introduction to microbiology

Question 1

The study of very tiny organisms

Answer 1

microbiology

Question 2

the study of microorganisms that is capable of infecting and causing diseases for human

Answer 2

medical microbiology

Question 3

what are the characteristics of bacteria

Answer 3

-Unicellular
-primitive nucleus
no nuclear membrane

Question 4

the genome of bacteria is

Answer 4

Single circular double stranded DNA
can harbour plasmids

Question 5

Define plasmids

Answer 5

small circular DNA

Question 6

where does the bacteria mostly develop

Answer 6

in liquid or solid media

Question 7

when does the bacteria can be seen

Answer 7

when the colony is formed

Question 8

organisms adapt to new environment
grow in size
making metabolic enzymes

Answer 8

Lag phase

Question 9

what are the typical growth curve in favourable conditions

Answer 9

1-lag
2- log
3-stationary
4-decline

Question 10

in what phase does the antibiotics work

Answer 10

log

Question 11

the rabid growth happen in…

Answer 11

log

Question 12

nutrients begin to deplete in what phase ?

Answer 12

stationary

Question 13

the toxic products accumulates
in what phase

Answer 13

in stationary

Question 14

the number of dead cells = living cells

Answer 14

stationary

Question 15

cells stop dividing

Answer 15

stationary

Question 16

what happen during decline phase

Answer 16

number of living cells less than the dead cells

Question 17

what is the optimal ph for bacteria to grow

Answer 17

7

Question 18

the natural range of ph oc bacteria to live is ?

Answer 18

from .5 to 10.5

Question 19

the bacteria that live in extreme ph is?

Answer 19

acidophils and alkalophils

Question 20

the optimal temperature for bacteria is

Answer 20

37 c

Question 21

the important medically species live in temperature

Answer 21

from 25 to 40

Question 22

bacteria needs to live in most temperatures
is

Answer 22

water

Question 23

the effect of o2 in obligate Aerobe

Answer 23

utilized for aerobic respiration

Question 24

In aerobic environment the obligate Aerobe

Answer 24

grow

Question 25

the effect of o2 in obligate Anaerobe

Answer 25

Toxic

Question 26

facultative Anaerobe/Aerobe

Answer 26

not required for growth but utilized when present

Question 27

the effect of o2 in microaerophile

Answer 27

required at low level below 0.2

Question 28

the effect of o2 in aerotolerant Anaerobe

Answer 28

not required and not utilized no benefit

Question 29

function of cytoplasmic membrane are:

Answer 29

Selective permeability. — Active transport of nutrients. — Secretion & excretion of toxins — Site of respiration. — Cell wall synthesis. — Role in DNA replication.

Question 30

bacterial cell wall functions:

Answer 30

1- Rigid structure that maintains the shape of bacteria. 2- Osmotically insensitive; it protects the cytoplasmic membrane from bursting in hypotonic solutions. 3- Participate in cell division. 4- The cell wall composition plays role in determining the cell's reaction to gram stain.

Question 31

gram positive cell wall contain

Answer 31

peptidoglycan (thick) Teichoic acid

Question 32

what is responsible for cell wall rigidity

Answer 32

peptidoglycan

Question 33

peptidoglycan contain :

Answer 33

Sugar derivatives – N-acetyl muramic acid – N-acetyl glucosamine * Amino acids – D and L alanine; glutamic acid – AND EITHER Lysine or diaminopimelic acid (DAP)

Question 34

layers of gram negative cell wall

Answer 34

-cytoplasmic membrane. -periplasmic space : (lying between cytoplasmic membrane and outer layer) -outer membrane (OM) layer composed of lipopolysaccharide.

Question 35

periplasmic space contents:

Answer 35

contain a gel like substance composed of proteins and enzymes including the thin peptidoglycan.)

Question 36

composed of lipopolysaccharide (LPS) called endotoxin with special channels consisting of protein molecules called porins.

Answer 36

outer membrane OM

Question 37

are species of bacteria which are naturally devoid of cell wall. They are the only bacterial species deficient in cell wall.

Answer 37

mycoplasm

Question 38

mycoplasm shape

Answer 38

pleomorphic

Question 39

mare not destroyed by penicillin which acts on the bacterial cell wall, and can not be stained with gram stain.

Answer 39

mycoplasm

Question 40

what ore other techniques that used to differniate bacteria

Answer 40

Acid-fast staining * Waxy cells do not readily Gram stain * Mycobacteria and Ziehl Neelsen stain . Structural stains * Spores * Flagella * Capsules

Question 41

endospores function :

Answer 41

Resistance to – Heat, radiation, chemicals * Environmental dispersal

Question 42

how can endospores visuilased

Answer 42

Malachite green as primary stain and safranin as counterstain.

Question 43

organs of motility in all motile bacteria.

Answer 43

flagella

Question 44

flagella function:

Answer 44

They move the bacteria towards nutrients and other attractants.

Question 45

where does the flagella attached

Answer 45

basal body in cytoplasmic membrane

Question 46

how is movement of bacteria mediated ?

Answer 46

random untill the cell reaches the chemical or physical agents

Question 47

examples of bacteria movement :

Answer 47

Chemotaxis – response to chemicals Phototaxis – response to light Aerotaxis – response to oxygen Osmotaxis – response to ionic strength Hydrotaxis – response to water

Question 48

where is the attatchement of pilli

Answer 48

extend outwards from the cell surface.

Question 49

where the pilli usually found

Answer 49

gram negative

Question 50

the flagella composed of

Answer 50

subunits of a protein, pilin.