Microbial species

Question 1

can microbes survive in every habitat

Answer 1

no

Question 2

terrestrial

Answer 2

in soil formation and essential in ecosystems

Question 3

aquatic

Answer 3

fresh and salt water

Question 4

animals

Answer 4

microbiomes

Question 5

what are extreme environments

Answer 5

hot springs and snow

Question 6

how do you identify bacteria

Answer 6

using genotypic and phenotypic properties. Bacteria are placed in orders, families, genera and species

Question 7

what are microbiota

Answer 7

microorganisms that share body space

Question 8

what are microbiome

Answer 8

full collection of genes of all microbes in a community

Question 9

where is bacteria found

Answer 9

skin, nose, mouth, vagina and intestines

Question 10

obligate aerobes

Answer 10

require oxygen

Question 11

obligate anaerobes

Answer 11

absence of oxygen

Question 12

facultative

Answer 12

can grow in the absence or presence of oxygen due to alternate pathways acquiring energy

Question 13

microaerophilic

Answer 13

require oxygen at reduced level

Question 14

what do complete mediums have

Answer 14

amino acids, purine, pyrimidine, vitamins and inorganic ions

Question 15

what are capsules

Answer 15

well defined mucoid structures that surround the cell wall of some bacteria and have anti-phagocytic properties

Question 16

what are virulence factors

Answer 16

structures that are responsible for ability of a bacterium to produce infection or disease

Question 17

what are virulence factors associated with

Answer 17

adherence, invasiveness, exotoxin and antigenic variation

Question 18

how does bacteria survive

Answer 18

1. antigenic disguise- bacteria coat themselves with host proteins
2. immune suppression- interfere with functions of B and T cells
3. Intracellular survival- hiding in cells where they multiply
4. Release soluble antigens- these antigens bind and neutralise antibodies before reaching the cell

Question 19

what are 2 staining bacteria types

Answer 19

gram stain and acid fast stain

Question 20

what is gram stain

Answer 20

developed by Christian Gram in 1884, Permits bacteria to be separated into two BROAD groups, Gram-positive or Gram-negative.
* Gram-positive bacteria retain the dye crystal violet after treatment with alcohol or acetone.
* As they resist decolourization, they fail to take up a red basic due, safranin and appear purple or violet.
* Gram-negative bacteria take up the counterstain and appear red.

Question 21

what is acid fast stain

Answer 21

developed by Ehrlich in 1882.
Bacteria belonging to the genera Mycobacterium and Nocardia are NOT easily stained with aniline dyes(crystal violet/ safranin).
* Due to high content of cell wall bound lipids.
* Overcome with acid fast stain. Red dye-phenol mixture is first applied to the smear.
* Methylene blue is added as a counterstain

Question 22

what is acid fast staining valuable for

Answer 22

diagnosis of nocardiosis and mycobacterial diseases e.g. TB

Question 23

what is non-acid fast bacteria

Answer 23

staphylococcus epidermidi

Question 24

what is acid- fast bacteria

Answer 24

mycobacterium gordonae

Question 25

what is gram positive bacteria

Answer 25

streptococcus pyogenes

Question 26

what is gram negative bacteria

Answer 26

salmonella

Question 27

what is the plasma membrane

Answer 27

thin, ductile, elastic phospholi[pid bilayer that encloses cytoplasm. The semi-permeable membrane controls the exchange of substances and elctron transport and oxidative phosphorylation take place here

Question 28

what is the cell wall

Answer 28

present in all bacteria except mycoplasma. Confers the rigidity and shape to the cell and acts as a barrier to low molecular weight substances. Can be gram negative or positive

Question 29

What is gram positive

Answer 29

thick, compact and exclusively PG

Question 30

What is gram negative

Answer 30

thinner, less compact and more complex walls