Basic Bacteriology Flashcards
TRUE or FALSE
Exotoxins are proteins found in the LPS membrane of gram
negative bacteria.
FALSE
Exotoxins - gram positive and some
gram negative bacteria
Endotoxins - gram negative bacteria
only
What nutritional condition do capnophilic bacteria, like Neisseria and Haemophilus, need for survival?
a. 5 to 10% carbon dioxide
b. Minute amount of nitrogen
c. Absolute lack of oxygen
d. Pure oxygen
A
Explanation: “Capno” - carbon dioxide “Philic” - like/affinity = carbon dioxide lovers C Obligate anaerobes D Obligate aerobes
Which of these descriptions is used to denote bacteria which require 2 to 10% oxygen for aerobic respiration?
a. Aerotolerant anaerobe
b. Facultative anaerobe
c. Microaerophilic
d. Capnophilic
C
A - Cannot use oxygen for growth nor as hydrogen acceptor B - Do not require oxygen but grows better with its presence D - Carbon dioxide is needed for growth
What is the process that eliminates all pathogenic
microorganisms, EXCEPT bacterial spores?
a. Radiation
b. Sterilization
c. Disinfection
d. Pasteurization
C
A - Damages DNA
B INCLUDING bacterial spores
D- Denatures proteins
What bacterial cell structure contains alternating
N-acetyl-glucosamine and N-ac etyl-muramic acid?
a. Periplasmic space
b. Capsule
c. Outer membrane
d. Peptidoglycan
D
Recall
Which type of flagellar arrangement refers to the presence of flagella distributed over the entire cell?
a. Peritrichous
b. Amphitrichous
c. Lophotrichous
d. Monotrichous
A
Amphitrichous - single flagellum at both ends Lophotrichous - bundle of flagella at one or both ends Monotrichous - single flagellum at one end
Choose the corresponding pair regarding the phases of the microbial growth curve with their corresponding growth rates.
a. Lag phase : zero growth rate
b. Log phase : negative (death)
c. Maximum stationary : constant
d. Decline : constant
A
Lag Phase - No growth only increase in cell mass Log Phase - Organisms grow at a maximum rate (exponential rate) Stationary Phase - No net growth Decline Phase - Death rate increases as it reaches a steady level
Which of these processes use moist heat under pressure?
a. Open flaming of inoculating loops during aseptic
technique
b. Immersion of glasswares to chlorinated water
c. Use of the autoclave during culture media preparation
d. Exposure of a laboratory to ultra violet lamps after
working
C
A - Dry Heat
B - Chemical process
D - Ionizing Radiation
Which of the statement is TRUE regarding exotoxins
a. It is produced by gram negative bacteria
b. It has low toxicity
c. It can be converted to toxoids
C
A - found in gram positive bacteria
(gram negatives only have
endotoxins)
B - high toxicity
Which of these bacterial cell structures is unique only to gram positive cell walls?
a. Periplasmic space
b. Endotoxin later
c. Lipopolysaccharide layer
d. Teichoic acid
D
Recall
What is the composition of the prokaryotic ribosome?
a. 40S and 50S
b. 30S and 50S
c. 40S and 60S
d. 70S and 80S
B
Eukaryotes - 40S and 60S
Which of these organisms are able to live aerobically and
anaerobically, like the enterobacteriaceae?
a. Obligate aerobes
b. Facultative anaerobes
c. Strict anaerobes
d. Microaerophilic
B
A require oxygen
C require the absence of oxygen
D require 2-10% oxygen
