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MEDI1000 > Lecture 1: Intro To Microbiology > Flashcards

Lecture 1: Intro To Microbiology Flashcards

1
Q

What is microbiology?

A

The study of living organisms.

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2
Q

How many organisms are harmless? Provide a percentage value.

A

Most organisms are harmless (87%).

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3
Q

Many organisms are helpful. How so?

A

They have an important role in the food chain e.g. Decomposition & nitrogen fixation

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4
Q

A) what percentage of organisms are opportunistic?
B) Explain what opportunistic means using an example.
C) give examples of such organisms.

A

A) 10%
B) Microbes that are usually harmless but become pathogenic when placed in different conditions.
C) E.g. Bowel flora that find their way into bladder can become pathogenic.

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5
Q

A) How many percent of organisms are overtly pathogenic.
B) explain what overtly pathogenic means.
C) give examples of such organisms.

A

A) 3%
B) organism that usually cause disease when they are present on or in the human body, including upon contact with, an otherwise healthy person.
C) syphilis, tapeworm, tuberculosis and anthrax

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6
Q

What is normal flora?

A

The microbes that naturally inhabit surfaces of the human body.

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7
Q

What is the the total microbial load?

A

> 1013 microbial cells in the body vs 1013 body cells.

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8
Q

How is it possible to have such a large total microbial load? (More microbes than blood cells in body).

A

These organisms occur at sites exposed to, or that communicate with the external environment e.g. skin, nasal passages, mouth, throat, urogenital tract and intestinal tract.

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9
Q

What structures of the body are sterile?

A

Blood, tissues & lower respiratory tract are regarded as sterile.

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10
Q

Where in the body is most of the normal flora found?

A

Most of the normal flora are found in the large intestine.

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11
Q

What is most of the faecal mass composed of?

A

Most of the faecal mass is bacteria (40-60%) and water: Importance of toilet/handwashing!!!!

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12
Q

Name a common bowel/ faecal flora.

A

Escherichia coli

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13
Q

Does normal flora play a beneficial or harmful role in maintaining health?

A

Beneficial role.

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14
Q

Give example of when microbes are used in food and drug industry.

A
  • YEAST: wine, beer, bread
  • FUNGI: cheese, antibiotics
  • BACTERIA: yoghurt, antibiotics, sauerkraut, vinegar
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15
Q

What has the study of infectious disease-causing microbes led to an understanding of?

A
  • Personal/community hygiene: ⬆ hand washing, ⬆ waste treatment/sanitation practices= ⬇ disease
  • Microbial virulence and disease severity: ⬆ virulence of an organism = ⬆ severity
  • Prevention and control measures of microbial disease transmission: Antimicrobial therapy/treatment of infection, Disinfection & Sterilisation
  • Food processing and canning techniques: hygiene, cooking, pasteurisation
  • Industrial microbiology e.g. brewing/baking plus chemicals like acetone
  • Environmental e.g. bioleaching
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16
Q

Who was the 1st person to describe a cell?

They even wrote the first book detailing observations with a microscope.

A

Robert Hooke

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17
Q

This person experimented with dressings soaked in carbolic acid (used as an antiseptic) and was credited for developing antisepsis for surgery.

A

Joseph Lister

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18
Q

What was Antoni van Leeuwenhoek’s contribution to microbiology?

A
  • Further developed the microscope (one with a movable stage)
  • First to describe bacteria including their shapes
  • Reported existence of protozoa in 1674 and bacteria 1676
  • Why did it take two years to discover bacteria? bacteria is SMALLER
  • Very secretive: did not let anyone see microscopes (not even his family or the Tsar of Russia)
  • Microscopy lost for 100 years after his death
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19
Q

What was Ignaz Semmelweis’s (Adrian’s favourite guy) contribution to microbiology?

A
  • First to use handwashing in clinical practice
  • however Physicians refused to wash hands
  • Hand washing only accepted years later after work by Pasteur, Lister, Koch
20
Q

What was Louis Pasteur’s contributions to microbiology?

A
  • Germ theory of fermentation
  • Disproved theory of spontaneous generation (Abiogenesis) (disapproved the thought that you got sick because you were cursed- took misfortune out of disease).
  • Discovered pasteurisation (originally used to prevent spoilage of wine)
  • Aseptic techniques and sterilisation
  • Developed culture methods
  • Took credit for the first anthrax vaccine using Henri Toussaint’s method
21
Q

Who discovered the germ theory of disease? And what other contributions did this person make in microbiology?

A
  • Robert Koch
  • First to study Anthrax and Tuberculosis
  • Discovered the causative organism of cholera (Vibrio cholerae)
  • Found that microorganisms can invade other organisms and cause disease- this is the bases of Koch’s postulates which is the germ theory of disease
  • Devised solid media for culturing bacteria
  • Contributed to developing staining methods for microbes
22
Q

Explain the four points of Koch’s Postulates (Germ Theory Disease).

A
  1. The specific causative agent must be found in every case of an infectious disease
  2. The disease organism must be isolated in pure culture
  3. Inoculation of a sample of culture into a healthy, susceptible animal must produce same disease
  4. The disease organism must be recovered from the infected animal
    • Summary: A specific infectious disease is caused by a specific microbe
23
Q

What were the limitations to Koch’s theory?

A
  • Works with many bacteria (remember Koch was working with anthrax which is Bacillus anthracis, a bacteria)
  • Doesn’t work with viruses or intracellular bacteria (cannot isolate these in pure culture)
  • Doesn’t work with human only pathogens (e.g. HIV only affects humans and there is no animal model of disease)
  • Obviously does not apply to non-infectious disease e.g. diabetes
24
Q

Name the three domains classification of life.

A

Eubacteria (same as bacteria), archaea & eucarya.

25
Q

Give example of bacteria.

A
  • Gram positive bacteria
  • Gram negative bacteria
  • Cyanobacteria: bacteria that obtain energy through photosynthesis
26
Q

What is archae? Give three examples.

A
  • specialised single cell organisms that resemble bacteria
  • This group used to be called the Archaebacteria
  • Methanogens- grow in the absence of O2 and produce methane (CH4)
  • Halophiles- grow/live in areas of high salt concentration (>5 times ocean 3.5%, >17%)
  • Thermophiles- grow in areas of high temperature (45˚C to 122˚C) e.g. hot springs and thermal vents
27
Q

Give examples of eucarya.

A
  • Protozoa
  • Algae
  • Fungi
  • Plants
  • Animals–> us!
28
Q

Why do viruses not fit in the three domains classifications of life?

A
  • require host tissue, living/nonliving & because of this they don’t fit in these domains.
  • they are living/ non living cause have DNA but no metabolism on their own)
29
Q

Name three Classifications of Microorganisms and give examples of each classification.

A
  • PROKARYOTES (lack nuclei in cell): Archaea, Bacteria
  • EUKARYOTES (contain a nuclei in cell): Fungi, Protozoa, Algae
  • Viruses
30
Q 
Algae:
A) eukaryotic or prokaryotic?
B) obtains energy from...
C) produces most of the worlds...
D) is food for...
E) unicellular or multicellular?
A

A) Eukaryotes
B) Obtains energy from sunlight: Photosynthetic (contain chlorophyll like plants)
C) oxygen (O2)
D) water life (phytoplankton)
E) both!
-Multicellular e.g. large algae - seaweed, kelp
-Unicellular- found in ponds, lakes, oceans e.g. diatoms

31
Q

Protozoa:
A) eukaryotic or prokaryotic?
B) motile or not?
C) where do they live?

A

A) Single celled Eukaryotes
B) Most are motile (can move by themselves)- Psuedopodia, cilia or flagella
D) Live mostly in water, some in animal hosts & cause disease e.g. malaria and several that cause diarrhoea

32
Q 
Fungi:
A) eukaryotic or prokaryotic?
B) differ from animals, how?
C) differ from plants, how?
D) names of the two types.
A

A) Eukaryotes
B) Differ from plants because fungi do not use photosynthesis to obtain energy
C) Differ from animals because fungi have a cell wall (we have cell membranes)
D) Two types: moulds and yeasts

33
Q 
Fungi types: moulds
A) multi or unicellular?
B) what do they produce?
C) where do they grow?
D) how do they reproduce?
A

A) multicellular
B) produce hyphae (filaments)
C) grow on fruit and veg
D) reproduce sexually and asexually (spores)

34
Q

Fungi types: yeasts
A) multi or unicellular?
B) what is their shape?
C) how do they reproduce?

A

A) unicellular
B) round or oval
C) asexually by budding

35
Q 
Bacteria:
A) eukaryotic or prokaryotic?
B) multicellular or unicellular?
C) do they have a nucleus?
D) are they smaller or larger than eukaryotes?
E) name and describe the two predominant shapes.
F) how are most differentiated? 
G) what do their cell wall contain?
H) do they all have a cell wall?
A

A) Prokaryotes - single cells
B) unicellular
C) Do not have a nucleus
D) much smaller than eukaryotes
E) Coccus or cocci (round) & Bacillus or bacilli (rod)
F) Most are differentiated by the Gram stain (based on their cell wall structure
G)Cell walls contain polysaccharide and peptidoglycan (very different to ours
H) No. Some bacteria do not have a cell wall (only a plasma membrane) e.g. Mycoplasma sp.

36
Q

Name the medically important bacteria: this bacteria causes lower respiratory infections.

A

Haemophilus influenza

  • gram neg bacteria
  • not the same as seasonal influenza which is a virus
37
Q

Name the medically important bacteria: this bacteria causes Anthrax

A

Bacillus anthracis

38
Q

Name the medically important bacteria: this bacteria causes tuberculosis

A

Myobacterium tuberculosis

39
Q

Name the medically important bacteria: this bacteria causes Gonorrohea

A

Neisseria gonorrhoeae

40
Q

Name the medically important bacteria: this bacteria causes syphlis

A

Treponema pallidum

41
Q

Name the medically important bacteria: this bacteria causes cholera

A

Vibrio cholerae

42
Q

Name the medically important bacteria: this bacteria causes whooping cough

A

Bortetella pertussis

43
Q

Viruses:

a) how small are viruses?
b) what microscope is required to view viruses?

A

a) viruses are very small (25-300 nm)

b) electron microscope

44
Q

In terms of virus structure:

a) is it simple or complex?
b) what is located in the center on the virus?
c) what is that center surrounded by?
d) what is the purpose of this surrounding?
e) some viruses have a second layer around that surrounding. What is this extra layer and what is its purpose?

A

a) simple (not cellular)
b) nucleic acid is located in the centre of viruses, this can either be DNA or RNA. NEVER both.
c) the centre is surrounded by a protein coat called caspid.
d) the purpose of a caspid is to protect the nucleic acid
e) some viruses have a layer around the caspid, this layer is called the lipid envelope and it acts as an extra protective layer.

45
Q

a) Other than animals and humans, what else do viruses infect?
b) what are these type of viruses called?

A

a) viruses can also infect bacteria (meaning bacteria can also get viral infections!)
b) these type viruses are called bacteriophage (abbreviated to phage)

46
Q

Briefly explain how viruses infects bacteria.

A
  • viruses inject their nucleic acid into the host bacteria
  • inside the host cell the virus hijacks and parasitises the cell
  • the cells own metabolism stops procing bacterial cells and starts producing lots of copies of the phage
  • eventually the bacteria is full of phage progeny and it will burst out and infect any neighbouring bacteria they can find.
47
Q

Using Human immunodeficiency virus (HIV), briefly explain how viruses infect humans.

A
  • HIV attaches to the human cell, in the process of gaining entry to the cell.
  • in humans, the virus gets swallowed up by the host cell
  • once inside the host cell, the virus uncoats, the nucleic acid comes out and it hijacks the host machinery.

MEDI1000 (4 decks)

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