MICRO ORGANISMS: GROWTH, DISEASES, BENEFITS & HARMFUL EFFECTS

Bacteria reproduce by binary fission in which a single cell divides into two. This process is called asexual reproduction. The time interval required for the cell to divide into two is called generation time. This time varies from one organism to another. It strongly depends upon nutrient availability, temperature, gaseous requirement and pH. There are different phases in the growth of bacteria.

 

These include the (i) lag phase (ii) logarithmic or exponential phase (iii) the stationary  phase and (iv) decline or death.  The growth of micro-organisms can be measured by using any of these methods:

• Turbidity method.
• Serial dilution
• Squared transparent paper or cellophane

 

EVALUATION

1. State four factors that can affect the growth of
2. List three ways of measuring the growth of bacteria.

 

BENEFICIAL AND HARMFUL EFFECTS OF MICRO-ORGANISMS

BENEFICIAL EFFECTS

1. Bacteria help to digest cellulose in herbivores.
2. In man, they synthesize vitamin K and B₁₂
3. Bacteria and fungi are widely used in the synthesis of antibiotics
4. They are used to manufacture amino acids and vinegar
5. Bacteria are used to process milk into different tastes and flavours
6. They are used to decompose sewage into harmless inorganic compounds.
7. Microbial cultures are used to produce enzymes
8. Yeast is used as a leavening agent in baking industries.
9. Algae play important role in fertilizing the soil.
10. Bacteria are used to produce single-cells protein (SCP).

 

HARMFUL EFFECTS

1. Bacteria cause decay and spoilage of food items.
2. Materials like wood, paper, textiles, rubber and metals are destroyed by microbes.
3. They cause diseases of different types.

 

EVALUATION

1. State thee beneficial and three harmful effects of microorganisms.
2. Mention five mention five beneficial and five harmful microorganisms.

 

DISEASES CAUSED BY MICRO-ORGANISMS

 

DISEASE	CAUSATIVE AGENT	SYMPTOMS	TRANSMISSION	CONTROL
Chickenpox	Varicella Virus	Fever, tiredness, and an itchy, blistery rash.	Contact	Isolate patient and use appropriate drugs.
Cholera	Vibrio Cholerae	·         Watery diarrhea, vomiting, leg cramps.	flies, food , faeces, carriers	Personal hygiene.
Common Cold	Rhino Virus	Cough, runny nose, shivering, etc.	Contact	Take appropriate medications and avoid contact.
Dengue	Dengue Virus (arbovirus)	Severe headache, severe eye pain (behind eyes), joint pain, muscle and/or bone pain, rash, mild bleeding (e.g., nose or gum bleed, petechiae, or easy bruising),low white cell count.	Aedes Mosquito	Drain the water and clear the bushes around.
Diarrhoea	Giardia intestinalis	Frequent passing of watery faeces, cramps and pains in the abdomen (stomach), nausea and vomiting.	contaminated stools	Personal hygiene
Diphtheria	Corynebacteriumdiptheriae (Bacteria)	A sore throat, hoarseness, painful swallowing, swollen glands (enlarged lymph nodes) in your neck, thick, difficulty breathing or rapid breathing, nasal discharge, fever and chills, & malaise.	Contact	Use antibiotics and avoid contacts.
Leprosy	Mycobacterium leprae	Disfiguring skin sores, lumps, or bumps (that do not go away after several weeks or months), loss of feeling in the arms and legs, muscle weakness.	Long and close contact	Use antibiotics and avoid contacts. Patients should be isolated.
Measles	Measles virus (ParaMyxoVirus)	A high temperature, sore eyes (conjunctivitis), runny nose, small white spots, harsh dry cough, going off food, tiredness, aches, pains, diarrhoea and/or vomiting.	Contact	Take appropriate medication and avoid contact.
Pneumonia	Diplococcus pneumonia	High fever, shaking chills, cough with phlegm (a slimy substance) which doesn’t improve or worsens, shortness of breath, chest pain when you breathe or cough, suddenly feeling worse after a cold, etc.	bacteria transmission by contact.	Use of antibiotics and avoidance of contact.
Poliomyelitis	Polio Virus or Enterovirus	Fever, sore throat, headache, vomiting, fatigue, back pain or stiffness, neck pain or stiffness, pain or stiffness in the arms or legs, muscle weakness or tenderness, & meningitis.	houseflies, food and water	Good hygiene and appropriate medication.
Rabies	Rhabdovirus	Fever, cough, sore throat, etc.	mad dog bites	Treat dogs and seek urgent medical attention in cases of bites.
Septic Sore Throat	Streptococcus Bacteria	Fever, nasal drainage, sore throat, swollen glands, difficulty swallowing, and irritability.	Contact	Use of antibiotics and avoidance of contact.
Sleeping Sickness	TryponosomaBrucei	·         Anxiety, drowsiness during the day, fever, headache, ·         insomnia at night, mood changes, sleepiness, ·         sweating, swollen lymph nodes all over the body, ·         swollen, red, painful nodule at site of fly bite.	reaches lymph nodes via transmission thru fly bites	Clear vegetations around, use insecticides and take appropriate medication.
Smallpox	Variola Virus	High fever, vomiting, fatigue, backache, a raised spotted rash, etc.	Contact	Take appropriate medication and avoid contact.
Tuberculosis	Mycobacterium tuberculosis	Malaise, weight loss, and night sweats.	Bacteria transmission by cough	Isolate patients and use appropriate antibiotics.
Tetanus	Clostridium tetani	Muscle spasms and breathing problems.	bacteria in soil thru wounds	Treat wounds urgently.
Typhoid	Salmonella Typhi	·         Abdominal tenderness, ·         agitation, bloody stools, chills,confusion, difficulty paying attention, fluctuating mood,nosebleeds,severe fatigue,weakness, etc.	Flies, food etc.	Treat water before drinking. Maintain personal hygiene. Use appropriate antibiotics.
Whooping cough	Hameophilius Pertussis	Cough, whooping sound during breathing, etc.	coughing and sneezing	Isolate patients and use appropriate antibiotics.
Influenza Flu	Orthomixovirus	fever and muscle aches, cold, runny nose, sore throat, etc.	Contact	Take appropriate medication and avoid contact.
Malaria	Plasmodium	chills, headache,muscle aches, tiredness, nausea, vomiting and diarrhea.	Bite from female Anophelex mosquitoes	Use of drugs, insecticides, etc.

 

EVALUATION

1. State the causative organisms, symptoms and control of the following diseases (i) Malaria     (ii) Cholera     (iii) Tuberculosis     (iv) Measles     (v) Poliomyelities
2. List five airborne and waterborne microorganisms respectively.

 

GENERAL EVALUATION

1. Mention the observable phases in the growth of microbes.
2. State five uses of microorganisms in industries.
3. Outline four general ways of controlling microorganisms.
4. Mention three microorganisms each that are involved in Nitrogen and Carbon cycle.
5. State three uses of microorganisms in (i) Agriculture     (i) Medicine
6. Describe three ways of measuring growth of bacteria.
7. List five ways through which microorganisms can be

 

WEEKEND ASSIGNMENT

1. The growth phase in bacteria in which cells divide steadily at a constant rate is called (a) Exponential phase     (b) lag phase      (c) stationary phase     (d) decline phase
2. Which of the following microbes causes cholera? (a) Virus    (b)Bacterium            (c) Protozoan    (d) Fungus
3. Growth of micro-organisms can be measured by the following methods except___________ method (a) serial dilution    (b) turbidity    (c) squared transparent paper      (d) dry weight
4. The following practices contribute to the control of the spread of diseases except (a) sewage treatment with chemicals       (b) proper sewage disposal    (c) disinfecting the surrounding       (d) using human faeces as manure
5. The vector of the trypanosome parasite is (a) housefly  (b) tse-tse fly   (c) mosquito     (d) black fly

 

THEORY

1. Define the following phases in microorganisms growth (i) lag    (ii) exponential     (iii) stationary.
2. State four ways in which each of the following organisms are beneficial to humans. Bacteria        ii. Fungi

 

See also

MICRO-ORGANISMS

BALANCE IN NATURE AND FAMILY PANNING

ECOLOGICAL SUCCESSION

POLLINATION

REPRODUCTIVE SYSTEM IN PLANTS