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MICRO ORGANISMS
LEARNING INTENTIONS
• Basic structure and characteristics of viruses, bacteria,
protists and fungi
• Their roles in maintaining balance in the environment and
web of life
• Symbiotic relationships between nitrogen-fixing bacteria
and plants, and Escherichia coli in the human intestine
• The effects and management of diseases caused by
micro-organism
• The use of drugs such as antibiotics on micro-organisms
PROPERTIES OF LIFE
1. Cellular respiration
2. Reproduction
3. Nutrition
4. Excretion
5. Locomotion and movement
6. Sensitivity and responsiveness
7. Growth and development
BIODIVERSITY OF MICRO-ORGANISMS
• Living organisms occur in different
shapes and sizes
• Scientists have found it convenient
to classify all these organism in to
the following kingdoms
A. Monera
B. Protista
C. Fungi
D. Plantae
E. Animalia
MICRO-ORGANISMS: ARE SO SMALL THAT THEY
CANNOT BE SEEN WITHOUT USING A MICROSCOPE
• Micro-organisms are found in all five
kingdoms (both good and bad)
• Micro-organisms are also found in a sixth
group which cannot be placed in any of the
five kingdoms. These micro-organisms are
called viruses
• Note that all the organisms in any kingdom
are not identical in structure or the way in
which they live
VIRUSES
• Cannot be placed in any of the five
kingdoms of living organism, because
they show characteristics of both non-
living things as well as some
characteristics of living organism.
• Can you remember the properties of
life?
PROPERTIES OF LIFE
1. Cellular respiration
2. Reproduction
3. Nutrition
4. Excretion
5. Locomotion and movement
6. Sensitivity and responsiveness
7. Growth and development
BASIC STRUCTURE OF VIRUSES
• Viruses come in different shapes and
sizes, but have the same basic structure.
• They are very small.
• A virus consists of a central core of nucleic
acid (DNA or RNA) covered by a protein
coat (capsid)
• Viruses that attack bacteria and plants
contain RNA only
• Those that attack animals may have either
DNA or RNA
• They are considered to be non-cellular or
acellular
HIV
Influenza virus
CHARACTERISTICS OF VIRUSES
• Viruses are parasites living in plants,
animals or bacteria (inactive in water,
air, soil)
• They are very specific with regard to
their host
• Viruses are extremely small
• Viruses are pathogens because they
need the host cell to replicate
• They have the ability to assemble
themselves within the host cell
DIAGRAM
VIRUSES – MAINTAINING A HEALTHY ENVIRONMENT
• CONTROL MANY ECOLOGICAL PROCESSES SUCH AS NUTRIENT CYCLING,
BACTERIAL AND ALGAL BIODIVERSITY AND ALGAL BLOOM CONTROL
• SCIENTISTS HAVE RECENTLY DISCOVERED THAT THERE ARE MANY VIRUSES
FOUND IN THE OCEAN. WHEN SEA-ORGANISMS DIE FROM A VIRAL
INFECTION THEIR BODIES PROVIDE NUTRIENTS TO BACTERIA IN THE DEEPER
PARTS OF THE OCEAN
• VIRUSES ARE PATHOGENS AND CAUSE MANY DISEASES IN PLANTS, ANIMALS
AND HUMANS.
• DISEASE HELP CONTROL THE NUMBERS OF DOMINANT HOST SPECIES
DISEASESEFFECT AND MANAGEMENT OF DISEASES CAUSED BY
VIRUSES
RABIES
• CAUSED BY THE RABIES VIRUS
• PRESENT ON EVERY CONTINENT EXCEPT AUSTRALIA AND
ANTARCTICA
• ONCE SYMPTOMS DEVELOP RABIES IS FATAL
• SPREADS THROUGH THE CENTRAL NERVOUS SYSTEM AND CAUSES
FATAL INFLAMMATION OF THE BRAIN AND SPINAL CORD
• TWO TYPES: FURIOUS AND PARALYTIC
RABIES VIRUS: CAUSED BY A VIRUS WHICH ATTACKS
DOMESTIC AND WILD ANIMALS, IT IS TRANSMITTED TO HUMANS BY A BITE OF AN INFECTED ANIMAL (SALIVA)
EFFECTS ON HUMANS
• AN INCUBATION PERIOD OF 1 TO 60 DAYS MAY OCCUR
• ONSET OF THE ILLNESS MAY OCCUR AFTER THE INCUBATION
PERIOD. SYMPTOMS THAT MAY OCCUR INCLUDE HEADACHES,
FEVER, SORE THROAT, NAUSEA, DIARRHOEA AND FATIGUE.
• DURING THE ACUTE NEUROLOGICAL OR AGITATION PHASE, THE
INFECTED PERSON MAY RUN ABOUT, UNDERGO CONVULSIVE
SEIZURES, PRODUCE LARGE AMOUNTS OF SALIVA, SHOW A FEAR
OF WATER AND HAVE A DIFFICULTY IN SWALLOWING AND
BREATHING.
• DEATH MAY OCCUR DUE TO HEART FAILURE AND BREATHING
DIFFICULTIES OR SEIZURES.
VACCINATIONS
• PREVENTION IS BETTER THAN CURE: VACCINATE ANIMALS
• PEOPLE WHO WORK WITH ANIMALS SHOULD BE IMMUNIZED BY
TAKING A VACCINE AGAINST THE RABIES VIRUS
• THEY SHOULD ALSO WEAR PROTECTIVE CLOTHING WHEN
WORKING WITH ANIMALS
TREATMENT ON EXPOSURE
• PERSONS EXPOSED TO THE RABIES VIRUS BY BEING BITTEN OR SCRATCHED
BY A RABID ANIMAL SHOULD BE TREATED IMMEDIATELY BY A QUALIFIED
MEDICAL PRACTITIONER.
• BY WASHING THE WOUND THOROUGHLY AND A COURSE OF
VACCINATION
• ONCE A PERSON SHOWS SIGNS OF THE DISEASE, THERE IS NO EFFECTIVE
TREATMENT.
OTHER RABIES SLIDES
HIV / AIDS (VIRUS)
• HIV (HUMAN IMMUNODEFICIENCY VIRUS) CAUSES AIDS (ACQUIRED
IMMUNE DEFICIENCY SYNDROME)
• IT IS A VIRAL DISEASE THAT ATTACKS THE BODY’S IMMUNE SYSTEM
• PATIENTS INFECTED WITH HIV DO NOT HAVE RESISTANCE TO
INFECTIONS AND CAN EASILY DIE FROM INFECTIONS OR MILD
DISEASES
• BODY FLUIDS SUCH AS BLOOD, SEMEN AND VAGINAL FLUID TRANSFER
HIV FROM ONE PERSON TO THE NEXT, INFECTED NEEDLES, BLOOD
TRANSFUSIONS, PREGNANCY AND CHILD BIRTH ARE ALSO WAYS HIV
CAN SPREAD AMONGST PEOPLE
• SYMPTOMS OF THE DISEASE DO NOT NECESSARILY DEVELOP 5 – 7
YEARS AFTER THE PERSON 1ST GOT INFECTED.
• HOWEVER PEOPLE ARE INFECTIOUS FROM THE MOMENT THEY GET
HIV
• HIV IS A RNA RETROVIRUS
• SIGNS AND SYMPTOMS
• ABOUT 50% OF PEOPLE INFECTED WITH HIV WILL SHOW FLU-LIKE
SYMPTOMS AROUND 6 WEEKS AFTER INFECTION
• THE REST HAVE NO SYMPTOMS
• ONSET OF AIDS OCCURS ONCE THE IMMUNE SYSTEM IS NO LONGER
ABLE TO FIGHT OFF INFECTIONS
• COMMON OPPORTUNISTIC INFECTIONS INCLUDE TB, ORAL THRUSH,
MENINGITIS, CHRONIC DIARRHOEA AND WASTING
• EFFECTS OF HIV / AIDS ON THE BODY
• HIV DAMAGES THE BODY’S IMMUNE SYSTEM
• IN HEALTHY PEOPLE SPECIAL WHITE BLOOD CELLS CALLED T4 CELLS (LYMPHOCYTES)
START FIGHTING AGAINST ANY VIRUS OR BACTERIUM THAT INVADES THE BODY
• IN PEOPLE INFECTED WITH HIV THE VIRUS ATTACKS THE T4 CELLS THE BODY CANNOT
PROTECT ITSELF AGAINST BACTERIA AND VIRUSES AND THE PATIENT IS EXPOSED TO
OPPORTUNISTIC INFECTIONS
• HIV RECOGNISES T4 CELLS BECAUSE THE PROTEINS ON THE SURFACE OF THE HIV FIT
EXACTLY INTO THE PROTEIN ON THE SURFACE OF CD4T CELLS.
• HIV SLOWLY DAMAGES THE IMMUNE SYSTEM FOR MANY YEARS AFTER IT HAS
INFECTED THE BODY.
• ONCE THE IMMUNE SYSTEM IS DAMAGED PEOPLE GET MILD SYMPTOMS SUCH AS
SKIN RASHES, FATIGUE, WEIGHT LOSS, NIGHT SWEATS AND ORAL THRUSH
• AFTER THAT MORE SEVERE SYMPTOMS START OCCURRING SUCH AS PNEUMONIA AS
THE PERSONS IMMUNE SYSTEM IS NO LONGER ABLE TO FIGHT INFECTIONS.
• (WHEN YOUR CD4T COUNT GETS BELOW A CERTAIN POINT YOU ARE CLASSIFIED AS
HAVING AIDS AND NO LONGER HIV)
• MANAGEMENT OF HIV/AIDS
• YOU CAN GET AN HIV TEST FROM ANY PUBLIC CLINIC OR DOCTORS
SURGERY
• IF YOU GET A NEGATIVE RESULT IN THE FIRST SIX MONTHS, YOU
SHOULD PERHAPS GO FOR A SECOND TEST
• SHOULD YOU HAVE A POSITIVE RESULT A TRAINED COUNSELLOR WILL
GIVE YOU THE RESULT FOR EMOTIONAL SUPPORT AND TO EXPLAIN
THE PROCEDURES REQUIRED FROM HERE ON
• ANTIRETROVIRAL’S ARE MEDICINES THAT DOCTORS GIVE OUT TO
PREVENT THE VIRUS FROM REPLICATING. IN SA GIVE IT AS A
COMBINATION OF THREE DIFFERENT DRUGS: ZIDOVUDINE,
LAMIVUDINE AND NEVIRAPINE.
• EACH DRUG WORKS ON A DIFFERENT STEP OF THE HIV CYCLE.
• THE TREATMENT MUST BE TAKEN STRICTLY AS PRESCRIBED FOR THE
REST OF THE PERSONS LIFE
• THEY DO NOT CURE HIV BUT OFFER MANY BENEFITS
• MANAGEMENT OF HIV/AIDS
• AVOID CONTACT WITH CONTAMINATED BODY FLUIDS
• HIV-PREGNANT WOMEN RECEIVE ANTIRETROVIRAL DRUGS TO
PREVENT TRANSMISSION TO THEIR UNBORN CHILD
• ONCE INFECTED TRY TO STAY AS HEALTHY AS POSSIBLE FOR AS LONG
AS POSSIBLE
• PROPHYLAXIS MAY BE OFFERED AGAINST TB AND OPPORTUNISTIC
INFECTIONS
• ANTIRETROVIRAL DRUGS DO NOT KILL THE VIRUS BUT PREVENT
FURTHER DESTRUCTION OF THE IMMUNE SYSTEM
• CLASSROOM ACTIVITY 14 PAGE 44
• INTERPRET DATA ON HIV / AIDS
BACTERIA • Bacteria are about 50 times larger than
viruses, but they are still the smallest
known living organisms.
• Bacteria are found everywhere (air, soil
and water)
• Bacteria prefer moisture and darkness
• The majority grow and reproduce best
when the temperature is between 30 and
37˚C
• They can survive at extremes of
temperature from -18˚ to 70˚C
BASIC STRUCTURE OF BACTERIA
• A Bacterium is made of
only one cell (unicellular)
• Bacteria are regarded as
prokaryotic organisms
(why?)
• Four main shapes of
bacteria occur coccus
(spherical cells), bacillus
(rod-like cells), spirillum
(spiral cells and vibrio
(comma-shaped cells)
BACTERIAL CELL (IRRESPECTIVE OF ITS SHAPE IT HAS THE FOLLOWING STRUCTURES)
• A cell wall (made up of peptidoglycan,
polysaccharides, proteins and lipids) occurs on
the outside
• Many bacteria cells also have a slime capsule
which protects the bacterium from drying out.
• Many bacteria also have whip-like flagella by
means of which they move in liquid
• Cytoplasm occurs within the cell wall
• No nucleus but chromatin network (nucleoid)
• Ribosomes occur within the cytoplasm, but there
are no mitochondria, plastids or endoplasmic
reticulum
BACTERIAL CELL (IRRESPECTIVE OF ITS SHAPE IT HAS THE FOLLOWING STRUCTURES)
• Fimbriae are involved in attachment
• Pili are involved in conjugation (transfer of DNA from one cell to
another)
• Cell membrane is a lipid bilayer (involved in many essential
processes)
CHARACTERISTICS OF BACTERIA
• Some bacteria are autotrophic
while others are heterotrophic
• There are two types of autotrophic
bacteria
A. Photosynthetic bacteria:
manufacture their own food using
light energy
B. Chemosynthetic bacteria:
manufacture their own food using
the energy released from
chemical processes
THERE ARE THREE TYPES OF HETEROTROPHIC BACTERIA
A. Parasitic bacteria: obtain food from
other living organisms on which they
live.
B. Saprotrophic bacteria: obtain food
from dead plant and animal material
C. Mutualistic bacteria: live in or on plants
and animals for the benefit of both
organisms
DIAGRAM
• HOMEWORK
BACTERIA
• BACTERIA PLAY AN IMPORTANT ROLE IN LIFE AND ARE INVOLVED IN
SYMBIOTIC RELATIONSHIPS
1. MUTUALISM: NITROGEN-FIXING BACTERIA USE NITROGEN FROM THE AIR
TO FORM AMMONIA. THESE BACTERIA LIVE IN ROOTS OF LEGUMINOUS
PLANTS. THE BACTERIA CONVERT THE AMMONIA INTO NITRATES. PLANTS
ABSORB THE NITRATES AND USE THEM IN METABOLIC PROCESSES.
BACTERIA HAS A PLACE TO LIVE AND PLANTS GET NUTRIENTS
BACTERIA
1. MUTUALISM: E. COLI IN THE LARGE INTESTINES IN HUMANS. THE BACTERIA
HAS A GOOD SUPPLY OF FOOD AND A GROWTH HABITAT, THE BACTERIA
PROVIDE HUMANS WITH VIT K WHICH ASSISTS IN THE ABSORPTION OF
NUTRIENTS
2. COMMENSALISM: THE BACTERIUM STAPHYLOCOCCUS EPIDERMIDIS IS
PRESENT ON HUMAN SKIN. THE BACTERIUM BENEFITS FROM HAVING A
HABITAT BUT IT DOES NOT HARM OUR SKIN
BACTERIA CONTINUED…
CONTINUED AGAIN…
• BACTERIA IN BIOTECHNOLOGY
• WE USE CERTAIN BACTERIA TO MAKE CERTAIN ANTIBIOTICS
• SOME SPECIES OF BACTERIA ARE ABLE TO DECOMPOSE SEWAGE WASTE
• CERTAIN SPECIES OF BACTERIA CAN DIGEST HYDROCARBONS IN PETROLEUM,
ENVIRONMENTALISTS USE THESE BACTERIA TO CLEAN UP OIL SPILLS
• SCIENTISTS USE BACTERIA AS BIOLOGICAL PEST CONTROL
• DAIRY FARMERS USE CERTAIN BACTERIA TO MAKE CHEESE AND YOGHURT,
CERTAIN INDUSTRIES ALSO USE BACTERIA TO MAKE VINEGAR
CHOLERA
• CAUSED BY THE BACTERIUM VIBRIO CHOLERAE WHEN WATER OR
FOOD CONTAMINATED BY FAECES IS SWALLOWED.
• IT AFFECTS THE ALIMENTARY CANAL, CAUSING SEVERE DIARRHOEA..
• IT IS LINKED TO INSUFFICIENT ACCESS TO SAFE WATER AND PROPER
SANITATION.
SYMPTOMS OF CHOLERA
• PROFUSE WATERY DIARRHOEA AND VOMITING
• DEHYDRATION AND LOSS OF ELECTROLYTES
• SYMPTOMS APPEAR 1-5 DAYS AFTER BEING INFECTED
• CAN LOSE 10-20L OF WATER A DAY AND CAN DIE OF
DEHYDRATION WITHIN HOURS OF SYMPTOMS STARTING
• THERE ARE ALSO DISEASE CARRIERS
EFFECTS OF CHOLERA
• ABOUT 75% OF PEOPLE INFECTED WITH CHOLERA DO NOT DEVELOP
ANY SYMPTOMS.
• THE PATHOGENIC BACTERIA STAY IN THEIR FAECES FOR 7 TO 14 DAYS
• ABOUT 25% OF PEOPLE INFECTED SHOW A SUDDEN ONSET OF ACUTE
WATERY DIARRHOEA THAT CAN LEAD TO DEATH BY SEVERE
DEHYDRATION.
• INDIVIDUALS WITH LOWER IMMUNITY, SUCH AS MALNOURISHED
CHILDREN OR PEOPLE LIVING WITH HIV, ARE AT GREATER RISK OF
DEATH IF INFECTED BY CHOLERA.
• IT IS SUCH A VIRULENT DISEASE THAT, IF LEFT UNTREATED, IT CAN EVEN
KILL HEALTHY ADULTS WITHIN A FEW HOURS.
MANAGEMENT OF CHOLERA
PREVENTION
• HEALTH EDUCATION, INCLUDING THE NEED TO WASH HANDS WITH SOAP AFTER DEFAECATION AND BEFORE
HANDLING FOOD.
• CLEAN WATER AND PROPER SANITATION FOR ALL SECTORS OF THE POPULATION IS EXTREMELY IMPORTANT.
• SEWAGE TREATMENT
TREATMENT
• ABOUT 80% OF PATIENTS CAN BE SUCCESSFULLY TREATED BY DRINKING A SOLUTION OF RE-HYDRATION SALTS
• IN VERY SERE CASES, LIQUIDS WITH RE-HYDRATION SALTS MAY HAVE TO BE GIVEN BY MEANS OF ‘DRIPS’.
• SOMETIMES, ANTIBIOTICS MAY BE GIVEN TO STOP DIARRHOEA.
TUBERCULOSIS (BACTERIA)
• TB IS AN INFECTIOUS DISEASE CAUSED BY THE BACTERIUM
MYCOBACTERIUM TUBERCULOSIS.
• TB CAUSES ABOUT 4-8 MILLION DEATHS EACH YEAR WORLD WIDE
• THE EFFECTS OF TB ON THE BODY
TB USUALLY AFFECTS THE LUNGS WHERE IT CAN EITHER BE DORMANT OR GROW
AND REPRODUCE. HOWEVER IT CAN AFFECT ALMOST ANY PART OF THE BODY. AT
FIRST THE PATIENTS MAY NOT EVEN NOTICE THE SYMPTOMS.
THE BACTERIA USUALLY GROW IN THE LUNGS, DESTROYING THE LUNG TISSUE.
THE SYMPTOMS INCLUDE:
1. A PERSISTENT COUGH THAT USUALLY LASTS MORE THAN 3 WEEKS
2. NIGHT SWEATS FOR WEEKS OR MONTHS
3. WEIGHT LOSS
4. FATIGUE
5. HIGH TEMPERATURE
6. SHORTNESS OF BREATH
7. BLOOD WHEN COUGHING
• MANAGEMENT OF TB
THERE ARE METHODS FOR TREATING TB AND PREVENT GETTING TB. THESE
METHODS ARE:
1. VACCINATIONS
• CAN PROVIDE US WITH ACTIVE AND PASSIVE COMMUNITY WHICH MAKES US
IMMUNE TO THE DISEASE
• DOCTORS GIVE 6 WEEK OLD BABIES THE BCG VACCINATION TO TRY TO
PREVENT INFECTION BY TB BACTERIA
2. ANTIBIOTICS
• A PERSON INFECTED CAN TAKE AN ANTIBIOTIC-COCKTAIL WHICH IS MADE UP
OF THREE ANTIBIOTICS.
• PATIENTS MUST TAKE THESE ANTIBIOTICS FOR 6 MONTHS. IF THEY D O NOT
TAKE ALL THEIR MEDICINES, THE BACTERIA CAN MATURE QUICKLY AND BECOME
RESISTANT TO THE ANTIBIOTICS. RECENTLY IN SA A NEW ANTIBIOTIC-RESISTANT
STRAIN IF TB CALLED XDR TB (EXTENSIVELY DRUG RESISTANT TUBERCULOSIS)
DEVELOPED. THIS HAPPENS AS A RESULT OF PATIENTS NOT COMPLETING THEIR
TREATMENT
• THE TREATMENT HAS MANY UNPLEASANT SIDE-EFFECTS
-
PROTISTA
• Protists consist of three main groups
1. Animal-like protists
2. Plant-like protists
3. Algae
• Protists are all eukaryotes
• They are micro-organisms that are
simple in structure
• Most are unicellular although some are
multicellular with no specialised tissues
• They range from microscopic organisms
to huge tree-like structures.
DIAGRAMS
PROTISTS
• FORM THE BASIS OF MANY FOOD CHAINS
• ENVIRONMENTAL ROLE
• GREEN ALGAE CAN PHOTOSYNTHESIZE AND PRODUCE OXYGEN – AQUATICS
USE THIS OXYGEN TO SURVIVE
• PHYTOPLANKTON CONSIST OF ALGAE AND DIATOM SPECIES. THEY FORM THE
BASIS OF THE FOOD CHAIN IN AQUATIC ENVIRONMENTS. THEY
PHOTOSYNTHESIZE AND PRODUCE CARBOHYDRATES. AQUATIC ORGANISMS
USE THESE CARBOHYDRATES AS A FOOD SOURCE
• SOME PROTISTA ARE PREDATORS (EG: AMOEBA) SO THEY ARE IMPORTANT
PRIMARY CONSUMERS IN THE FOOD CHAIN.
• FOOD: SEAWEEDS – BEEN EATEN BY HUMANS FOR YEARS
PROTISTA CONTINUED…• FERTILIZERS
• INDUSTRY
• MEDICINES
• DISEASES
• SOME PARASITIC PROTISTS ARE PATHOGENS SUCH AS
• TRYPANASOMA GAMBIENS CAUSES AFRICAN SLEEPING SICKNESS
• PLASMODIUM VIVAX AND PLASMODIUM FALCIPARUM WHICH CAUSES MALARIA
• MANY OF THESE PATHOGENS HAVE A BIG ECOLOGICAL IMPACT WHEN THEY
CAUSE THE DEATH OF ANIMALS
MALARIA (PROTISTS)
• PLASMODIUM IS THE MALARIA PARASITE
• IT IS A PROTISTA THAT LIVES IN THE BLOOD STREAM AND LIVER OF
HUMANS INFECTED BY THE PARASITE.
• THE FEMALE ANOPHELES MOSQUITO IS THE DISEASE VECTOR. THE
MOSQUITO TRANSMITS THE MALARIA PARASITE BY SUCKING BLOOD
FROM HUMANS
• UNTIL 1999 IT WAS LISTED AS THE DISEASE THAT KILLS THE MOST
PEOPLE PER ANNUM (HIV / AIDS HAS TAKEN OVER)
• EACH YEAR BETWEEN 300 AND 500 MILLION CASES OF MALARIA ARE
REPORTED WORLD WIDE. BETWEEN 1.5 AND 2.7 MILLION PEOPLE DIE
FROM MALARIA EACH YEAR.
• MALARIA DISTRIBUTION IN THE WORLD
• EFFECTS OF MALARIA
THE INFECTED PERSON FEELS SYMPTOMS OF THE DISEASE WHEN THE
PLASMODIUM PARASITE LEAVES THE LIVER AND ENTERS THE RED
BLOOD CELLS.
WHEN THE RED BLOOD CELL BURST, THE PATIENTS TEMPERATURE
INCREASES AND CAN GO AS HIGH AS 40˚C.
DEVELOP FLU-LIKE SYMPTOMS
THIS STAGE OF THE DISEASE CAN BE VERY DANGEROUS AND MANY
PEOPLE DIE.
THE BURST BLOOD CELLS CAN BLOCK BLOOD VESSELS AND STOP
OXYGEN REACHING MANY PARTS OF THE BODY
• MANAGEMENT OF MALARIA
MALARIA IS A COMMUNITY DISEASE THAT AFFECTS A LARGE NUMBER OF PEOPLE
WE NEED A COMBINATION OF STRATEGIES TO TRY AND CONTROL THE DISEASE
MOST OF THE STRATEGIES ARE AIMED AT THE MOSQUITO EG.
o PREVENT THE MOSQUITO FROM BREEDING (NEED WATER TO LAY THEIR EGGS –
SPRAY LAKES WITH THIN LAYER OF OIL / INSECTICIDES)
o PREVENT MOSQUITO FROM BITING PEOPLE – MOSQUITO NETS AND FLY SCREENS
o USE MEDICINES TO KILL THE MALARIA PARASITE IN BLOOD STREAM AND LIVER
o TAKE PROPHYLACTIC MEDICATION TO PREVENT GETTING INFECTED.
PEOPLE CANNOT BE IMMUNIZED AGAINST MALARIA – SCIENTISTS ARE WORKING
AT FINDING A WAY
DDT IS A PESTICIDE THAT IS USED TO KILL THE INSECT BUT IT IS BAD FOR THE
ECOSYSTEM SO IT IS NO LONGER USED.
FUNGI
• Mushrooms, yeast, ringworms and the
moulds found on bread and fruit are
all examples of fungi.
• Fungi are divided into two groups:
unicellular and multicellular
• Did you know that the greenish mould
Penicillium notatum from which the
antibiotic penicillin is obtained, is also
a fungus?
BASIC STRUCTURE OF FUNGI
• Fungi have a unique cell wall structure
made up of chitin.
• All fungi do not have chlorophyll
• All fungi reproduce by means of spores
• Fungi are all eukaryotic
• Most fungi are filamentous (hyphae).
• Fungi reproduce both sexually and
asexually
• Although all fungi reproduce by spores,
fungi are not all the same in terms of
where these spores are produced. For
example
a. Bread mould produce their spores in
special spore cases called sporangia
b. Others e.g. Mushrooms produce their
spores in club-shaped structures which
are usually found within cap-like
fruiting bodies
c. Still others, produce spores in sac-like
structures e.g. Yeast and penicillium• CLASSROOM ACTIVITY 3
FUNGAL DISEASES AND DIAGRAM
FUNGI
• FUNGI ARE DECOMPOSERS AND RECYCLE NUTRIENTS
• FUNGI ARE IMPORTANT TO PEOPLE AS A SOURCE OF FOOD AND MEDICINE
• MUSHROOMS
• PENICILLIUM FUNGUS FOR THE ANTIBIOTIC PENICILLIN
• SYMBIOTIC RELATIONSHIPS
• MUTUALISM: LICHENS + MYCORRHIZA
• PARASITIC: CANDIDA ALBICANS – BENEFICIAL IN SMALL AMOUNTS BUT BAD IN
LARGE AMOUNTS
ATHLETES FOOT (FUNGI)
• ATHLETES FOOT IS A SKIN INFECTION CAUSED BY THE MICROSCOPIC TINEA
FUNGUS.
• PEOPLE OFTEN GET THE FUNGUS WALKING BAREFOOT IN PUBLIC SHOWERS
• GROW WITHIN THE DEAD LAYERS OF THE SKIN
• PEOPLE WHO ARE INFECTED WITH THE FUNGUS LEAVE SMALL PIECES OF THE
FUNGUS WHEN THEY WALK
• THE FUNGUS GROWS BETWEEN THE TOES AND CAUSES RED SCALY PATCHES
ON THE SKIN THAT ARE VERY ITCHY
• GOOD FOOT HYGIENE IS IMPORTANT – MAKE SURE SHOES ARE BIG ENOUGH,
CHANGE SOCKS EVERYDAY, WASH YOUR FEET REGULARLY WITH SOAP AND
WATER, AND DRY WELL.
• MAKE SURE PUBLIC SHOWERS ARE WASHED REGULARLY WITH DISINFECTANT
• RINGWORM
ATHLETE’S FOOT
ATHLETE’S FOOT
PLANT RUST (FUNGI)
• PLANT RUST ARE FUNGAL PARASITES THAT CAN DAMAGE A LARGE
NUMBER OF CROPS EG. PUCCINIA GRAMINIS INFECTS WHEAT
• THEY ALSO MAKE HOST PLANTS VULNERABLE TO OTHER DISEASES
• FARMERS CAN USE FUNGICIDE TO PREVENT FUNGAL INFECTIONS
OR TO CURE INFECTED PLANTS
• IF NOT TREATED THE PLANTS WILL DIE.
• RUSTS PRODUCE MILLIONS OF TINY SPORES
MANAGING RUSTS
• ROTATING CROPS TO STOP THE SPREAD OF THE DISEASE
• USING RUST-RESISTANT VARIETIES OF CROPS AND “DISEASE-FREE” SEEDS
• ALL EQUIPMENT SHOULD BE STERILISED
• NOT EXPOSING CROPS TO MOIST HUMID CONDITIONS FOR LONG PERIODS.
• BURNING INFECTED MATERIAL