Bacteria

Question 1

Gram Positive

Answer 1

GRAM POSITIVE – Stains BLUE
2 Layers:
1.	Inner cytoplasmic membrane
2.	Outer thick peptidoglycan layer
(60-100% peptidoglycan)

Low lipid content
NO endotoxin
No periplasmic space
No porin channel
Vulnerable to lysozyme and penicillin attack and low molecular weight stuff

Question 2

Gram Negative

Answer 2

GRAM NEGATIVE – Stains RED
3 Layers:
1.	Inner cytoplasmic membrane
2.	Thin peptidoglycan layer
(5-10% peptidoglycan)
 3. Outer membrane with LPS

High lipid content
Endotoxin (LPS) – lipid A (toxic to humans)
Periplasmic space
Resistant to lysozyme and penicillin attack

Question 3

Peptidoglycan

Answer 3

cell wall of bacteria

Question 4

transpeptidase or penicillin binding protein

Answer 4

enzyme that catalyzes the formation of peptidoglycan layer

Question 5

Catalase

Answer 5

breaks down hydrogen peroxide

Question 6

Peroxidase

Answer 6

breaks down hydrogen peroxide

Question 7

Superoxide dismutase

Answer 7

breaks down the superoxide radical

Question 8

Obligate aerobes

Answer 8

Cannot live and grow without oxygen

Question 9

Facultative aerobes

Answer 9

Can grow in air or under low O2 tension

Question 10

Microaerophilic bacteria

Answer 10

aerotolerant anaerobes; requires O2 but less than air

Question 11

Obligate anaerobes

Answer 11

oxygen kills these bacteria, they have no enzymes to protect them; anaerobes infect deep tissues and often are associated with gas production

Question 12

Flagella

Answer 12

mobility

Question 13

Pili

Answer 13

fimbriae; adhesion and binding

Question 14

Capsules

Answer 14

protective walls that surround cell membranes; macrophages and nuetrophils unable to phagocytize
*Opsonization is the body’s solution to encapsulation. By binding antibodies to the capsule the macrophage can phagocytize the bacteria

Question 15

Endospores

Answer 15

Dormancy and resistance to environment (Bacillus and Clostridium)

Question 16

Facultative Intracellular Organisms

Answer 16

Bacteria that are phagocytosed by the host’s macrophages and neutrophils yet survive within these white blood cells unharmed! Once inside, they are safe from antibodies and other immune defenses.
1.	Listeria monocytogenes
2.	Salmonella
3.	Yersinia
4.	Francisella
5.	Brucella
6.	Legionella
7.	Mycobacterium
8.	Nocardia
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Question 17

Exotoxins

Answer 17

Proteins released by both gram-positive and gram-negative bacteria. May cause many disease manifestations. ALL gram positive bacteria have this ability EXCEPT Listeria.

Question 18

Enterotoxins:

Answer 18

exotoxins that work on the GI tract causing diarrhea

Question 19

Neurotoxins:

Answer 19

Act on the nerves or motor end plates causing paralysis. (botulism and tetanus)

Question 20

Pyogenic exotoxins:

Answer 20

Stimulate the release of cytokines and cause rash, fever, toxic shock syndrome

Question 21

Endotoxins

Answer 21

These are lipopolysaccharides (Lipid A) within gram negative outer membrane released with the death of the bacterium. Killing them with antibiotics can lead to SEPTIC SHOCK.

Question 22

Transformation

Answer 22

DNA fragments from one bacterium, released during cell lysis, bind to the cell wall of another bacterium (usually the same species). DNA can incorporate itself in the new bacterium.

Question 23

Transduction

Answer 23

A virus that infects bacteria is a bacteriophage. The bacteriophage carries a piece of bacterial DNA from one bacterium to another.

Question 24

Conjugation

Answer 24

DNA transferred via cell-to cell contact

Question 25

Transposons

Answer 25

Mobile genetic elements (legs). Carry genes for antibiotic resistance and virulence factors.