Students’ Learning Outcomes
· Describe the disadvantages of microorganisms in daily life.
· Define infection.
· Identify ways by which microorganisms can enter the human body.
· Suggest ways to avoid infections.
Information for Teachers
· Microorganisms have many harmful effects.
· Many bacteria and fungi but all viruses can cause diseases in man, animals and plants.
· Many bacteria and fungi are responsible for the spoilage of feed.
· Typhoid, pneumonia, sore throat are examples of the diseases caused by bacteria.
· Flu, chicken pox, hepatitis and AIDS are caused by viruses.
· Fungi are responsible for many diseases like ringworm and athletes foot.
· The disease causing microorganisms are called germs.
· Germs can enter our bodies through mouth, nose and wounded skin.
· Infection is defined as the process by which a germ enters the body, divides to increase its number and in result causes diseases.
· Washing hands regularly keeping clean using boiled water and eating full cooked and safe food can prevent us from germs.
· Other germs which usually stay in certain parts of the body where they do not cause disease, will make a person sick if they find their way to another part of the body. For example, Escherichia coli (which is also sometimes known as E. coli) lives in the gut and helps digest food. However, if it gets outside the gut, E. coli can cause sickness such as bladder infection.
·
·
Food, water or air can be made dangerous to humans and other animals by things which are living in it or mixed into it. When this happens, it is said to be contaminated or polluted. Food and water can be contaminated by disease-causing germs.
· Germs can get into the body through the mouth, nose, breaks in the skin, eyes and genitals (privates). Once disease-causing germs are inside the body they can stop it from working properly. They may breed very quickly and in a very short time a small number of germs can become millions.
· Germs can cause disease by upsetting the way the body works. They do this when they produce toxins (poisons)
· Increase their number greatly by breeding and they can stop parts of the body from working properly, or attack and damage a particular part of the body
Material / Resources
Pictures / charts of diseases caused by microorganisms, pictures of bacteria, viruses and fungi, textbook.
Worm up Activity
· Divide the class into groups and ask them to discuss the following questions with each other.
—-What will happen, if we place a piece of bread / orange in open air for a few days?
—-Why do foods like oranges and bread go moldy?
—-How do we get flu?
—–Why should you cover your mouth while coughing?
—–How many of you wash your hands before eating? (Appreciate who raise their hands).
——-Why is it necessary to wash hands?
—–What are germs?
——-Can you see germs on your hands? (Expected response: Yes/ No)
——-Why can’t you see germs? (Expected response: Yes/ No.
—— Why can’t you see germs? 9Expected response: They are very tiny)
——Do you agree that there are living things that can’t be seen with naked eye?
(Expected response: yes/no)
· Now introduce the topic by using the previous knowledge. Inform them that besides beneficial effects of microorganisms. They have also harmful effects and sometimes cause infection.
Development
Activity 1
- To perform this activity. Do your preparations a few days before.
- Place a wet piece of bead in a plastic bag for some days.
- Show this piece of moldy bead to students and tell that fungi have grown on bread and it has turned poisonous.
- Conduct questioning answering session to explain that bacteria also spoil our food items.
- Share with the students that when milk-man brings milk to your home, your mother at once puts it on stove for boiling. What will happen if you keep this milk in kitchen and don’t boil it? (Expected response: “Its gets sour and we can’t drink it”)
- Explain that bacteria are always present in milk, which are killed after boiling the milk. When milk is not boiled, the bacteria grow in number and produce harmful chemicals in milk.
Activity 2
- Explain how an infection develops and results in disease.
- Make a flow chart / concept map to introduce the stages of occurrence of disease.
- Introduce common bacterial, viral and fungal disease by mentioning their causative germs, major symptoms and modes of transmission.
- There are, however, some germs which can make people sick if they enter their bodies, for example, hepatitis A and Salmonella germs.
Activity 2
- Ask them to make a list of the habits and ways which are helpful to avoid infections. (if possible show them pictures as given and write down their expected responses on board)
—–We should wash our hands especially before eating anything and after using toilet.
——We should immediately cleans the cuts and wounds and cover them with clean dressing.
——We should always cover our mouth with a handkerchief while coughing or sneezing.
——Germs in the water can be killed by boiling it.
—–Food always should be covered.
—–We should not eat foods sold by hawkers.
—–We should always keep our home, surroundings and ourselves clean.
Sum up / Conclusion
- Microorganisms are harmful for us in many ways.
- Many bacteria and fungi spoil our foods items.
- Bacteria cause many diseases in us like typhoid, pneumonia, sour throat, etc.
- Viruses cause flu, chicken pox, hepatitis and AIDS.
- Fungi are responsible for ringworm and athletes foot.
- Germs can get into the body through the mouth, nose, breaks in the skin, eyes and genitals
(privates).
- Infection is defined as the process by which germs enters the body, divides to increase its number and causes diseases.
Assessment
Ask the following questions to students:
-
- What are the germs and what is meant by term “infection”?
- What are the ways, germs can enter our bodies?
- Why some people prefer to use tetra pack milk?
- Will life be better with bacteria or without bacteria?
Activity 1
Ask students to complete the following worksheet.
-
- Which of these complaints, put a microorganisms? put a tick if it is caused by microorganisms and put a cross if it is not caused by microorganisms:
|
Name of Disease
|
Caused by
|
|
Flu
|
|
|
Bleeding in gums
|
|
|
Cut/burn on skin
|
|
|
Bone fracture
|
|
|
Chicken pox
|
|
|
Toothache
|
|
|
Nose bleeding
|
|
|
Headache
|
Activty 2
Write following diseases on board and ask students to write them in concerned column
1. Ringworm 2. Chicken pox 3. Flu
4. Influenza 5. Strep throat 6. Food poisoning
|
Bacterial diseases
|
Viral diseases
|
Fungal diseases
|
Follow up
Ask students to write a paragraph on their observations / reading about a housefly. The assignment paragraph should include these information: Where the housefly likes to sit? which disease it can spread? What should be the methods to get rid of houseflies?
