WEEK 5: SS1 BIOLOGY THIRD TERM

 

       GROWTH OF MICRO-ORGANISMS

Micro-organisms' growth refers to an increase in population size, i.e, an increase in the number of cells. Microorganisms grow and multiply by binary fission. For example, a bacterium can divide every 20 minutes and this time interval is known as the doubling/generation time. This generation time depends on environmental factors like the availability of food, space, and adequate temperature.

BENEFICIAL EFFECTS OF MICRO-ORGANISMS

Many micro-organisms are beneficial in the following ways:

1. In nature, they function as decomposers and primary producers. Many saprophytic bacteria and fungi convert dead remains of organisms and their wastes into humus , which improves soil fertility.

2. In medicine, microbes are useful in the manufacture of drugs, vaccines and antibiotics which help in curing many human diseases e.g Penicillin - an antibiotic obtained from Penicillium notatum (a fungus). Also, sources of Vitamin B and Enzymes.

3. In Industries, microbes are useful for baking, alcohol fermentation, dairy, tobacco curing, leather tanning etc

HARMFUL EFFECTS OF MICROBES. Microorganisms are responsible for the following-

1. Cause of disease

2. Food spoilage

3. Deterioration of materials

4. Death

5. Product quality reduction

6. Crop and livestock yield reduction

DISEASES CAUSED BY MICRO-ORGANISMS

Some important diseases of humans are discussed in the table below:

Disease	Pathogen	Method of spread	Symptoms
Measles	Paramyxovirus	Air	Sharp cough, headache, rashes, fever
Amoebic dysentery	Entamoeba histolytica	Food and water contaminated with amoebic cyst and faeces	Heavy vomiting, diarrhea, abdominal pains
Malaria	Plasmodium species	Bite of infected Anopheles mosquito	Chills, fever, sweating, headache, loss of appetite, nausea
Rabies	Rhabdo virus (an RNA virus)	Breaks in the skin through bites of infected dogs, cats	High fever, headache, sore throat, convulsions

ASSESSMENT: 

1. State and describe the harmful effects of Micro-organisms.

2. Mention some examples of diseases caused by microbes, pathogen (causative organism), mode of transmission and symptoms

3. Describe STIs mentioning examples

ASSIGNMENT: Mention possible means of controlling harmful microbes.