the impact of microorganisms on life

7/28/2019 The Impact of Microorganisms on Life

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THE IMPACT OF

MICROORGANISMS ON LIFE


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BACTERIA

Unicellular organisms. Have a basic cell

structure (cell wall, plasma membrane,

cytoplasm and genetic materials that are not

surrounded by nuclear membrane).

Bacteria have cell walls made of peptidoglycan

(a polymer)

Certain bacteria form spores under

unfavorable conditions.


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Bacteria

The name of bacteria depends on the shape.

Bacillus (rod shape), Coccus(spherical), spiral

(spirilium), vibrio (coma).

Example:

Lactobacillus sp.


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Bacteria

Staphylococcusaureus Vibrio cholerae Spiral-shaped: spirilium


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EFFECTS OF ABIOTIC COMPONENTS

ON THE ACTIVITY OF

MICROORGANISM Example of abiotic components: concentration of

nutrients, pH, temperature, and light intensity

All microorganisms except virus need nutrientsand water for reproduction and growth

Each species has its own optimum pH and

temperature. (bacteria prefer alkaline conditionwhile fungi prefer acidic condition)

Most microorganisms are inactive at low

temperature


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EFFECTS OF ABIOTIC COMPONENTS

ON THE ACTIVITY OF

MICROORGANISM The optimum temperature for most microbes is

between 35oC to 40oC

Beyond 60oC, the growth of microorganisms isinhibited

The microorganisms and spores can be destroyedat temperature of about 121oC.

Light intensity affects the growth of microbes. Most microbes prefer dark places. However

photosynthetic microbes need light to producefood.


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THE ROLE OF USEFUL

MICROORGANISMS IN THE

ECOSYSTEM Decomposition: carried out by a group of

saprophytic bacteria and fungi.

Decomposers breakdown the dead remains ofplants and animals and waste products of

animals and release the nutrients into the soil.

Nitrogen cycle:


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Nitrogen Cycle

Nitrosomonas sp

Nitrobacter spRhizobium sp

Nostoc sp

Pseudomonas

aeruginosa

Micrococcus sp


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THE ROLE OF USEFUL

MICROORGANISMS IN THE

ECOSYSTEM Alimentary canals: in termites, ruminants,

microbes such as Trychonympha sp (protozoa)

produce cellulase to digest cellulose Digestive system in humans: bacteria

synthesise vitamin B12 and K. B12 is essential

for erythopoiesis while Vit. K is essential for

blood clotting.


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HARMFUL MICROBES

Harmful microbes are called pathogens

Mode of transmission: food & water, droplet

transmission, airborne transmission, vectors

and direct contact with infected patients.

Some diseases can be transmitted trough

body fluid such as blood, semen and mucus.


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CONTROLLING PATHOGENS

Antibiotics, Antifungal, Antiviral

Vaccines

Antiseptics (acriflavin and iodine) Disinfectants (formaldehyde, alcohol 70% and

carbolic acid.

the impact of microorganisms on life

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