Microbiology in General Flashcards
(112 cards)
1
Q
Define microbiology?
A
It is defined as the study of organisms too small to be seen with the naked eye.
2
Q
Give examples of organisms that are too small to be seen with the naked eye?
A
Viruses Bacteria Algae Fungi Protozoa
3
Q
What are microbes?
A
Microbes are products of evolution, consequence of natural selection operating upon vast array of generally diverse organisms.
4
Q
Who was the first person to advocate handwashing?
A
Ignas Semmelweis.
Note: In 1840’s, he advocated handwashing to prevent transmission of puerperal fever from one person to another.
5
Q
Who was the first person that introduced the antiseptic system?
A
Joseph Lister
Note: In 1860’s , he used it to prevent surgical wound infections.
6
Q
Who invented the process of pasteurization and discovered that micro-organisms causes fermentation and diseases?
A
Louis Pasteur
7
Q
Who was the person that discovered the bacteria that caused anthrax, septicaemia, tuberculosis and cholera?
A
Dr Robert Koch
8
Q
Who discovered penicillin?
A
Alexander Fleming
9
Q
Which microbe is acellular(not composed of cells)?
A
Viruses
10
Q
What are the types of micro-organisms?
A
Archaea
Bacteria
Eukarya
11
Q
Which microbes are prokaryotes?
A
Bacteria and Archaea
12
Q
Which microbes are eucaryotes?
A
Protists
Fungi
Plants
Animals
13
Q
What is the major characteristic that distinguish prokaryotes and eukaryotes?
A
The cell of prokaryotes lack nucleus whereas the cells of eukaryotes contain nucleus.
14
Q
What is a pathogen?
A
It is an organism that causes disease.
15
Q
The cell walls of bacteria contain _____________.
A
peptidoglycan
16
Q
What are the common shapes of bacteria?
A
- Spherical(Coccus)
- Rod-shaped(bacillus)
- Curved(Spirillum, spirochette or vibrio)
17
Q
What are photosynthetic bacteria?
A
These bacteria use energy derived from sunlight and fix carbon dioxide for growth.
18
Q
Give examples of photosynthetic bacteria?
A
- Oxygenic cyanobacteria
- Anoxygenic green sulphur
- Green non-sulphur bacteria
19
Q
What are non-photosynthetic bacteria?
A
These bacteria obtain their energy from organic or inorganic compounds in their environment.
20
Q
The cell wall of archaea contain _______________.
A
pseudopeptidoglycan
21
Q
Algae falls into which category of eukaryotes?
A
Protists(plant-like)
22
Q
The cell wall of algae cells are made up of ________ , a type of ____________ .
A
cellulose; carbohydrate
23
Q
Algae are _____________ organisms that extract energy from the sun and release oxygen and carbohydrates into their environment.
A
photosynthetic
24
Q
Which gel is derived from algae?
A
Agar
25
List some differences between prokaryotic cells and eukaryotic cells?
- PCs are very minute in size whereas ECs are fairly large in size.
- PCs have only a single chromosome whereas ECs have more than one chromosome present.
- Nucleolus absent in PCs whereas nucleolus present in ECs.
- Membrane bound organelles are absent in PCs whereas they are present in ECs.
- Cell division in PCs occurs by fission or budding(no mitosis) whereas cell division in ECs occurs by mitosis or meiosis.
26
What are gram-positive bacteria?
They are bacteria with thick cell walls that yield a positive result during a gram stain testing. (The bacterium's cell wall stained purple)
27
What are gram-negative bacteria?
They are bacteria that does not yield a positive result during gram stain testing resulting in a pink stain.
28
What are the characteristics of gram-positive bacteria?
- No outer membrane
- Complex cell wall
- Thick peptidoglycan layer
- Certain surface appendages
29
What are the characteristics of gram-negative bacteria?
- Outer lipid membrane
- Thin peptidoglycan layer
- Usually doesn't have teichoic acids
- Can have flagella or pili
30
Give some examples of gram-positive bacteria?
Staphylococcus
Streptococcus
Bacillus
Clostridia bacteria
31
Give some examples of gram-negative bacteria?
E.coli
Salmonella
Shigella
32
What are helminths?
They are multicellular parasitic worms.
Note: They are not technically micro-organisms as most are large enough to be seen without a microscope.
33
Why does helminths fall within the field of microbiology?
Because diseases caused by helminths involves microscopic eggs and larvae.
34
Give an example of a helminth?
Guinea worm(Dracunculus Medinensis)
35
When does an infection involving helminths typically occurs?
After a person drinks water containing water fleas infected by guinea-worm larvae.
36
Define mycology?
It is the study of fungi.
37
What are fungi?
They are a group of eukaryotic organisms with a diversity of morphological appearances depending on species.(Mostly molds and yeasts)
38
What are mycoses?
They are fungal infection.
39
Fungi are _______________ and their cell walls are usually made out of ________ rather than cellulose.
non-photosynthetic; chitin
40
What is the use of molds in the pharmaceutical industry?
To make penicillin and cyclosporine.
41
List some importance of fungi?
- Nutrition(Edible mushrooms)
- Industrial use
- Fermentation(Brewer's and Baker's yeast )
- Plant pathology
- Medical importance
42
Fungi are ____________ and can be unicellular or __________ .
eukaryotes; multicellular
43
Fungi are said to be heterotrophic, which means?
They use a wide variety of materials for nutrition.
44
What are the components that make up fungi cell wall?
- Chitin
- Glucans
- Mannans
- Complex polysaccharides
45
Fungi cell membrane consist of _________ rather than ___________ like bacterial cell membrane.
ergosterol; cholesterol
46
What is the function of ergosterol in fungi?
It is the site of action of anti-fungal drugs.(e.g amphotericin B and azole group)
47
How does reproduction(cell division) occurs in fungi?
Both sexual and asexual.
48
What is a hypha?
It is a long, branching filamentous structure that is one of the threads that make up the mycelium of a fungus.
Note: It is increased by apical growth.
49
What does the tangled mass of hypha in a fungus called?
Mycelium
50
What are fungi that forms mycelium called?
Molds or Filamentous fungi
51
Hypha may be ________ or ________ .
septate; non-septate
52
What is the difference between septate and aseptate hyphae?
Septate hyphae are composed of individual cells separated from one another by cell walls whereas aseptate hyphae have no cell walls in the individual cells and their nuclei are spread throughout the hypha.
53
What are the 4 group of morphologic classes that fungi are grouped into?
1) Molds
2) Yeasts
3) Dimorphic fungi
4) Yeast-like fungi
54
Describe molds?
They are multicellular organisms that are composed of branching filaments(hyphae) that has spores which are resistant resting or dormant cells.
Note:- Also known as filamentous fungi.
- Reproduction can be asexual or sexual.
55
Give some examples of molds?
Black mold
Black bread mold
Aspergillus niger
56
Describe yeasts?
- Yeasts are predominantly unicellular micro-organisms that are commonly oval but some are elongated or spherical.
- Yeasts have no flagella or other locomotory organelles seen in bactria.
57
How does yeasts reproduce?
By budding.(Asexual reproduction)
58
Give an example of a pathogenic yeast?
Cryptocoocus neoformans
59
Describe yeast-like fungus?
They are micro-organisms that grow partly as yeasts and partly as elongated cells resembling hyphae.
60
Yeast-like fungus forms what type of hyphae?
Pseudomycelium
61
Give one example of yeast-like fungus?
Candida albicans
62
What are dimorphic fungi?
-They are organisms that have the ability to switch between two morphologies during their lifecycle: yeasts and molds.
63
Which fungi causes the most systemic infections?
Dimorphic fungi
64
What are superficial mycoses?
They are surface infections limited to outermost layers of skin and hair.
Note:- No inflammatory response.
- Only cosmetic problems.
65
List the 4 types of mycoses?
Superficial mycoses
Cutaneous mycoses
Subcutaneous mycoses
Systemic mycoses
66
Give some examples of superficial mycoses?
Pityriasis versicolor
Tinea nigra
Piedra
67
What are cutaneous mycoses?
- They are fungal infections deeper into the epidermis and its integuments.
- Also called Dermatophytosis.
Note:- Cutaneous mycoses are classified based on location of infection.
68
Where is tinea pedis fungal infection located?
On the feet or between the toes.
69
Where is tinea corporis fungal infection located?
Between the fingers, in the wrinkles on the palm.
70
Where is tinea cruses fungal infection located?
Lesions on the hairy skin around the genitalia.
71
Where is tinea capitis fungal infection located?
Scalp and eyebrows.
72
Where is onychomycosis fungal infection located?
Nail bed(It is a chronic infection).
73
What are subcutaneous mycoses?
Infections involving dermis, subcutaneous tissue, muscles and fascia.
74
What are systemic mycoses?
Infections originating primarily in the lungs(acquired by inhalation) and spreading to other organs.
75
What are opportunistic mycoses?
This category includes infections in which fungi of no significance or low virulence infect humans with compromised immune system.
76
Describe protozoa?
They are microscopic, one celled organisms that can be free-living or parasitic in nature.
77
Protozoa can _________ in humans.
multiply
78
What is the transmission of human intestinal protozoa between human hosts?
Through an oral-fecal route.
79
How does insect vectors such as mosquitoes or sand fleas transmit protozoa to other humans?
Protozoa is transmitted in human blood or tissue through bites.
80
What are the modes of transmission of Enteric protozoa?
Food-Borne Transmission
Water-borne Transmission
Potable water
Wastewater and biosolids.
81
Give some general measures that are effective against most enteric protozoa?
Handwashing.
Use of adequately treated water.(E.g by boiling water for drinking)
Washing of fruits and vegetables.
82
What is Leishmaniasis?
- A disease cause by a protozoan that is passed from sand flies to humans.
- It is characterized by serious lesions in the skin, viscera and mucous membranes of host.
83
What are the 3 main forms of leishmaniasis?
Visceral (kala-azar)
Cutaneous (most common)
Mucocutaneous
84
What is the first stage in the life cycle of leishmaniasis?
- Leishmaniasis is transmitted by the bite of infected female phlebotomine sand flies.
- The sand flies inject the infective stage(promastigotes) from their proboscis during blood meals.
85
What is the second stage in the life cycle of leishmaniasis?
Promatigotes that reach puncture wound are phagocytized by macrophages and other types of mononuclear phagocytic cells.
86
What is the third stage in the life cycle of leishmaniasis?
Promastigotes transform in these cellls into the tissue stage of the parasite(amastigotes).
87
What is the fourth stage in the life cycle of leishmaniasis?
Amastigotes multiply by simple division and proceed to infect other mononuclear phagocytic cells.
88
What are stages fifth and sixth in the life cycle of leishmaniasis?
Sand flies become infected by ingesting infected cells during blood meals.
89
What is the seventh stage in the life cycle of leishmaniasis?
In sand flies, amastigotes transform into promastigotes in the gut.
90
What is the eighth stage in the life cycle of leishmaniasis?
Promastigotes divide in the gut and migrate to proboscis.
91
Give examples of some medically important protozoa?
Flagellates
Amoebae
Sporozoa
Cilliates
92
What are flagellates?
- Flagellates are protozoans that have one or more whip-like flagella and in some cases unduling membrane.
- Reproduction in flagellates is either sexual or asexual.
93
What are the uses of a flagellum?
For locomotion and sensation.
94
Give some examples of some flagellates?
Giardia intestinalis
Trichomonas vaginalis(STD)
Trypanosoma
Leishmania
95
What are amoebas?
- Amoebas are protozoans that are typically amoeboid.
| - They use pseudopodia or protoplastic flow to move.
96
Give examples of amoebas?
Entamoeba
Negleria
Acanthamoeba
97
What are sporozoa?
They are parasitic spore-forming protozoans that have a complex life cycle with sexual and asexual reproductive phases.
98
Give examples of intracellular parasites?
Cryptosporidium
Cyclospora
Toxoplasma
Malarial parasites
99
What are ciliates?
Ciliates are complex protozoa bearing cilia distributed in rows or patches with two kinds of nuclei in each cell.
100
Give an example of ciliate found in humans?
Balantidium coli
101
Describe viruses?
Viruses are acellular micro-organisms that consists of proteins and genetic material that are inert outside of a host organism.
102
How does a virus multiply and infect other hosts?
By incorporating themselves into a host cell and thus are able to co-opt the host's cellular mechanisms hence they multiply and infect other hosts.
103
Define a virus?
An infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscope and is able to multiply within the living cells of a host.
104
List the characteristics of viruses?
-Infectious, acellular pathogens.
-Obligate intracellular parasites with host and cell-type specificity.
-DNA or RNA genome (never both).
-Genome is surrounded by a protein capsid and, in some cases, a phospholipid membrane studded with
viral glycoproteins.
-Lack genes for many products needed for successful reproduction, requiring exploitation of host-cell
genomes to reproduce.
105
Viruses do not have ______ that divide; new viruses are assembled in the infected ________.
cells; host cell
106
What give viruses the ability to mutate and evolve?
Genes
107
Viruses are evolved from ________ or ________.
plasmids; bacteria
108
What shapes may viruses take?
Helical
| Icosahedral
109
Give some examples of some viruses?
Rhinovirus(common cold)
Influenza
Norovirus
Ebola
110
What viruses do after taking control of a host cell's genetic material?
They multiply.
111
List the viral components in viruses?
Nucleic acids
Capsid
Fat envelope
112
How does viral multiplication proceeds?
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Adsorption
Penetration
Uncoating
Synthesis
Assembly and release
Adsorption
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