General Microbiology

Question 1

Babes Ernst granules

Answer 1

Metachromatic granules or volition granules. They are found in c. Diphtheria. They consist of RnA , poly phosphate and protein. They are stained by Albert stain, Nisser stain , ponder stain, loeffler stain.

Question 2

Intracytoplasmic Inclusion bodies

Answer 2

They are storage units in bacteria.

Question 3

All endotoxins are of lipopolysaccharide except

Answer 3

Those produced by B anthracis.

Question 4

Boivin antigen

Answer 4

Lipopolysachharide of gram negative bacteria

Question 5

Lag phase

Answer 5

Bacteria show maximum cell size during this period.

Question 6

Log phase

Answer 6

There is exponential growth of bacteria

Question 7

Stationary phase g

Answer 7

Nutrients are being used up and there is slow growth of bacteria. They start producing spores , exotoxins , granules and antibiotics.

Question 8

Decline phase

Answer 8

Nutrients are all used up and bacteria start involuting and dying.

Question 9

Obligate aerobes

Answer 9

Brucella
Bacillus cereus
Bordetella
Mycobacteria
Meningococci
Pseudomonas
Legionella

Question 10

Facultative aerobes

Answer 10

Bacillus anthracis
Staphylococcus
Corynebacterium
E. coli
Shigella
Salmonella
Actinomycetes
Mycoplasma

Question 11

What causes organisms to be obligate anaerobes

Answer 11

Lack of superoxide dismutase or catalase

Question 12

Obligate anaerobic bacteria

Answer 12

Clostridium
Bacteroides

Question 13

How do facultative aerobes survive without oxygen

Answer 13

Fermentation pathway

Question 14

Microaerophilic bacteria

Answer 14

Streptococcus
Campylobacter
H pylori
Leptospirosis

Question 15

Contents of gram staining

Answer 15

Crystal violet
Grams iodine- makes the acidic protoplasm of gram positive bacteria more acidic thus causing a strong fixation of basic dye
Ethanol - gram negative bacteria has a highly permeable cell wall allowing the outflow of complex during decolorisation.
Safranin

Question 16

Gram positive organisms

Answer 16

Streptococcus
Staphylococcus
Cornybacterium
Peptostreptococcus
Enterococcus
Listeria
Lactobacillus
No cardio
Bacillus
Actinomycetes
Clostridium.

Question 17

Organisms showing bipolar staining or safety pin staining

Answer 17

Pseudomonas mallei
Pseudomonas pseudomallei
Y pestis
Vibrio parahemolyticus

Question 18

Temperatures for bacterial growth

Answer 18

Psychrophilic - below 20
Mesophilic - between 25- 40
Thermophilic - between 55- 80
Hyperthermophilic - above 75

Question 19

Episome

Answer 19

When plasmid dna is incorporated into the host cell

Question 20

Transformation

Answer 20

When a org takes up dna from the external environment

Question 21

Transduction

Answer 21

Movement of genetic material from one org to another using bacteriophage

Question 22

Conjugation

Answer 22

Using conjugation tube

Question 23

Composition of nutrients agar

Answer 23

Nutrients broth , agar 1%

Question 24

Loeffler serum slope

Answer 24

Horse serum , glucose and nutrient broth

Question 25

Deoxycholate citrate agar

Answer 25

Nutrients agar Sodium deoxycholate Sodium citrate Neutral red lactose

Question 26

Thiosulphate citrate bile salt sucrose

Answer 26

For vibrio cholera Thiosulphate Sucrose Bile salt Bromothymol blue Thymol blue

Question 27

Selenite F broth

Answer 27

Sodium selenite Peptone water

Question 28

Tetrathionate broth

Answer 28

Nutrient broth Sodium Thiosulphate Calcium carbonate Iodine so,union

Question 29

CLED culture medium

Answer 29

It is similar to mac conkey medium. It is used for urinary tract organisms. It is preferred over mac conkey because it supports the growth of staphylococcus , streptococci and candidia

Question 30

Composition of cled media

Answer 30

C- casein peptone Gelatin peptone L - l cysteine Lactose Bromothymol blue Beef extract Agar

Question 31

How is RCM anaerobic

Answer 31

The unsaturated fatty acids, glutathione and casein use up the oxygen. It is heated at 80 to make it free of oxygen.

Question 32

Types of antibiotic sensitivity tests

Answer 32

Diffusion test - Kirby Bauer test Stokes ethu Dilute test - tube Dilution Agar dilution E test- combination

Question 33

Intepreta