1. Which one of the following is not a viral disease?
(a) Dengue (b) AIDS (c) Typhoid (d) Influenza
Answer: (c) Typhoid
[ Typhoid is not a viral disease. It is caused by bacteria (Salmonella typhi).]
2. Which one of the following is not a bacterial disease?
(a) Cholera (b) Tuberculosis (c) Anthrax (d) Influenza
Answer: (d) Influenza
[ Influenza is caused by a virus, while Cholera, Tuberculosis and Anthrax are caused by bacteria.]
3. Which one of the following disease is not transmitted by mosquito?
(a) Brain fever (b) Malaria (c) Typhoid (d) Dengue
Answer: (c) Typhoid
[ Typhoid spreads through contaminated food and water, not by mosquitoes. Brain fever, Malaria, and Dengue are mosquito-borne diseases. ]
4. Which one of the following disease is caused by bacteria?
(a) Typhoid (b) Anthrax (c) Tuberculosis (d) Malaria
Answer: (a), (b), (c)
[ Typhoid, anthrax, and tuberculosis are caused by bacteria. Malaria is caused by Plasmodium parasite (not bacteria).]
5. Which one of the following diseases is caused by protozoans?
(a) Malaria (b) Influenza (c) AIDS (d) Cholera
Answer: (a) Malaria
[ Malaria is caused by protozoans (Plasmodium parasite). Influenza is viral, AIDS is viral (HIV), Cholera is bacterial.]
6. Which one of the following has a long term effect on the health of an individual?
(a) Common cold (b) Chicken pox (c) Chewing tobacco (d) Stress
Answer: (c) Chewing tobacco
[Chewing tobacco causes long-term effects like oral cancer, gum disease and tooth loss. Common cold and chicken pox are acute (short-term) illnesses. Stress can be chronic but is manageable without permanent damage like tobacco's effects.]
7. Which of the following can make you ill if you come in contact with an infected person?
(a) High blood pressure (b) Genetic abnormalities (c) Sneezing (d) Blood cancer
Answer: (c) Sneezing
[ Sneezing from an infected person spreads germs (like viruses/bacteria) through droplets, causing illness in others. ]
8. AIDS cannot be transmitted by
(a) sexual contact (b) hugs (c) breast feeding (d) blood transfusion
Answer: (b) hugs
[ AIDS (HIV) spreads through sexual contact, breast feeding and blood transfusion. It is not transmitted by casual hugs, touching, or sharing food.]
9. Making anti-viral drugs is more difficult than making anti-bacterial medicines because
(a) viruses make use of host machinery
(b) viruses are on the border line of living and non-living
(c) viruses have very few biochemical mechanisms of their own
(d) viruses have a protein coat
Answer: (c) viruses have very few biochemical mechanisms of their own
[ Anti-bacterial drugs target bacteria's own biochemical pathways. Viruses lack independent mechanisms and rely on host cell machinery, offering few virus-specific targets for drugs without harming host cells.]
10. Which one of the following causes kala-azar?
(a) Ascaris (b) Trypanosoma (c) Leishmania (d) Bacteria
Answer: (c) Leishmania
[ Kala-azar (also called visceral leishmaniasis) is caused by the protozoan parasite Leishmania. It spreads through the bite of an infected sandfly. ]
11. If you live in a overcrowded and poorly ventilated house, it is possible that you may suffer from which of the following diseases
(a) Cancer (b) AIDS (c) Air borne diseases (d) Cholera
Answer: (c) Air borne diseases
[ Overcrowded and poorly ventilated places help germs spread easily through air, causing diseases like tuberculosis, cold and flu.]
12. Which disease is not transmitted by mosquitoes?
(a) Dengue (b) Malaria (c) Brain fever or encephalitis (d) Pneumonia
Answer: (d) Pneumonia
[ Dengue, malaria and brain fever (Japanese encephalitis) are transmitted by mosquitoes. Pneumonia is mainly caused by bacteria/viruses and spreads through respiratory droplets, not mosquitoes.]
13. Which one of the following is not important for individual health?
(a) Living in clean space (b) Good economic condition
(c) Social equality and harmony (d) Living in a large and well furnished house
Answer: (d) Living in a large and well furnished house
[ Individual health depends on clean living space, good economic condition and social equality, but a large or well-furnished house is not essential for good health.]
14. Choose the wrong statement
(a) High blood pressure is caused by excessive weight and lack of exercise.
(b) Cancers can be caused by genetic abnormalities
(c) Peptic ulcers are caused by eating acidic food
(d) Acne in not caused by staphylococci
Answer: (c) Peptic ulcers are caused by eating acidic food
[ Peptic ulcers are mainly caused by Helicobacter pylori bacteria (or certain drugs), not by eating acidic food.]
15. We should not allow mosquitoes to breed in our surroundings because they
(a) multiply very fast and cause pollution (b) are vectors for many diseases
(c) bite and cause skin diseases (d) are not important insects
Answer: (b) are vectors for many diseases
[ Mosquitoes act as vectors (carriers) and transmit serious diseases like malaria, dengue, chikungunya, Zika and filariasis. Preventing their breeding reduces these disease risks.]
16. You are aware of Polio Eradication Programme in your city. Children are vaccinated because
(a) vaccination kills the polio causing microorganisms (b) prevents the entry of polio causing organism
(c) it creates immunity in the body (d) all the above
Answer: (c) it creates immunity in the body.
[ Vaccination introduces a weakened or inactive form of the pathogen into the body. This helps the immune system produce antibodies and memory cells, so the body can fight the disease quickly in the future.]
17. Viruses, which cause hepatitis, are transmitted through
(a) air (b) water (c) food (d) personal contact
Answer: (b) water
[ Hepatitis viruses are mainly transmitted through contaminated water.]
18. Vectors can be defined as
(a) animals carry the infecting agents from sick person to another healthy person
(b) microorganisms which cause many diseases
(c) infected person
(d) diseased plants
Answer: (a) animals carry the infecting agents from sick person to another healthy person .
[ Vectors are living organisms like mosquitoes and flies that transmit disease causing agents from an infected host to a healthy individual.]
19. Give two examples for each of the following
(a) Acute diseases (b) Chronic diseases (c) Infectious diseases (d) Non-infectious diseases
Answer: (a) Two examples of acute diseases are common cold and malaria.
(b) Two examples of chronic diseases are diabetes and tuberculosis.
(c) Two examples of infectious diseases are COVID-19 and chickenpox.
(d) Two examples of non infectious diseases are cancer and hypertension (high blood pressure).
20. Name two diseases caused by Protozoans.What are their causal organisms?
Answer: Two diseases caused by protozoans are Kala-azar and Sleeping sickness.
Two diseases caused by protozoans are:
(i) Kala-azar is caused by Leishmania, a protozoan parasite.
(ii) Sleeping sickness is caused by Trypanosoma, a protozoan parasite.
21. Which bacterium causes peptic ulcers? Who discovered the above pathogen for the first time?
Answer: The bacterium that causes peptic ulcers is Helicobacter pylori.
The pathogen Helicobacter pylori was discovered for the first time by Barry Marshall and Robin Warren.
22. What is an antibiotic? Give two examples
Answer: An antibiotic is a type of medicine which is used to kill or stop the growth of harmful bacteria in our body . Two examples of antibiotics are Penicillin and Streptomycin .
23. Fill in the blanks
(a) Pneumonia is an example of ——— disease.
(b) Many skin diseases are caused by———.
(c) Antibiotics commonly block biochemical pathways important for the growth of ———.
(d) Living organisms carrying the infecting agents from one person to another are called ———.
Answer: (a) Pneumonia is an example of infectious disease.
(b) Many skin diseases are caused by fungi.
(c) Antibiotics commonly block biochemical pathways important for the growth of bacteria.
(d) Living organisms carrying the infecting agents from one person to another are called vectors.
24. Name the target organs for the following diseases
(a) Hepatitis targets———.
(b) Fits or unconsciousness targets ———.
(c) Pneumonia targets ———.
(d) Fungal disease targets ———.
Answer: (a) Hepatitis targets the liver.
(b) Fits or unconsciousness targets the brain.
(c) Pneumonia targets the lungs.
(d) Fungal disease targets the skin.
25. Who discovered ‘vaccine’ for the first time? Name two diseases which can be prevented by using vaccines.
Answer: Edward Jenner discovered the vaccine for the first time. He developed the vaccine for smallpox.
Two diseases that can be prevented by vaccines are polio and measles .
26. Fill in the blanks
(a) ——— disease continues for many days and causes——— on body.
(b) ———disease continues for a few days and causes no longer term effect on body.
(c) ——— is defined as physical, mental and social well-being and comfort.
(d) Common cold is——— disease.
(e) Many skin diseases are caused by———.
Answer: (a) Chronic disease continues for many days and causes long-term effects on body.
(b) Acute disease continues for a few days and causes no long-term effect on body.
(c) Health is defined as physical, mental and social well-being and comfort.
(d) Common cold is an infectious disease.
(e) Many skin diseases are caused by fungi.
27. Classify the following diseases as infectious or non-infectious.
(a) AIDS (b) Tuberculosis (c) Cholera (d) High blood pressure (e) Heart disease (f) Pneumonia (g) Cancer
Answer: The classification are :
|
Infectious diseases |
Non-infectious diseases |
|
(a) AIDS (b) Tuberculosis (c) Cholera (f) Pneumonia |
(d) High blood pressure (e) Heart disease (g) Cancer
|
28. Name any two groups of micro-organisms from which antibiotics could be extracted.
Answer: The two groups of micro organisms from which antibiotics can be extracted are:
(i) Fungi such as penicillium from which penicillin is extracted.
(ii) Bacteria such as streptomyces from which streptomycin is extracted.
29. Name any three diseases transmitted through vectors.
Answer: Three diseases transmitted through vectors are:
(i) Malaria is transmitted by the female Anopheles mosquito.
(ii) Dengue is transmitted by the Aedes mosquito.
(iii) Chikungunya is transmitted by the Aedes mosquito.
30. Explain giving reasons
(a) Balanced diet is necessary for maintaining healthy body.
(b) Health of an organism depends upon the surrounding environmental conditions.
(c) Our surrounding area should be free of stagnant water.
(d) Social harmony and good economic conditions are necessary for good health.
Answer: (a) A balanced diet is necessary for maintaining a healthy body because it provides all essential nutrients needed for growth energy and proper functioning of the body.
(b) Health of an organism depends upon the surrounding environmental conditions because clean air water and surroundings help prevent diseases and keep the body healthy.
(c) Our surrounding area should be free of stagnant water because stagnant water becomes a breeding place for mosquitoes that spread diseases like malaria and dengue.
(d) Social harmony and good economic conditions are necessary for good health because they provide proper living conditions nutritious food education and healthcare facilities.
31. What is a disease? How many types of diseases have you studied? Give examples.
Answer: A disease is a condition in which the normal functioning of the body or any part of it is disturbed. A person suffering from disease may feel pain, weakness, discomfort or show abnormal symptoms.
There are mainly two types of diseases studied : :
(i) Acute diseases : These last for a short period of time. Examples: Cold, fever and cholera.
(ii) Chronic diseases : These last for a long time and may have long-term effects on the body. Examples: Tuberculosis, diabetes and asthma.
32. What do you mean by disease symptoms ? Explain giving two examples?
Answer: Disease symptoms are the signs or changes in the body that indicate the presence of a disease. They help in identifying that something is wrong in the body.
Examples: (i) Cough and sneezing are seen in common cold. (ii) Fever and chills are seen in malaria.
33. Why is immune system essential for our health?
Answer: The immune system protects the body from disease causing microorganisms called pathogens. It identifies and destroys germs before they can cause harm. Without a strong immune system even minor infections can become serious. Vaccines also help by strengthening the memory of the immune system against specific diseases.
34. What precautions will you take to justify “prevention is better than cure”.
Answer: We should take the following precautions:
(i) Eat a balanced diet and drink clean water to keep the body strong.
(ii) Maintain personal hygiene like washing hands before eating and after using the toilet.
(iii) Keep our surroundings clean and avoid stagnant water to prevent mosquito breeding.
(iv) Take vaccinations on time to protect against diseases.
(v) Do regular exercise and get proper rest.
35. Why do some children fall ill more frequently than others living in the same locality?
Answer: Some children fall ill more frequently than others in the same locality due to:
(i) Poor immune system due to malnutrition or lack of proper diet.
(ii) Lack of vaccination because they are not immunized against common infectious diseases.
(iii) Unclean habits such as not washing hands and drinking unsafe water.
(iv) Poor economic condition due to inability to afford proper food clothing or healthcare.
36. Why are antibiotics not effective for viral disease?
Answer: Antibiotics are not effective against viral diseases because viruses have a different structure and mode of living. Antibiotics act on bacterial cell walls or metabolic activities but viruses do not have cell walls and live inside host cells. Therefore antibiotics cannot destroy viruses without affecting the host cells.
37. Becoming exposed to or infected with an infectious microbe does not necessarily mean developing noticeable disease. Explain.
Answer: Just because a person is exposed to or infected by a disease causing microbe does not mean that the person will definitely become sick. This happens because our body has a defence system called the immune system. If the immune system is strong it can fight the germs before they multiply enough to cause symptoms. Sometimes the number of germs entering the body is very small so the body destroys them easily. Also some people may carry the microbes without showing any symptoms. Such people are called carriers. For example the bacteria that cause typhoid may live in a person’s body without making the person ill but can still spread the disease to others. Therefore infection does not always lead to disease.
38. Give any four factors necessary for a healthy person.
Answer: For a person to remain healthy, the following four factors are necessary:
(i) Balanced Diet : A person should eat food that contains all the necessary nutrients like carbohydrates, proteins, fats, vitamins and minerals in the right amounts. This keeps the body strong and energetic.
(ii) Personal Hygiene : Regular habits like bathing, washing hands before eating, brushing teeth and keeping nails clean help prevent infections.
(iii) Clean Surroundings : Living in a clean environment with proper waste disposal, clean water and fresh air reduces the risk of catching diseases.
(iv) Regular Exercise and Rest : Physical activities like playing, running or yoga keep the body fit, while proper sleep and rest help the body recover and stay fresh.
39. Why is AIDS considered to be a ‘Syndrome’ and not a disease?
Answer: AIDS is considered a syndrome and not just a single disease because it is a collection of many different signs symptoms and infections occurring together. The full form of AIDS is Acquired Immunodeficiency Syndrome. In this condition the HIV virus weakens the immune system so badly that the body becomes unable to fight even minor infections. As a result the person suffers from multiple diseases like pneumonia tuberculosis skin infections and diarrhea at the same time. Since it includes a group of diseases rather than one specific illness it is called a syndrome. In simple words AIDS is not just one disease; it is a bundle of many diseases caused by a weakened immune system.
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