organic compounds other than a simple carbon source

14
Q

auxotrophs

A

bacteria that have more complex nutritional requirements, typically requiring amino acids and or vitamins and or pyrimidines/purines

15
Q

fermentation

A

some bacteria satisfy all of their energy needs by synthesizing ATP through the enzymatic rections of glycolysis

  • also known as substrate level phosphorylation
  • 1,3BPG to 3PG
16
Q

respiration

A

some bacteria generate additional ATP through an electron transport chain and membrane bound ATP synthase

  • Aerobic: electron acceptor is O, producing H2O
  • Anaerobic: electron acceptor is fumarate, nitrate and others
17
Q

different bacteriums response to oxygen

  • strict aerobes
  • strict anaerobes
  • facultative anaerobes
A
  • strict aerobes (mycobacterium tuberculosis), the temrinal electron acceptor for respiration is oxygen
  • strict anaerobes (bacteroides, clostridium in colon) terminal e acceptor are organic molecules
  • facultative anaerobes (escherichia coli in small intestine, vibrio cholerae, streptococcus pneumoniae, pseudomonas aeruginosa
  • some respire when aerobic and ferment when anaerobic
  • some respire both aerobically and anaerobically
18
Q

spores

A
  • hardy, non growing structures that some gram pos bacteria, noteably bacillus and clostridium produce
  • survive for very long time periods of time under conditions of extreme heat, dehydration, toxic chemicals and radiation
  • the low water content of spores allows them to survive harsh environmental conditions
  • sporulation is triggered by nutritional limitation
19
Q

stationary phase

A
  • motility and chemotaxis
  • secretion of degrative enzymes
  • transport of secondary nutrients
  • intracellular catabolic pathways
  • genetic competence
  • antibiotic and toxin production
  • spore formation
20
Q

clostridium difficile

A
  • spore forming

- speudomembranous colitis

21
Q

clostridium botulinum

A
  • spore forming
  • botulism
  • flaccid paralysis
22
Q

clostridium tetani

A
  • spore forming
  • tetanus
  • spastic paralysis
23
Q

bacillus anthracis

A
  • spore forming

- anthrax

24
Q

bacillus cereus

A
  • spore forming

- food poisoning