Bacteria

Question 1

what are 3 characteristics describing bacteria?

Answer 1

unicellular
prokaryotic
reproduce by binary fission

Question 2

What are the 3 common shapes of bacteria?

Answer 2

Coccus- round
bacillus- rod shaped
spiral

Question 3

What type of bacteria tend to be Cocci?

Answer 3

Gram positive bacteria

Question 4

What type of bacteria tend to be Bacillus?

Answer 4

Gram negative bacteria

Question 5

What type of binary fission to bacilli undergo? what restrictions does this have?

Answer 5

Cell division occurs at right angles to the long axis of the cell
only can form chains of bacili

Question 6

Description of Gram positive bacteria?

Answer 6

2 layer envelope: membrane, thick cell wall

binds to TLR2 through LTA (Lipoteichoic acid)

Question 7

Description of Gram negative bacteria?

Answer 7

3 layer envelope: membrane, thin cell wall, outter membrane
bind to TLR4 through LPS
periplasmic space between membrane
outter membrane porins

Question 8

Gram stain process?
color of Gram negative bacteria?
Color of Gram positive bacteria?

Answer 8

Fixation –> crystal violet –>. iodine treatment –> decolorization –> counter stain safranin

Gram negative- PINK
Gram positive- Violet/blue

Question 9

Description of Acid Fast bacteria

Answer 9

2.5 layer envelope: membrane, thick cell wall, acyl layer
binds to TLR 1,2,6
unique: Mycolic acid, wax D, arabinogalactans, sulfolipids

Question 10

Staining procedures of acid fast bacteria

Answer 10

stain with carbolfuchsin (red)
decolorization with acid alcohol (resists decolorization)
counter stain with methylene blue

Question 11

What are the characteristics of peptidoglycan in the cell wall?

Answer 11

alternating repeats of NAM and NAG (sugars)

Tetrapeptide and pentapeptide that connect the strings of sugars

Question 12

What differs between Gram positive and Gram negative in peptidoglycan?

Answer 12

Gram positive: L-lysine

Gram negative: Meso diaminopimelic acid

Question 13

what are the 2 important enzymes required for peptidoglycan synthesis?

Answer 13

Transpeptidase

Transglycosylase

Question 14

What are B lactam antibiotics?

what do these antibiotics targe?

Answer 14

Penicillins
Cephalosporin
Carbapenems

target enzymes required for peptidoglycan synthesis (disrupt peptidoglycan synthesis and cell wall synthesis)

Question 15

which bacteria tend to have flagella?

Answer 15

Bacilli and Spirochetes
NOT cocci (very rare to find flagella in gram positive)

Question 16

what are the 4 arrangments of flagella?

Answer 16

Monotrichous (Vibrio)- single flagellum
Lophotrichous- lots from one end
Amphitrichous- one from each end
Peritrichous (Ecoli)- all over cell

Question 17

Pili and fimbriae description

Answer 17

in both gram positive and negative bacteria
purpose: cell adhesion
fimbriated strains of Ecoli can agglutinate RBC- use mannose to prevent agglutination

Question 18

Slime layer description?

Example of bacteria that has a slime layer?

Answer 18

glycocalyx, loosely associated with cell wall, protects against dehydration and loss of nutrients
ex: acinetobacter (multidrug resistant bacteria)

Question 19

Capsule description

example of bacteria that have capsule?

Answer 19

glycocalyx, tightly associated with cell wall, protects against dehydration/loss of nutrients, adhesion
ex: Klebsiella and Strep

Question 20

Endospore description

Which 2 bacteria have this feature?

Answer 20

dormant, tough, temporarily non-reproductive structure
Bacillus Anthracis and Clostridium
Destroyed by burning or autoclaving

Question 21

What are the 3 conditions that need to use a bactericidal antimicrobial rather than a bactericidal antimicrobial

Answer 21

Endocarditis
Neutropenia
Meningitis