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Microorganisms and Viruses
Microorganisms and Viruses
8.3
Microorganisms and Viruses
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.
Microorganisms and Viruses
8.3
Microorganisms and Viruses
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.
Chapter : Biodiversity
Topic : Microorganisms and Viruses
Form 5
Biology
View all notes for Biology Form 5
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Biodiversity
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Meristematic Tissues and Growth
Growth Curves
Leaf Structure
Main Organ for Gaseous Exchange
Main Organ for Transpiration
Main Organ for Photosynthesis
Compensation Point
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