Microorganisms and Their Effects on Living Things

1.1 The Classification of Microorganisms

Microorganisms are tiny organisms which can only be seen under a microscope.

The characteristics include their appearance, shape, size, method of reproduction, nutrition and habitat

Microorganisms

Virus

Protozoa

Fungi Bacteria

Algae

VIRUSES Viruses are the smallest microorganisms Structure: consist of strands of nuclei

acid (DNA) They are 2 types of shape:

Helical Polyhedral

Viruses do not make their own food.

They obtain food from animals, plants and some bacteria

They are parasites

They attached to host cell.

Bacteria Microscopic organisms that can be

found everywhere Simplest single-celled organisms Bacteria are surrounded by tough cell

wall Cell wall support the cell and maintains

its shape

Bacteria have hundreds of pilli Pilli enable bacteria to stick to certain

surfaces Some bacteria also have a tail called

flagellum that help them to remove Shapes of bacteria

Spherical: cocci Long chain: streptococci Bunches of grapes: staphylococci

Comma shape: vibrios Spiral shape: spirilla

Some bacteria carry out photosynthesis, some live as parasites and some live as saprotrophs

Reproduce asexually: Binary fission budding

Fungi Various sizes Plant that do not have chlorophyll Various shapes such as filament and

sphere Reproduce through:

budding – yeast Spore formation - mucor

Live as parasite or saprophytes

Can be found in dark and damp places

Protozoa Various sizes ad shapes Unicellular animals Reproduce through binary fission Live as :

saprophytes : Amoeba and Paramecium Parasites : Plasmodium

Can be found in fresh water and damp places

Algae Various sizes and shapes Unicellular or multicellular Reproduce through binary fission Live as autotrophs Can be found in damp areas that

receive sunlight

Factors that affect the growth of microorganisms

Nutrition Temperature Humidity Light pH

Useful microorganisms

Use of microorgans

m

Digestion animals

food

Making bread

Purifying water

Making cheese

Making antibioti

cs

Disease caused by bacteria

Tuberculosis Cholera Gonorrhea syphilis

Tuberculosis

Caused by bacilli bacteria

Affect other organ such as lymph nodes, bones and joints

Symptoms: chest pain, fever, sweating at night, weight loss

Cholera

Caused by vibrios bacteria

Transmitted by water or food that has been contaminated with the faeces

Symptoms: diarrhoea, vomitting and fatigue

Gonorrhea

Sexual transmitted disease caused by cocci bacteria

(in 1 to 14 days after infection) burning sensation when urinating accompanied by some discharge

Syphilis

Sexual transmitted disease caused by spirilla bacteria

Red pimples, rashes, fever, headache, hair loss.

Disease caused by viruses

Common cold Dengue fever Hepatitis AIDS

Common cold

Caused by viral infection of the mucous membrane, air passage or lungs.

May spread to the ears, sinuses and eyes

Spread to the lung that cause bronchitis and pneumonia

Dengue fever

Caused by distinct virus carried by mosquitoes

Causes fever, efes aches, pain in the muscle and joints

Sometime causes very low blood pressure and weak pulse

AIDS

Caused by HIV viruses

Symptoms: tiredness, fever, loss of appetite and weight

Infected by pneumonia, tuberculosis, Kaposi’s sarcoma

Hepatitis

Disease of the liver

Caused by alcohol and drugs

Symptoms: urine become dark, jaundice.

Live failed to function

Disease caused by fungi Tinea Ringworm

Tinea

White spot on facial, body, hand and feet

Ringworm

Red area on the body

Skin become red and scaly

Disease caused by protozoa Malaria

Caused by Plasmodium Transmitted by female Anopheles

mospuito Fever with reach 410C Attack in 2 or more hours Symptoms: headache, muscle pain,

nausea and feeling chill