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Micro MLAB122 check 121 for lecture 4 > Lecture 1 > Flashcards

Lecture 1 Flashcards

1
Q

What is Microbiology

A

study of microscopic organisms also known as microbes

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2
Q

four major groups of microorganisms(morgs)

A

Viruses
Bacteria
Fungi
Parasites(protozoa and metazoa)

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3
Q

Branches of Microbiology

A 
Industrial Microbiology
Agricultural Microbiology
Sanitary Micro
Veterinary Micro
Medical/Clinical  Micro
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4
Q

Medical microbiology

A

study, identification and the control of microbes which can cause disease in humans

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5
Q

microbes which can cause disease in humans

A

Pathogens

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6
Q

Illness caused by pathogens is termed

A

infection or infectious disease

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7
Q

four major disciplines:

A

Bacteriology: the study of bacteria
Mycology : the study of fungi
Parasitology : the study of parasites
Virology : the study of viruses

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8
Q

Viruses

A

Are non-cellular particles
They are the smallest ,ranging in size from 0.01 to 0.3 µm (10-300 nm) They are observed only through an electron microscope
May not be living
Consists of a genomic core of DNA or RNA but never both,and a coat of protein around the core known as envelope
Produce progreny in host
No independent reproduction
Obligate intracellular parasites

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9
Q

Bacteria:

A

They are prokaryotic microbes 2 to 6 µm in size.
Unicellular can reproduce independently by binary fission
Divide by fission- form colonies
Are able to live independently in nature, in the soil, water, on plants, animals and humans when live as companions with the humans known as Normal flora
When cause disease in humans known as pathogens
Most bacteria are free living or parasitic forms that can metabolize and reproduce by independent ways.

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10
Q

Fungi

A

They are eukaryotic 2.0 to 100 µm in size
They are unicellular and multicellular
Unicellular-Yeast
Multicellular- molds,dimorphic fungi (Pathogenic fungi) Candida ( opportunistic pathogens)
Have all organelles found in human cells

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11
Q

Protozoa

A

Most protozoa are single celled
They are eukaryotic
5.0 to 200 µm
They are motile by pseudopods ,flagella or cilia.
Are free living or live inside the human body for part of their life cycle
E.g amoeba

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12
Q

General size of microorganisms

A 
Amoeba  = 15 µm
Yeast       =   5 µm
Bacteria    = 2 µm
Virus          = 0.1 µm( 100 nm)
So,
amoeba >yeast>bacteria>virus
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13
Q

Unusual forms of medically significant bacteria

A

Rickettsias, Chlamydias, Spirochetes
The rickettsias and chlamydias, however have adapted to life inside their host cells.
Eg.Chlamydia tracomatis

Therefore, are considered obligate intracellular parasites

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14
Q

capsule:

A

it is a slime layer found in some bacteria outside the cell wall, not easily washed off, and,
Allows these microbes to resist phagocytosis by WBCs and increases the virulence (disease causing capacity ) eg.E.coli, Klabsiella pnemoniae,Haemophilus influenza

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15
Q

Cell wall

A

it is a unique prokaryotic feature, resists shrinkage of the cell.
Bacterial cell walls gain their rigidity from a unique macromolecule called peptidoglycan.
one of the major basis for the classification of the bacteria. Gram positive and Gram negative cell walls are chemically different

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16
Q

Cell membrane

A

it is a semi-permiable organelle ,which allows material in and out of the cell

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17
Q

Flagella

A

they are whip like hairs/tails helps in the motility of the bacterium

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18
Q

Pili/Fimbriae

A

are small hair like projections on the surface, allow bacteria to stick to the surface and also used to
move DNA plasmids between bacteria

19
Q

Plasmid

A

It is a DNA molecule that is separate from, and can replicate independently of, the chromosomal DNA.
They are double-stranded and, in many cases, circular. Plasmids usually occur naturally in bacteria.
Plasmids are responsible for the antibiotic resistance .

20
Q

Bacterial growth

A

Growth is the term applied to the process of increasing the number of bacteria.
Bacteria grown in the lab are referred to as a culture

21
Q

Conditions for growth

A

Temperature,moisture osmotic pressure,pH,nutrition (food) and gases

22
Q

Temperature

A

Bacteria can grow over a wide range of temperature and can survive in the range of -20 to 90oC.
However, for most pathogens 35-37 oC is the optimal temperature.

23
Q

Cryophiles

A

temp range -2 to 4 oC

24
Q

Psychrotrophs

A

temp range 20 -30 oC

25
Q

Mesophiles

A

temp range 25-40 oC

26
Q

Thermophiles

A

temp range 55-70 oC

27
Q

Hyperthermophiles

A

temp range 70 oC or greater

28
Q

Moisture

A

Moisture in the form of water and damper conditions favor bacterial growth. Dryness slows down the growth

29
Q

Osmotic pressure:

A

this is controlled by the amount of solute (normally salt )in the environment. Too much of salt stops the growth. However some organism can grow in higher concentrations of salt

30
Q

pH

A

bacteria can grow over a wide range of pH between 3 to 9
pH 2 to 4.5 is acidic
pH 7to 7.4 is neutral this is the ph of blood
pH 8 to 10 is alkaline
Most bacteria can grow in the range of pH 5 o 8,optimum being pH 7 to 7.5

31
Q

Nutrients

A

Main nutritional requirement are in the form of
Water
Proteins
Essential elements in the form of C,H,O,N,P,S ,and,
Some other trace elements
Medium is a form of providing all the required nutrients to the microbe in an artificial environment

32
Q

Gases

A

Mainly oxygen and carbon dioxide

33
Q

Obligate aerobes

A

Certain bacteria have an absolute or obligate requirement of oxygen are called Obligate aerobes Eg Micrococcus species,Bacillus species
growth in a tube would be at the top
enzymes such as catalase and superoxide dismutase allow toxic oxygen to be neutralized

34
Q

Obligate anaerobes

A

Certain bacteria can grow in the absence of oxygen and are called Obligate anaerobes
eg- Clostridium species
Growth in a tube at the bottom
lacks the enzymes to neutralize harmful forms of O2

35
Q

Facultative Anaerobes

A

Some bacteria grow better in the presence of O2 but can also grow without it they are called Facultative Anaerobes eg. E.coli
Growth in the top of the tube and then a little bit throughout
enzymes such as catalase and superoxide dismutase allow toxic oxygen to be neutralize

36
Q

Microaerophiles

A

Bacteria able to grow in a little amount of oxygen (i.e lower than atmospheric oxygen)are called Microaerophiles eg:Helicobacter pylori
growth in tube in the middle
produce lethal amounts of O2 if exposed to normal atmospheric oxygen

Certain microaerophiles can survive only if the carbon dioxide levels are high ,these are called capnophiles

37
Q

Aerotolerant anaerobes

A

only anerobic growth , but continues in prosence of oxygen
growth in tubes in clumps evenly
only presence of superoxide dimutase , o2 is partially neutralized . tolerates O2
Clostridium perfingens

38
Q

What is a medium

A

form of providing all the required nutrients to the microbe in an artificial environment .
individual components or by using dehydrated powder (basal medium) - more consistent prep.

39
Q

Shapes of bacteria

A

Coccus - round
Bacillus - rod - can be branched
Spiral bacteria -

40
Q

Gram postive

A

retain crystal violet and appear blue - purple

41
Q

Gram negative

A

do not retain the crystal and stain pink red

42
Q

Fastiidous bacteria

A

only grow on specialized medium

43
Q

What are two morphological forms of fungi

A

mold (reproduce by spores) and yeast(reproduce by budding and not spores)

44
Q

dimorphic fungi

A

Pathogenic fungi can grow in both yeast and mold forms, depending on culture conditions

Micro MLAB122 check 121 for lecture 4 (8 decks)

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