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MEDI1000 > Introduction to Microbiology P1&2 > Flashcards

Introduction to Microbiology P1&2 Flashcards

(75 cards)

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1
Q

In scientific nomenclature which part is the genus and which is the species - Staphylococcus aureus

A

Genus: Staphylococcus
Species: aureus

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2
Q

When writing or typing latin names of biological organisms, how must both component names be presented?

A

Italicised or underlined

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3
Q

Approximately what percentage of microbes are pathogenic?

A

3%

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4
Q

Approximately what percentage of microbes are harmless?

A

87%

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5
Q

Name 3 beneficial uses microbes in our society

A

Yeast: Bread
Fungi: Cheese, antibiotics
Bacteria: yogurt, antibiotics

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6
Q

Which scientist first described the cell?

A

Robert Hooke

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7
Q

Which scientist first described bacteria and their shape?

A

Antoni van Leeuwenhoek

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8
Q

Which doctor first used handwashing to reduce clinical infection?

A

Ignaz Semmelweis

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9
Q

in 1870 which doctor was the first to use antisepsis for surgery?

A

Joseph Lister

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10
Q

What is abiogenesis and who disproved that this was how infections started

A

Abiogenesis: Theory of spontaneous generation

Louis Pasteur

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11
Q

Which scientist discovered pasteurisation? What was it first used for?

A

Louis Pasteur

Originally to prevent spoilage of wine

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12
Q

Which scientist first demonstrated that micro-organisms caused infectious diseases? What were the 2 diseases studied?

A

Robert Koch
1- Anthrax
2- Tuberculosis

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13
Q

What is a pure culture?

A

Population of certain type of cells cultured and grown separately from any other type of cell

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14
Q

List Koch’s postulates

A

1- Specific causative agent must be found in every case of infectious diseases
2- Disease organism isolated in pure culture
3- Inoculation of sample of culture into healthy + susceptible animal. Animal must produce the disease
4- Diseased organism must be recovered from infected animal

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15
Q

What are the limitations to Koch’s postulates

A
  • Works with many bacteria
  • Does not work with viruses
  • Does not work with human only pathogens
  • Does not apply to non-infectious diseases
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16
Q

List the 3 domains of life

A

1- Bacteria
2- Archaea
3- Eucarya

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17
Q

What are the principle members for each domain of life?

A

1- Bacteria: Gram negative + positive
2- Archaea: halophiles, thermophiles. methanogens
3- Eucarya: Protozoa, fungi, algae

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18
Q

What is the main difference between eukaryotic and prokaryotic cells?

A

Eukaryotic: Contain nuclei
Prokaryotic: No nuclei

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19
Q

What are the key features of algae?

A
  • Eukaryotic
  • Contain chlorophyll; obtain energy from photosynthesis
  • multicellular and unicellular
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20
Q

List the 3 mechanisms of motility for protozoa

A

1- Cilia
2- Fimbriae
3- Pseudopodia

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21
Q

Fungi are prokaryotic (T or F)

A

False

Fungi have nuclei

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22
Q

How do fungi differ from plants and animals

A

Plants: No chlorophyll; cannot photosynthesise for energy
Animal: Has cell wall

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23
Q

Name two types of fungi

A

Moulds

Yeast

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24
Q

How do moulds and yeast differ to each other?

A

Moulds: Multicellular, reproduce asexually and sexually (spores)
Yeast: Unicellular, reproduce asexually (budding)

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25
What is the name of the process of yeast reproduction?
Budding
26
The cell wall of bacteria contain polysaccharide and peptidoglycan (T or F)
True
27
Name the two structures that make up all viruses
- Nucleic acid (DNA or RNA) - Capsid (protein coat)
28
What is the name of specialised group of viruses that infect bacterial cells?
Bacteriophage
29
What is the glycocalyx?
- Gelatinous material, coats surface of some bacteria | - Made up of polypeptides and/or polysaccharides
30
Describe the two types of glycocalyx
``` 1- Capsule - Highly organised - Firmly attached - Protect against phagocytosis - Some typed by capsule composition 2- Slime - Not highly organised - Not firmly attached - Helps bacteria to slide onto surfaced - Protect from drying ```
31
Describe the function of flagella
Motility
32
Describe the function of pili and fimbriae
Fimbriae: Adherence Pili: Adherence and conjugation (Passing DNA from one organism to another)
33
What is the main difference between gram positive and gram negative?
Gram positive: Stains purple, thick layer of peptidoglycan, teichoic acid, lipoteichoic acid Gram negative: Stains pink, thin layer of peptidoglycan. lipopolysaccharide present in outer membrane
34
List the steps of gram stain
``` 1- Heat fix smear 2- Crystal violet 3- Iodine 4- Alcohol 5- Carbol Fuchsia ```
35
How do bacteria reproduce?
Asexually; binary fission Single cell -> two identical daughter cells Chromosome duplicates; same genetic material in both cells
36
List the 4 growth phases in a broth culture
1- Lag phase 2- Exponential Phase 3- Stationary phase 4- Death/decline phase
37
What are mesophiles, psychrophiles, obligate anaerobes, facultative anaerobes and Carboxyphiles?
Examples of ideal conditions for bacterial growth
38
What are mesophile and psychrophiles?
Ideal temperature conditions Mesophile: 10-45 degrees. Optimum: 37 degrees Psychrophiles: 0 - <20 degrees. Optimum: 15 or lower
39
What are: Obligate anaerobes Facultative anaerobes Carboxyphiles
Atmospheric conditions 1- Growth in complete absence of O2 2- Grow with/without O2 3- Grow in increased concentrations of CO2
40
Describe bacterial respiration
- Obligate aerobes and facultative microbes - Oxygen required ``` Krebs Cycle - Uses pyruvic acid - 2 ATP produced - CO2 produced Electron Transport Chain - Redox reactions - Many ATP produced - H2O produced ``` - Overall produces ATP, CO2, H2O
41
Describe bacterial fermentation
- Obligate anaerobes and facultative microbes - Absence of oxygen - Uses pyruvic acid - Low ATP yield - Produces organic wastes; alcohol and acids
42
``` Describe glycolysis: 1- Starting carbohydrate 2- Storage molecule 3- End product 4- Net energy molecules produced ```
``` - Anaerobic; no oxygen 1- Glucose C6H12O6 2- ATP 3- 2 pyruvic acid molecule 4- 2 ATP (4 produced, 2 used) ```
43
Differentiate between catabolism and anabolism
Catabolism: Breakdown of chemical bonds Larger molecules -> smaller molecules Anabolism: Formation of chemical bonds Smaller molecules -> larger molecules
44
Differentiate between oxidation and reduction
Oxidation: Loss of electrons Reduction: Gain of electrons
45
What are the enzymes that are spreading factors? What is the role of enzymes in this regard?
``` Enzyme breakdown health connective tissue - Kill host cells - Evade immune system 1- Collagenase 2- Hyaluronidase ```
46
What factors are considered when culturing bacteria?
``` Temperature Atmospheric conditions Moisture Ph Osomolarity (salt) Nutrientsa ```
47
What is a microbial biofilm?
Found on wet surfaces Composed of microbes, cell debris and extracellular matrix Matrix composed of e.c slime layer
48
How does plaque leads to tooth decay?
Sucrose in diet degraded by bacteria producing acids | Increased bacteria = acid production = demineralisation
49
What is a virulence factor? Give examples.
Traits that give microbe ability to cause disease 1 - Toxins; endotoxins and exotoxins 2- Adherence factors; fimbriae, pili, glycocalyx 3- Enzymes: production and secretion 4- Production haemolysins
50
What is the difference between exotoxin and endotoxin?
Exotoxin: - Gram positive - Secreted by living cell (cell does not have to die before toxin is secreted) - Passes through cell wall, secreted into extracellular Endotoxin: - Gram negative -Toxic compound: lipopolysaccharide (embedded in cell call) - Toxin released when cell dies
51
What are the three types of haemolysis on a blood agar plate?
Rupture of red blood cells 1- Beta: Complete lysis 2- Alpha: Partial lysis 3- Gamma: No haemolysis
52
Describe the function of condenser lens, iris diaphragm
1- Focusses light through specimen | 2- Controls amount of light entering condenser
53
How is total magnification calculated?
Objective size x ocular size
54
How would you increase the contrast looking at an unstained preparation with bright field illumination?
Closing condenser diaphragm = increased contrast
55
What is the difference of a mixed and pure culture? How can you tell a difference?
Mixed: More than one colony type present Pure: one type of colony type present Identify any different shapes, colours, size
56
Explain selective and differential media
Selective: Allow certain bacterial growth, inhibiting others Differential: Contains substances to allow different bacteria to be distinguished
57
Four principle shapes of bacteria
Bacilli (rod) Cocci (round) Spirals Vibrio (comma)
58
Four types of arrangement
Diplococcus (pairs) Chains Clusters Single
59
What are other methods to identify an unknown organism?
Serotyping Detection of virulence factors Molecular techniques Observe biochemical characteristics
60
Difference between incubation period and invasive period
``` Incubation: - No symptoms - Initial invading microbes invade body - Must overcome host defences Invasive: - Disease is identifiable - Increase in microbes ```
61
What is a microaerophile?
Microorganism that requires oxygen to survive | Levels must be lower than present atmosphere
62
Which parts of the body are considered sterile?
Blood Tissues Lower respiratory tract
63
What is an opportunist pathogen? | Give an example
Normally considered harmless Become pathogenic when place in different conditions Bowel flora that enter bladder
64
Define Mutualism
Symbiotic relationship | Both members benefit
65
Commensalism
Symbiotic relationship One member benefits Other not harmed
66
Parasitism
One member benefits Other is harmed Amensalism or antagonism
67
Describe the characteristics of Eukaryotes
- Simple cell wall: Fungi, algae and plants - No cell wall: Protozoa, animals - Nuclear membrane - Nucleus - Larger ribosomes - Larger than prokaryotes - Reproduce by mitosis/meiosis
68
Describe the characteristics of Prokaryotes
- Archaea and bacteria - Smaller than eukaryotes (0.1 - 10 micrometres) - No nuclear membrane - No nucleus - Complex cell wall (with peptidoglycan for bacteria/eubacteria) - Smaller ribosomes - Reproduce by binary fission
69
Why did it take Leeuwenhoek longer to discover bacteria (after protozoa)?
Bacteria much smaller than protozoa | Microscope not advanced to detect presence of bacteria
70
What is the role of glycocalyces with bacteria?
virulence; bacteria often become more pathogenic | Adherence, protection from phagocytosis, some protection from antibiotics
71
Define sporulation
Bacteria can make a copy of their DNA with some cytoplasm and enclose it in thick layers of protein
72
What are the two spore forming genera of bacteria??
Bacillus | Clostridium
73
What are acidophiles, alkalophiles and neutrophiles?
Examples of ideal pH conditions for bacterial growth
74
What are the stages of infectious diseases? What happens at each stage?
Incubation: No symptoms, invading microbes colonise body site Prodromal: Mild symptoms invasive: Identifiable disease with increase in microbes Decline: Decline in microbes Convalescence: Recovery
75
How do enzymes cause the rapid spread of infection?
1- Invasive bacteria reach epithelial surface 2- Bacteria produce hylauronidase + collagenase 3- Bacteria invade deeper tissues

MEDI1000 (2 decks)

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