Back

Microorganisms and Viruses

 
8.3 Microorganisms and Viruses
 
The image is an informative graphic titled ‘Introduction to Microorganism.’ It is divided into four sections, each numbered and containing text: 1. ‘Microorganisms are tiny organisms and not be seen with naked eyes.’ 2.’Microorganisms can only seen with the help of light or electron microscope.’ 3. ‘Microorganisms consists of bacteria, protozoa, fungi and algae.’4. ‘Microorganisms are much smaller particles that do not carry out reproduction and only can develop in host cell.’ At the bottom, there is a logo with the text ‘Pandai.’
 
The Main Characteristics of Microorganisms and Viruses
Bacteria
  • Unicellular organisms.
  • Have cell wall, plasma membrane and DNA which is not enclosed by a nuclear membrane.
  • Are heterotrophs or autotrophs.
  • Reproduced by binary fission and conjugation.
  • Form spores under unfavourable condition.
  • Examples: Escherichia sp coli., Lactobacillus sp.
Protozoa
  • Unicellular organisms.
  • Live in aquatic.
  • Have plasma membrane, nucleus and other membranous organelles.
  • Heterotrophs organisms.
  • Use cilia, pseudopodium and flagellum to move around.
  • Reproduce sexually or asexually.
  • Examples: Paramecium sp., Ameoba sp. and Plasmodium sp.
Algae
  • Unicellular organisms, non-fillamentaous and multicellular organisms.
  • Able to carry out photosynthesis as they have chloroplast.
  • The cell wall is made up of glycoprotein.
  • Do not have stems, leaves and roots.
  • Reproduce sexually or asexually.
  • Examples: Chlamydomonas sp. and Spirogyra sp.
Fungi
  • Unicellular organisms and multicellular organisms.
  • Has no chlorophyll.
  • Saprophytic or parasitic organisms.
  • Secrete extracellular enzymes to breakdown organic matter before they are absorbed.
  • Reproduce by binding or formation of spores.
  • Examples: Yeast, Mucor sp.
Viruses
  • Not microorganisms
  • The smallest size.
  • Can only be seen under an electron microscope.
  • Only consists of DNA or RNA covered by a protein coat.
  • Cannot reproduce outside the host cells.
  • All are parasites.
  • Can be crystallised outside host cells.
  • Examples: Bacteriophage, influenza virus and HIV.
 
The Role of Microorganisms
Microorganisms as Producers
  • Provide nutrients to primary consumers.
  • Main energy source in a food chain.
  • Examples:
    • Cyanobacteria.
    • Phytoplankton (algae).
Microorganisms as Decomposers
  • Decompose organic materials to reduce pollution by preventing accumulation of the organic waste remains.
  • Return nutrients to soil.
  • Examples: 
    • Saprophytic bacteria.
    • Fungi.
Microorganism as Symbionts
  • Tryconympha sp. in a alimentary canal of termites secretes cellulase to digest carbohydrate into glucose to be absorbed by the termites.
  • Human colon has symbiotic bacteria which syntheis vitamin B and vitamin K.
  • Examples:
    •  Tryconympha sp. (protozoa)
    • Lactobacillus sp.
Microorganisms as Parasites
  • As predator to form a balanced food chains.
  • Also as prey for other consumers.
  • Examples:
    • Some bacteria.
    • Fungi.
 
Pathogens
  • Definition: An organism which causes diseases.
  • For example:
    • Viruses.
    • Bacteria.
    • Protozoa.
    • Fungi.
 
Vectors
  • Definisi: An organisms which transmit pathogens and cause certain diseases.
  • Contoh:
    • Mosquito.
    • Flies.
    • Cockroaches.
    • Infected wild animals.
 
The Effects of Pathogens on Human Health
  • Pathogens disrupt the immunity system in many ways.
  • Viruses or bacteria cause sickness when they disturb cell functions or cause cell damage.
  • Some pathogens release toxins that could lead to paralysis or destroy metabolic activities in the body.
  • The table below shows the symptoms of disease caused by pathogens:
Pathogen Example of Disease Symptoms of Disease
Virus - Human papillomavirus (HPV)
  • Sexually transmitted disease.
  • Cervix cancer.
  • Other cancer
  • Warts on hand, leg, face and genital organ.
  • Irregular blood spotting after periods.
  • Prolonged and more menstruation than normal.
  • Postmenopausal bleeding.
  • Increased vaginal discharge.
Bacteria - Salmonella sp. 
  • Food poisoning.
  • Vomitting.
  • Diarrhea.
  • Abdominal cramps.
  • Headcahe.
Protozoa - Plasmodium sp.
  • Malaria.
  • Shrivel is followed by headache.
  • Skin becomes yellowish.
  • Anaemia.
Fungi - Tinea sp.
  • Ringworm. 
  • An erythematous patch with slightly scaly and small erythematous popules present at its periphery.
  • The patch will enlarge and with the presence of its central clearing, it will appear ring-like or annular.

 
 

 

 

 

 

The views expressed in the notes here are those of the contributor and don’t necessarily represent the views of Pandai.
Chapter : Biodiversity
Topic : Microorganisms and Viruses
Form 5 Biology
Related notes

Report this note
MY
EN