Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Microbiology > Bacteriology > Flashcards

Bacteriology Flashcards

(107 cards)

Start Studying
1
Q

Who introduced the term microbiology and what did he demonstrate and in what year

A

French Chemist, Louis Pasteur who demonstrated that fermentation was caused by growth of bacteria and yeasts (1857-60).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Who started the controversy of origin of microorganisms and what was their theory

A

Louis Joblot (1718) and John Needham (1749)-

Spontaneous generation.

LJ and JN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Who settled the controversy of origin of microorganisms and what was their theory

A

Lazzaro Spallanzani (1765 and 1776) and Louis Pasteur (1860-64) settled the controversy with the specific conditions required for sterility (115-120oC).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Who first saw microorganisms and in what year and what did he call them

A

Anthony van Leuwenhoek
animalcules
1675

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Who discovered heat resistance spores

A

Ferdinand Cohn (1876) discovered heat resistant spores.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Who developed a method for isolation of pure cultures from mixed cultures on nutrient agar in dried film stained with aniline dyes

A

Robert Koch in 1877

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Baxter are prokaryotes true/false

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the size of bacteria and give an example of the largest bacteria

A

0.5 mm- 0.5 µm

>0.5 mm is Thiomargarita namibiensis and Epulopiscium fishelsoni

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How many bacteria are on earth

A

5 x 10^30

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are mycoplasmas and eg

A

Prokaryotes that differ from true bacteria in their smaller size and their lack of rigid cell wall

E.g. M. genitalium, M. pneumoniae, M. pulmoni

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What leads to extreme pleomorphism and sensitivity to external osmotic pressure in mycoplasma

A

Lack of rigid cell wall

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the diameter of mycoplasma and what is he advantage of their diameter

A

Diameter of 0.15-1 μm

capable of passing through filters that retain bacteria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Where are mycoplasma cultivated

A

Cell free nutrient media

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which organisms are Smallest and simplest organisms capable of autonomous growth

A

Mycoplasma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are Rickettsiae and where do they grow

A

Ricketsia are rod-shaped, spherical or pleomophic Gram-negative organisms
●Smaller than true bacteria but are observable in light microscope
●Mostly grow only in living tissues e.g Rickettsia prowazekii

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are chlamydiae

A

Chlamydiae are similar to reckettsiae but have a more complex intracellular cycle e.g. Chlamydia trachomatis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the function of flagella, sex pilus and common pily( fimbriae) and what is the predominant chemical composition present in all

A

Flagella-Swimming movement

Sex pili-Stabilizes mating bacteria during DNA transfer by conjugation

Common pili-Attachment to surfaces; protection against phagotrophic engulfment

Protein is the predominant chemical composition present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the function of capsule in bacteria and what is the predominant chemical composition present

A

Attachment to surfaces; protection against phagocytic engulfment, occasionally killing or digestion; reserve of nutrients or protection against desiccation

Polysaccharide and occasionally polypeptides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Function of plasma membrane and chemical composition

A

Permeability barrier; transport of solutes; energy generation; location of numerous enzyme systems

Phospholipids and proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Function of Gram positive cell wall and gram negative cell wall and their chemical composition

A

Gram-positive bacteria
Prevents osmotic lysis of cell protoplast and confers rigidity and shape on cells

Chemical composition-Peptidoglycan (murein) complexed with teichoic acids

Gram-negative bacteria
Peptidoglycan prevents osmotic lysis and confers rigidity and shape; outer membrane is permeability barrier; associated LPS and proteins have various functions

Chemical composition
Peptidoglycan (murein) surrounded by phospholipid protein-lipopolysaccharide “outer membrane”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Function of ribosome and chemical composition

A

Sites of translation (protein synthesis)

RNA and protein

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Function of inclusions in bacteria and chemical composition

A

Often reserves of nutrients; additional specialized functions

Chemical composition
Highly variable; carbohydrate, lipid, protein or inorganic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Function of chromosome and Plasmid and their chemical composition

A

Chromosome-Genetic material of cell
Composition -DNA

Plasmid-Extrachromosomal genetic material

Composition -DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is peotidoglycan or murein or mucopeptide made of

A

made of amino sugars N-acetyl glucosamine and N-acetyl muramic acid.
The bases are in an extensive cross-linking between neighbouring peptide chains.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What is Gram +ve wall made of
Peptidoglycan Techoid acid Polysaccharides
26
Peptidoglycan make up 50 – 90% of Gram-positive wall and how many in Gram-negatives ,
5-10%
27
What are techoid acids and their functions
polymeric complexes of ribitol phosphate or glycerol phosphate Functions bind and regulate movement of cations into and out of the cell ●prevent extensive wall breakdown and possible cell lysis during cell growth ●provide much of the cell wall's antigenicity
28
Under what condition will protoplasm of bacteria remain intact and not undergo lysis
Can only be maintained in intact form in hypertonic solutions.
29
Which type of cell wall has more lipids and proteins but is less complex
Gram +ve
30
Where are the hydrophilic and hydrophilic ends of the cell membrane
Hydrophilic is inside | Hydrophobic is outside
31
what may facilitake rapid transfer of mRNA from the nucleus to the ribosomes.
nucleus
32
what is flagella and what do they do
long, thin (about 20 nm), whip like appendages Locomotor organs of bacteria
33
what protein does flagella have and can it move when the cell wal is absent
flagellin | no it cant
34
what is characteristic about protoplast obtained from Baccillus species
they have normal flagella which cant move
35
give the four types of flagella an example of species
monotricous- Vibro cholera lophotrichous- Bartonella bacilliforms amphitricous- spirillum serpans Peritricous- E,coli
36
what is the order of flagellum self assemble
page 38
37
what protein is in fimbrae or pilli
pilin
38
which bacteria are fimbrae\pilli found
gram negative bact
39
how do fimbrae/pilli differ from flagella
they play no role in locomotion | shotter thinner straigter
40
what is the use of sex pili in CERTAIN BACTERIA
forms congugation tubes
41
which genus of bacteria produce spores
Bacillus, anthrax and Clostridium
42
where are spores situated in bacteria
EQUATORIAL-middle SUBTERMINAL-near end TERMINAL-at the ends
43
what is spore feild
Spore field is destined to be the site of formation of the new spore
44
spores arem dormant forms and they dont metabolise and reproduce T OR F
TRUE
45
Describe the stages of spore formation
- the chromatin condenses in SPORE FEILD - chromatin is divided by septum of plasma membrane to form the SPORANGIUM and FORESPORE - thesporangium engulfs the forespore and 2 layers(outer and inner) form - inner layer becomes spore coat and outer layer EXOSPORIUM - cortex is formed in betwwen the spore coat and exosporium - bacteria raptures and spore is released
46
what is the cortex found in endospores made of
calcium and dipicolinic acid
47
what 4 things are spores resistant to that even the vegetative forms are susceptible
- heat, - ultra-violet irradiation - mechanical disruption - most chemical disinfectants
48
what three things differ spores from vegetative forms
chemical composition, antigenic structures and morphology
49
the cortex has low density the cortex has high affinity for dyes t/f it contains most of the mucopeptide of spore
true false true
50
what amino acids are spores rich in and what do these amino acids do
sulpher containing amino acids-eg CESTEINE the disulphide linkages in cestein are responsible for increased radiation resistance
51
what is responsible for heat resistance in spore
calcium dipicolinic acid chelate in exosporium
52
what trigger and conditions initiate sporulation
condition nutrient limitation,by unnatural means, e.g. by mechanical abrasion or by exposure to certain surface active compounds. trigger nutrients usually simple sugars, amino acids and ribosides present in the environment
53
are capsule essential to life of cell?
no, since it can be lost spontaneously by mutation
54
what component ofPATHOGENIC bacteria is viscous polysaccharide gums which give the colony of the organism a mucoid appearancE
CAPSULE
55
WHAT DYES do capsules have low afinity to and what type os staining procedures are capsules demonstrated
aniline dyes negative staining procedures
56
what is the function of the forespore and sporangium
sporangium produces nutriets for the vegetative cell | forespore produces nutrients(proteins) for spore
57
how many layers surround the genetic material of spore
``` 4 inner layer- spore wall cortex spore coat exosporium ```
58
what are metachromatic or volutin granules
granules in many species of bacteria which stains basic dyes intensively
59
what is unusual about the capsules of BACILLUS genus
they have large polypeptides instead of the usual normal polysaccharide
60
what will make a bacteria avirulent
when it loses capsule bu enzyme or mutaion | virulence is being resistant to pathogens
61
what volutin or metachromatic granule is typical of CORYNEBACTERIA
polyphosphate granule
62
what will make volutin granules accumulate
when grown on rich media
63
what are involution forms of volutin
irregular coarse spiral structures of granules
64
when does binary fission occur and what are the steps
Occurs when cell reaches a critical size first stage consists of a division of the nucleus followed by division of the cell membrane and cell wall
65
what is TRANSFORMATION repro in bacteria
Direct uptake and incorporation of exogenous genetic  material from its surroundings through the cell membrane eg of bacteria that undergo transformation-Streptococcus pneumoniae deficient in capsular material Highly energy dependent process
66
what is conjugation
Involves the active passage of genetic material from one cell to another by means of the sex pili F+ strains transfer to F- strains
67
if a transformation reproducing bacteria doesnt need a particular dna what does it do to it
it destroys it
68
why are dna plasmid not incorporated into bacteria when transformation occurs
they can transcribe and translate(PROTEIN SYNTHESIS) on their own. if cell is undergoing transcription plasmid does same
69
what is transduction
transfer of genetic material from Some temperate viruses, do not cause this catastrophic event when they infect their host
70
what are bacteriophages
Viruses, called bacteriophages can attack bacteria. The attack involves the injection of viral DNA into bacterial cells They proceed to make new virus particles and destroy cells
71
what are the three bacterial growth seen in lab
Development of colonies Transformation of a clear broth medium to a turbid suspension Biofilm formation
72
what three factors inhibit bacterial growth
Exhaustion of nutrients Accumulation of toxic metabolic end-products Achievement of a maximum population density
73
The time interval between one cell division and the next is called?
mean generation time | =time b etween divisions/ number of generations= t/y
74
what is the formula for finding number of cells in a generation what is the formula when the initial number for the first generation is unknown
y=number of generation n=cell population yth generation n= 2^y when initial number is unknown= n*, the cell population,n= n* x 2^y log n = log n* + y log 2 y = (log n – log n*) / log 2 log2= 0.301 meanGtime= t/y= 0.301t / (log n – log n*)
75
What are he four main phases of bacterial growth
Lag phase- bacteria prepares for cell division at critical size Exponential/Log phase - actual cell division occurs Stationary- it only occurs when there is nutrient depletion Death- when nutrients are finished
76
What are micro capsule | Can they be seen under microscope
Surface antigens, which exist in a distinct layer external to the cell wall ●E.g. M antigens of the Streptococci and the Vi antigens of S. typhi Insufficiently thick to be seen by ordinary microscopic methods
77
Can cells start dividing in lag phase
Yes
78
What are autotrophs and what do they feed on
Back which utilizes simple imorganic compounds(carbon and nitrogen from Co2 and ammonium salts) They have HIGH SYNTHETIC POWER
79
What are heterotrophs
They require ORGANIC sources of carbon | Carbohydrates, Amino Acids, Preoteins and Fatty acids
80
What is a facultative organism
facultative can undergo aerobic respiration if oxygen is present, but is capable of switching to fermentation if oxygen is absent.
81
Can Nitrate be utilized as an alternative source of nitrogen by some of the heterotrophic bacteria and if yes how
Yes | It has the enzyme nitratase- Nitratase reduces nitrates to ammonia
82
What are the three major growth factors
Amino acids Vitamins Miscellaneous groups eg nitrogenous bases
83
What are non exacting and highly exacting bacteria with egs
Non exacting uses a single amino acid for its growth Eg: S. typhi (single amino acid, tryptophane) Highly exacting uses a lot of amino acid(this may be because they are aromatic types and diffficult to synthesize) Eg: Leuconostoc mesenteroides, which requires 17 amino acids (not self synthesize)
84
Between gram positive and negative which is more exacting
Gram positive
85
What is the use of lipoid acid vitamin
Oxidative decarboxylation of purification acid
86
What is the use of haematin
Part of cytochrome and part of the enzymes PEROXIDASE and CATALASE
87
What is the concentration of Co2 needed by bacteria for initiation of growth
Low concentration
88
Which bacteria species need large amounts of Co2
Gonococci Meningonococci Brucella abortus
89
What are obligatory aerobes and anaerobes
Obligatory aerobes, grow only in its presence of O2 Obligatory anaerobes grow only in absence of oxygen
90
Why can’t ananaerobes thrive under O2
They don’t have enzymes catalase to break down H2O2 to O2
91
What is the optimum temp for pathogenic bacteria and their limits
Pathogenic bacteria optimum growth temp is 37oC with upper (40 to 50oC) and lower growth limits (15 to 20oC)
92
What temperatures do mesophiles, psychrophiles, and thermophiles need
Mesophiles: 20 - 45°C Psychrophiles: less than then 10 - 20°C ●Thermophiles: 40 - 80°C >( or even more) due high heat resistance of their enzymes
93
What are neutrophils, acidophiles and alkaliphiles
●Neutralophiles or Neutrophiles: grow neutral pH 7.4 - 7.6 ●Acidophiles :grow best at acidic pH < 5.5 eg: Acetobacter aceti ●Alkaliphiles: grow best at alkaline pH 8.5 – 11 eg: B. subtilis
94
What are halophiles
tolerate high conc. of salt ●Moderate halophiles -marine bacteria (3% NaCl) ●Extreme halophiles grow well in salt concentrations in excess of 15%. Eg: Salinibacter ruber
95
What are Osmotolerant bacteria, Osmophiles, Barotolerant and Barophiles
Osmotolerant bacteria: grow in high solute conc. Osmophiles: grow best at high osmotic pressures Barotolerant bacteria: grow at very high hydrostatic pressures Barophiles: grow best at high hydrostatic pressures
96
How does light kill bacteria and how do some bacteria protect themselves
formation of singlet oxygen (free radical) causes death of bacterial cells Some produce pigments that protect them ●E.g. yellow, orange or red carotenoid pigments interfere with the formation and action of singlet oxygen
97
Where are culture media prepared from and sources
Media prepared from protein by acid or enzymic digestion sources ●Muscle tissue (meat), ●Casein (milk protein) ●Blood fibrin
98
Why is Nacl added to culture media
To optimize the tonicity
99
How can liquid media be solidified
may be solidified by a natural carbohydrate gelling agent, agar derived from seaweed. (found in the cell wall of red algae, especially genus Gelidium. E.g. Palmaria polysiphonia)
100
Who discovered gram staining
Discovered by a Danish Physician, Hans Christian Gram, in 1884
101
What are the four steps of gram staining
Step 1: apply primary stain (crystal violet) Step 2: apply mordant (iodine) Step 3: apply decolourising agent (acetone/ethanol) Step 4: apply counter/secondary/contrast stain (safranin)
102
What are the basic building blocks of murein
NAG and N-Acetyl Muramic acid
103
What is the function of the amino acids on the peptidoglycan
They link the peptidoglycan units together in horizontal and cross sectional bridges Are peptide bonds
104
What are the two types of technic acid
Wall and membrane(lipo) it hold the cell wall when the bacteria is dividing into two Stability ,transport of certain items and have antigenic functions
105
Why are gram negative said to be more complex
Gram negative have lps layer so are said to be biochemically complex
106
What is protplast and spheroplast
Protoplasts is gram +ve that loses its cell wall artificially and sphero is gram neg
107
Ribosomes are in two forms, what are they and what is their sedimentation coefficient
he maker form has a sedimentation of 30s and the bigger form has 50 s They combine to form 70 s

Microbiology (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions