To Get this chapter, you must activate this app
Version: 1.0.2
Verification Number:
TT
Enter the Activation Number below:

To Get your activation number
Contact:

08033527655
+2348033527655
or
Notable Concepts
  1. Micro organisms around us
  2. Culture: A technique for growing micro organisms
  3. Identification of micro organnisms
  4. Micro organisms in our bodies and food
  5. Beneficiary and hormful effects of micro organisms
fig14.1: Plasmodium falciparum
fig14.2: bacterium
fig14.3: Influenza virus
Background information
Micro organisms are very minute living things which can not be seen individually by the human eyes. They are commonly called germs and microbes and they can be seen and studied with the aid of a microscope.
Micro organisms include all viruses, bluegreen algea, protists and certain fungi. They can be found in the air, water, soil, on surface of objects and within living organisms.
Culture: A Technique for growing micro organisms
Micro organisms can be grown in the laboratory in special media using the culture technique. The nutrient agar is used for culture of most bacteria. To culture organisms, the procedure of aseptic technique is applied so as not to contaminate the culture media with microbes from the surroundings or clothes or even the apparatus used.

Identification of micro organisms

Micro organisms can be identified by:
  1. observing their forms and structure through a microscope.
  2. Staining technique with various types of stains and observing their reaction through the microscope
  3. colony characteristics using various types of culture media,
  4. Their oxygen requirements especially bacteria
  5. Applying biochemical tests so as to identify the activities of micro organisms and identify it through that.

Micro organisms in our bodies and foods

Apart from the presence of micro organism in air, water, surface of objects and certain living things, micro organism exists in human body and food substances.
Micro organisms in the body include:
The normal microflora in the body, pathogenic micro organisms in the body,
Normal microflora start to colonize the body of infants few hours after birth. They prevent or interfere with the invasion of the body by pathogens by producing subtances which interfere with the survival or multiplication of certain pathogens. But microflora can become pathogens due to low resistance or due to a relocation or change in environment of the bacteria in the body.
Pathogenic micro organisms are the micro organisms that usually establish them selves in human bodies and cause diseases. Such can occur due to (I) low body resistance, disruption of normal microflora in the body by antibody therapy and delay in the establishment of normal microflora in infants.
Micro organisms have food as their ideal medium in which they grow and multiply. The characteristics of a given food determines the type of micro organisms that grow and multiply in it.
When food is contaminated, micro organisms multiply rapidly in it if the food is not cooked long enough to kill micro organisms, and their spores and to break down the toxins. Disease causing micro organisms are called disease vectors. The method, used by the disease vector in circulating the disease can be mechanically, biologically.

Beneficial effects of micro organisms

  1. Maintenance of soil fertility and recycling of nutrients in the ecosystem through their decomposing activities
  2. Micro organisms used in chemical processes lowers the operating cost of the process. Example: enzyme technology and genetic engineering.
  3. Biological control of pests and biodegradation of pollutants

General questions on micro organism around us

1. State the other three groups of living things apart from virus and bacteria in which micro organisms belong
2. Among the microorganisms, a is not capable ofgrowing on its own except in a living medium
3. In preparing a culture medium, technique is applied in orderto avoid microbial contamination.
4. Micro organisms that cause diseases in our bodies are called
5. Write four ways through which micro organisms can enter into the body of man
10. Animals that carry disease causing micro organisms are called
    Write four disease vectors you know
15. Bacteria is harmful to humans in two major ways.
16. The micro organism that is involved in alcoholic fermentation is and it belongs to the group of kingdom of living things called
17. Normal of the human body are micro organisms that colonize the body of human infants just a few hours after birth.
18. Female Anopheles mosquito is a vector of malaria fever while tsetse fly is a vector of
19. Cholera is a borne disease.
20. Virus, Rhizopus, plasmodium, tapeworm are micro organisms except

Expression Exercise

1a. Fill in the empty spaces in the table below using the example of number one
Disease Micro organisms that causes itThe disease vectorSymptoms and effects
i MalariaPlasmodium (protozoa) Female Anopheles mosquito Shivering high fever, with irregular bouts of sweating. high temperature, headache, vomiting, backache and jaundice
ii Yellow fever Arbovirus Aedes Mosquito High temperature, headache, vomiting, backache and jaundice
iii Sleeping sickness Trypanosoma (protozoa)Tsetse fly Persistent feeling of sleepiness fever and headaches
iv Cholera VibrocholeraHousefly Diarrhoea and vomiting
1b.
  1. State four different media through which pathogenic organisms can reach their animal hosts.
  2. Briefly explain three ways microorganisms can be useful in the food industries.
2a Write down the virus responsible for each of the disease listed below, the manner of attack ofthe disease and its method of spread
Disease Manner of attack Method of spread
Smallpox
Common cold
Rabies
HapatitisA
infective hapatitis
Acquired imune deficiency Syndrome or Aids.
2b Write four techniques that can be used to identify micro organisms
d. What micro organisms is responsible for the fermentation process.
Draw the organism
2. Obtain some pasteurized milk. Taste it and test its PH with a universal indicator paper. Take 10cm3 of the milk in a test tube and add 1cm3 drop of yoghurt. Test the PH of the pasteurized milk again if there is any little change in PH. Stopper the tube, incubate it at 370c for 24hours. Taste a sample of the milk again and check its PH again. Based on your observation answer the questions below.
1
  1. What type of taste did you observe in the milk before and after adding the yoghurt.
  2. b What was the PH of the milk before and after adding the yoghurt
  3. The yoghurt used contains a micro organisms called Lactobacillus. Is this organisms a bacteria or virus or fungi?
  4. d Write what was responsible for the taste you observed after adding the yoghurt.
2. a(i) (ii) state three ways in which bacteria are useful. (b) state three methods by which mosquitoes can be controlled and state the reason for each method.
(c) Describe an experiment to demonstrate the presence of bacteria under the finger nails.
« Previous
≡
Next »