MICROBIAL GROWTH PT.2

Question 1

Classification of Culture Media

Answer 1

Culture media according to consistency
Culture media according to composition
Culture media according to their function
and use.

Question 2

Culture media according to consistency:

Answer 2

Liquid media
Solidified media

Question 3

are used for growth of pure
batch cultures

Answer 3

Liquid media

Question 4

contain agar and are
used widely for the isolation of pure
cultures, for estimating viable bacterial
populations, and a variety of other
purposes

Answer 4

Solidified media

Question 5

Culture media according to composition.

Answer 5

Chemically-defined (synthetic) medium
Complex (undefined) medium

Question 6

is one in which the exact chemical
composition is known.

Answer 6

Chemically-defined (synthetic) medium

Question 7

is one in
which the exact chemical constitution of
the medium is not known

Answer 7

Complex (undefined) medium

Question 8

Complex (undefined) medium Also known as

Answer 8

basal medium

Question 9

Culture media according to their function
and use.

Answer 9

Enrichment media
Supportive media
Selective media
Differential media

Question 10

contain specific
nutrients required for the growth of
bacterial pathogens that may be present
alone or with other bacterial species in a
patient specimen

Answer 10

Enrichment media

Question 11

Enrichment media EXAMPLE

Answer 11

Blood, Chocolate agar

Question 12

contain nutrients that
support growth of most non-fastidious
organisms without giving any organism a
growth advantage.

Answer 12

Supportive media

Question 13

contain one or more
agents that are inhibitory to all organisms
except those being sought.

Answer 13

Selective media

Question 14

Selective media EXAMPLE

Answer 14

MacConkey agar, (GRAM -)
Eosin methylene blue (GRAM -)

Question 15

employ some factors
that allows colonies of one bacterial
species or type to exhibit certain metabolic
or culture characteristics that can be used
to distinguish them from other bacteria
growing on the same agar plate.

Answer 15

Differential media

Question 16

Bacterial Mutation

Answer 16

Spontaneous mutation
Induced mutation
Caused by transposable
genetic elements

Question 17

mutations have no identifiable
cause and are rare.

Answer 17

Spontaneous mutations

Question 18

mutations are due to chemical or
physical mutagens

Answer 18

Induced mutations

Question 19

Induced mutations uses

Answer 19

UV light, nitrous acid,
base analogs etc.

Question 20

Three major types of transposable elements

Answer 20

Insertion sequences
Transposons
Transposable phages (Mu)

Question 21

They are segments of DNA that encode
enzymes for site specific recombination and
have distinct nucleotides at their terminals.

Answer 21

Insertion sequences

Question 22

They are larger than insertion
sequences, code for protein
synthesis and can induce mutation
the same way as insertion sequences.

Answer 22

Transposons

Question 23

They can alternate between lytic and
lysogenic growth. During lysogeny

Answer 23

Transposable phages (Mu)

Question 24

They can insert themselves anywhere on the
bacterial chromosome, and later transpose from
one location to another, inactivating the
bacterial gene just as other transposable
elements.

Answer 24

Transposable phages (Mu)

Question 25

Bacterial Recombination

Answer 25

Transformation
Conjugation
Transduction

Question 26

Donor cells lyse, a fragment of DNA is released and passed
into a recipient cell.
Enzyme dissolves one strand of the fragment, and the other
strand displaces a homologous segment of the recipient’s
DNA.
The recipient then has a recombinant DNA.
The displaced fragment is dissolved by an enzyme.

Answer 26

Transformation

Question 27

Only _____ can be transformed and DNA of both
organisms must be similar.

Answer 27

competent cells

Question 28

is the ability to take up DNA from the
environment

Answer 28

Competence

Question 29

It involves two live bacteria, donor and recipient,
with the transfer of genetic material from a plasmid.

Answer 29

Conjugation

Question 30

The donor is F+, has fertility factor and codes for
sex pilus.
Once there is contact with the F - or recipient, plasmid DNA begins to replicate by the ______

Answer 30

Rolling
circle method

Question 31

The transfer of genetic material from one organism
to another by a transducing phage.

Answer 31

Transduction

Question 32

There are two types of transducing phages:

Answer 32

Lytic
Lysogenic

Question 33

The phage reproduces and causes the bacterium
to lyse.

Answer 33

Lytic

Question 34

This is a virulent phage.

Answer 34

Lytic

Question 35

The phage codes for a repressor protein which
prevents its own replication.

Answer 35

Lysogenic

Question 36

This is a temperate phage.

Answer 36

Lysogenic

Question 37

There are two types of transductions

Answer 37

Generalized Transduction
Restricted or Specialized Transduction

Question 38

A lytic virus uses the bacterial machinery to
make viruses.
☐The bacterium lyse and viral parts are
released.

Answer 38

Generalized Transduction

Question 39

Only genes adjacent to the phage can be
transduced.

Answer 39

Restricted or Specialized Transduction