Lecture 1 - intro to microbiology

Question 1

list the categories of microorganisms

Answer 1

• bacteria
• archaeans
• protozoa
• molds and yeasts
• viruses

Question 2

what is microbiology?

Answer 2

the study of very small living organisms

Question 3

what is an extremophile?

Answer 3

a microorganism that can live under extreme conditions

Question 4

what is a halophile?

Answer 4

need high salt concentrations

Question 5

what is a thermophile?

Answer 5

can survive at temperatures between 60-120 degrees

Question 6

what is a cryophile?

Answer 6

grows better at temperatures of 15 degrees or lower

Question 7

what is an acidophile?

Answer 7

has an optimum pH level at or below 3

Question 8

what is an alkaliphile?

Answer 8

has optimum growth pH levels of 9 or above

Question 9

what is a xerophile?

Answer 9

grows in extremely dry or desiccating conditions

Question 10

what is the average size of a bacterium?

Answer 10

approximately 10um

Question 11

what is a brightfield microscope used for?

Answer 11

most common, gram staining

Question 12

what is a darkfield microscope used for?

Answer 12

examination of very thin organisms against a dark background

Question 13

what is the magnification of a brightfield microscope limited to?

Answer 13

1000x due to the light that is used.

Question 14

what is a phase contrast microscope use for?

Answer 14

observing unstained live organisms

Question 15

what is a fluorescence microscope used for?

Answer 15

mainly for immunodiagnostic fluorescent dye attached to an organism

Question 16

what is a scanning electron microscope used for?

Answer 16

examination of surface features of cells and viruses, gives illusion of depth

Question 17

what is a transmission electron microscope used for?

Answer 17

examination of cellular and viral ultra-structure, reveals internal features

Question 18

what is the most powerful microscope?

Answer 18

High-resolution transmission electron microscopy

Question 19

what are the taxonomic categories?

Answer 19

• life
• domain
• kingdom
• phylum
• class
• order
• family
• genus
• species

Question 20

what is a strain?

Answer 20

genetic variant of the same species (subtype)

Question 21

what is a serotype?

Answer 21

subtype that can be defined by using specific antibodies

Question 22

what is a pathovar?

Answer 22

subtype with tissue/host specificity

Question 23

what is an isolate?

Answer 23

pure microbial sample obtained from an infected individual (or no variation)

Question 24

what are the two ways to culture bacteria and yeasts?

Answer 24

agar plate and a liquid culture (broth)

Question 25

what is the process of bacterial growth called at the individual level?

Answer 25

binary fission

Question 26

obligate aerobes:

Answer 26

require O2 and there is no fermentation

Question 27

obligate anaerobes:

Answer 27

cannot survive in presence of O2

Question 28

facultative anaerobes:

Answer 28

can metabolise energy aerobically (respiration) or anaerobically (fermentation)

Question 29

microaerophiles:

Answer 29

require O2 but cannot survive in higher concentrations of O2

Question 30

aerotolerant bacteria:

Answer 30

cannot utilize O2 (fermentation only) but are not harmed by O2

Question 31

how can we test for O2 dependency in bacteria?

Answer 31

grow it in thioglycolate broth

Question 32

what are the main bacterial morphology we will be examining?

Answer 32

shape: coccus and bacillus Cell wall: gram +ve and -ve

Question 33

what are the features of gram +ve bacteria?

Answer 33

Have one cell wall with an exterior thick protective peptidoglycan capsule

Question 34

what are the features of a gram -ve bacteria?

Answer 34

have both an inner and an outer membrane, with only a thin peptidoglycan layer between the two

Question 35

what powers a flagella?

Answer 35

proton motive force

Question 36

what are fimbriae/pili?

Answer 36

used for attachment to host cells/other bacteria

Question 37

what is used to transfer genetic material in horizontal gene transfer?

Answer 37

sex pili, which attach to the other bacterium and transfer a single strand of DNA from the plasmid to another bacterium

Question 38

what is a slime layer?

Answer 38

- not highly organised - loosely attached - used for gliding, aggregation

Question 39

what is a capsule?

Answer 39

- highly organised - firmly attached - chemical composition varies - protects bacteria from drying out and the immune system.

Question 40

what is an endospore?

Answer 40

a survival mechanism for bacteria. - can survive very harsh conditions for many years but cannot reproduce

Question 41

what is a protozoa?

Answer 41

a single cell eukaryote

Question 42

what is a metazoa?

Answer 42

multicellular organisms

Question 43

true or false, prokaryotes contain mitochondria, ER and golgi

Answer 43

false

Question 44

where does respiration occur in prokaryotes?

Answer 44

cytoplasmic membrane

Question 45

what environmental conditions is likely to be the most inhibiting factor that microbes encounter on an inanimate object?

Answer 45

water availability

Question 46

Escherichia coli is a Gram-negative bacterium. In taxonomy the term Escherichia refers to the?

Answer 46

genus