Intro To Mcrobiology- Lecture 9/28/21

Question 1

Clostridium difficile

Answer 1

• Rod-shaped, spore forming, gram-positive bacterium
• Strict anaerobes
• Human pathogen
• Synthesizes two large toxic proteins (TcdA, TcdB) that disrupt intestinal epithelium

Question 2

Microorganism examples (6)

Answer 2

• Bacteria
• Viruses
• Yeast and fungi
• Protozoa
• Archaea (commensalism, no known pathogens)
• Bacteriophage (viruses of bacteria)

Question 3

Bacteria shape (2)

Answer 3

• Bacilli (rod)

- Cocci (spheres)

Question 4

Gram-positive

Answer 4

Positive gram stain based on cell wall characteristics, thick layer of peptidoglycan

Question 5

Gram negative bacteria

Answer 5

Have a thin layer of peptidoglycan with a second membrane with inner phospholayer and lipopolysaccharide outer layer

Question 6

Polysaccharide chains of peptidoglycan

Answer 6

Alternating chains of N-acetylmuramic acid and N-acetylglucosamine

Question 7

Peptide side-chains

Answer 7

Attached to N-acetylmuramic acid, contain L and D aminoacids which can cross link

Question 8

Penicillin mechanism of action

Answer 8

Stops growing bacteria by mimicking D-Ala D-Ala dipeptides

Question 9

Bacterial growth curve

Answer 9

Lag, exponential, stationary, death

Question 10

Characteristic of stationary phase (5)

Answer 10

Secretion of degradation enzyme
Transport of secondary nutrients
Intracellular catabolic pathways
Motility and chemotaxis
Toxin production

Question 11

Prototrophs

Answer 11

Bacteria that have no requirements for organic compounds other that simple carbon source

Question 12

Auxotrophs

Answer 12

Bacteria that have more complex nutritional requirements, typically requiring aa, vit, nucleotides

Question 13

Fermentation

Answer 13

Satisfying energy requirements through the synthesis of ATP from glycolysis

Question 14

Respiration

Answer 14

Generation of additional ATP through an electron transport chain and membrane bound ATP synthase

Question 15

Aerobic respiration

Answer 15

Uses O2 as a terminal electron receptor

Question 16

Anaerobic Respiration

Answer 16

Uses a different organic electron acceptor, fumarate, nitrate, other

Question 17

Strict aerobes

Answer 17

Terminal electron acceptor has to be O2

Ex: mycobacterium tuberculosis

Question 18

Strict anaerobes

Answer 18

Terminal electron acceptor is organic molecule, die in O2

Ex: Bacteroides Clostridium

Question 19

Facultative Anaerobes

Answer 19

Some respire when aerobic and ferment when anaerobic, some respire in both conditions

Question 20

Spores

Answer 20

NOn-growing structures that some gram positive bacteria do in limited nutrients, can survive very harsh conditions. Created in stationary phase

Question 21

Spore forming pathogens

Answer 21

• Clostridium difficile
• Clostridium Botulinum
• Clostridium Tetani
• Bacillus anthracis
• Bacillus cereus