UNIT NO.3
Immunity and Diseases
(Solved Exercise)
3.2 Give short answers.
1. Define the following:
(a) Pathogen
(b) Antigen
(c) Infection
(d) Phagocytosis
3.3 Answer the following questions
1. Describe the physical barriers against the pathogens in human body.
2. Explain the non-specific defence against pathogens in human body.
3. Give brief introduction of pathogens (virus, bacteria, fungi). Explain how can they
enter human body?
4. What are infectious diseases? Give examples.
5. Describe the parts of immune system.
6. How can we avoid infections?
3.4 Constructed Response Questions
1. What do you think are the modes of transmission of diseases?
Answer:
1. Touching: Germs can move from one person to another when they touch each other. This can happen when you shake hands, hug, or share things like toys or pencils.
2. Coughing and Sneezing: When someone coughs or sneezes, tiny droplets from their nose or mouth can carry germs through the air. If you breathe in these droplets, you might get sick.
3.Contaminated Objects: Germs can live on surfaces like doorknobs, tables, or toys. If you touch something that has germs on it and then touch your face, you could get sick.
4. Insects and Animals: Some diseases are spread by bugs like mosquitoes or ticks, or by animals like rats. These bugs or animals can carry germs and pass them on when they bite or touch people.
5. Dirty Water: If water is not clean, it can have germs in it. Drinking or swimming in dirty water can make you sick.
6. Food: Sometimes, germs can get into the food we eat. If food isn’t cooked or handled properly, it can make us sick when we eat it.
2. What do mean by personal hygiene? Describe some basic principles in this regard.
Answer:
1. Washing your hands with soap and water regularly is very important. Wash your hand before eat, after you see washroom/toilet, and whenever you touch something used by a sick person.
2. Take bath at least once a day.
3. Wash fruits and vegetables before eating.
4. Wearing clean clothes every day helps to keep you fresh and prevents the spread of germs. Change your underwear, socks, and other clothes daily.
3. Illustrate and give brief introduction of lymphoid organs.
Answer:
3.5 Investigate how can we strengthen our immune system?
Answer:
3.6 Make placards to create awareness against infectious diseases.
Answer: