JAC Board Class 9th Science Important Questions Chapter 13 Why Do We Fall Ill
Multiple Choice Questions
Question 1.
The disease that affects our lungs is
(a) jaundice
(b) tuberculosis
(c) scabies
(d) herpes
Answer:
(b) tuberculosis
Question 2.
The BCG vaccine provides immunity against
(a) dengue
(b) influenza
(c) ebola
(d) tuberculosis
Answer:
(d) tuberculosis
Question 3.
Malaria is caused by
(a) Anopheles mosquito
(b) Bacteria
(c) Protozoa
(d) Virus
Answer:
(a) Anopheles mosquito
Question 4.
Trypanosoma, Leishmania and Plasmodium are the examples of
(a) protozoa
(b) worms
(c) fleas
(d) viruses
Answer:
(a) protozoa
Question 5.
Diarrhoea, cholera, typhoid are the diseases that have one thing in common, which is
(a) all of them are air-borne
(b) all of them are caused by a virus
(c) all of them are caused by contaminated food and water
(d) all of them cause headache
Answer:
(c) all of them are caused by contaminated food and water
Question 6.
HIV virus attacks which one of the following cells in our body?
(a) Liver cells
(b) Neurons
(c) Nephrons
(d) White blood cells
Answer:
(d) White blood cells
Question 7.
Pathogens of disease are
(a) viruses
(b) bacteria
(c) protozoa
(d) all of the above
Answer:
(d) all of the above
Question 8.
Which of the following is a worm – caused disease?
(a) Herpes
(b) Filariasis
(c) Rabies
(d) Conjunctivitis
Answer:
(b) Filariasis
Question 9.
Which of the following is not a viral disease?
(a) AIDS
(b) Rabies
(c) Polio
(d) Tuberculosis
Answer:
(b) Rabies
(d) Tuberculosis
Question 10.
Which of the following is caused by Plasmodium parasite?
(a) Hepatitis
(b) Jaundice
(c) Tuberculosis
(d) Malaria
Answer:
(d) Malaria
Analysing & Evaluating Questions
Question 11.
If you live in an overcrowded and poorly ventilated house, you may probably suffer from which of the following diseases?
(a) Cancer
(b) AIDS
(c) Air-borne diseases
(d) Cholera
Answer:
(c) Air – borne diseases
Question 12.
During infection or injuries, inflammation of body organs occurs due to the activation of
(a) nerves
(b) muscles
(c) immune system
(d) breathing
Answer:
(c) immune system
Question 13.
Suppose you are experiencing the symptoms of cough and breathlessness. Which organ of your body do you think might be affected?
(a) Kidney
(b) Lung
(c) Heart
(d) Stomach
Answer:
(b) Lung
Assertion-Reason Questions
Directions. In the following questions, the Assertions and the Reasons have been put forward. Read the statements carefully and choose the correct alternative from the following.
(A) Both the assertion and the reason are correct and the reason is the correct explanation of the assertion.
(B) The assertion and the reason are correct but the reason is not the correct explanation of the assertion.
(C) The assertion is true but the reason is false.
(A) Both the assertion and the reason are correct and the reason is the correct explanation of the assertion.
1. Assertion: DPT is a triple antigen.
Reason: DPT is administered against three diseases namely diphtheria, pertussis and tetanus.
Answer:
(A) Both the assertion and the reason are correct and the reason is the correct explanation of the assertion.
2. Assertion: Antibiotics are effective against both the bacteria and the viruses.
Reason: Viruses have many biochemical mechanisms of their own.
Answer:
(A) Both the assertion and the reason are correct and the reason is the correct explanation of the assertion.
3. Assertion: Male Anopheles mosquitoes do not spread malaria.
Reason: Male Anopheles mosquitoes do not feed on human blood.
Answer:
(A) Both the assertion and the reason are correct and the reason is the correct explanation of the assertion.
4. Assertion: Typhoid spreads through contaminated food and water.
Reason: Typhoid can never become an epidemic in a locality.
Answer:
(C) The assertion is true but the reason is false.
5. Assertion: HIV attacks the immune system of a person.
Reason: HIV is responsible for AIDS in people infected with it.
Answer:
(B) The assertion and the reason are correct but the reason is not the correct explanation of the assertion.
Very Short Answer Type Questions
Question 1.
What do you understand by symptoms of a disease?
Answer:
Symptoms are the signs of a disease which indicate the presence of that particular disease.
Question 2.
What are acute diseases?
Answer:
Acute diseases are diseases that last for a very short period of time.
Question 3.
What are chronic diseases?
Answer:
Chronic diseases are diseases that last for a very long period of time.
Question 4.
What are infectious diseases?
Answer:
Infectious diseases are diseases that can spread from an infected person to another healthy person, e. g., ebola.
Question 5.
Name any one disease caused due to genetic abnormality.
Answer:
Sickle-cell anaemia.
Question 6.
Name two diseases caused by protozoa.
Answer:
Trichomoniasis and malaria.
Question 7.
Name two diseases each caused by bacteria, viruses and fungi.
Answer:
Bacteria – typhoid, cholera; Viruses – ebola, mumps; Fungi – Jock-itch, ringworm.
Question 8.
Write the full form of AIDS.
Answer:
Acquired Immunodeficiency Syndrome.
Question 9.
Which organism causes sleeping sickness?
Answer:
A protozoan called Trypanosoma causes sleeping sickness.
Question 10.
Name the causative agent of kala – azar?
Answer:
Leishmania.
Question 11.
Name two air-borne diseases.
Answer:
Anthrax and smallpox.
Question 12.
Name two organ specific diseases.
Answer:
Autoimmune hepatitis which affects the liver and Grave’s disease which affects the thyroid.
Question 13.
Which virus is responsible for AIDS?
Answer:
HIV virus is responsible for AIDS.
Question 14.
State the organs affected by the following diseases. jaundice, malaria, typhoid.
Answer:
Jaundice: liver; malaria – liver and RBCs; typhoid – infects the blood.
Question 15.
How do we kill microbes that enter our bodies?
Answer:
We kill disease: causing microbes with the help of medicines that block the synthesis pathways of microbes.
Question 16.
What are disease specific means of prevention?
Answer:
Disease specific means of prevention is the use of vaccine which prevents specific diseases from affecting us, e.g., tetanus vaccine, rabies vaccine, etc.
Question 17.
Why is the creation of antiviral drugs hard?
Answer:
Viruses grow inside the host and use the host cell machinery and pathways for all its biological processes. Hence, antibiotics are not able to target the virus-specific pathways. Moreover, viruses can alter their mechanisms at a very high rate, so it becomes difficult to target a specific mechanism.
Analysing & Evaluating Questions
Question 18.
Suppose your friend is suffering from severe cold and it makes him sneeze frequently heavily. What would you suggest him as a precautionary measure so that you do not become infected with the disease?
Answer:
Severe cold or cough are airborne diseases which spread through inhalation of respiratory droplets that are released by sneezing and coughing by an infected individual. Therefore, I would suggest my friend to cover his mouth while sneezing or coughing so that virus responsible for causing this disease does not infect others.
Question 19.
A person is suffering from fever and headache from quite a period of time. He is suspecting that it may be typhoid. What should he do to confirm whether it is the same disease?
Answer:
Confirmation of a particular disease can be done by undergoing proper medical check up and laboratory tests under the supervision of a doctor.
Question 20.
Suppose a person is suffering from jaundice. Whether prescribing him penicillin will be useful or not? Name the target organ for jaundice.
Answer:
No, penicillin would not be useful in the treatment of jaundice because it is a viral diseases. Target organ for jaundice is liver.
Short Answer Type Questions
Question 1.
Define health, disease, pathogens and antibiotics.
Answer:
Health. It is a state of mental, physical and social well-being.
Disease. It is the deviation from the normal healthy well-being of an individual.
Pathogens. They are disease-causing microbes, e.g., bacteria, worms, fungi, etc.
Antibiotics. These are drugs that block the biochemical pathways important to bacteria, thereby killing them.
Question 2.
What are the two main causes of a disease?
Answer:
The two main causes are immediate and contributory causes. Immediate cause-this is due to pathogens entering our bodies. Contributory cause-these are the secondary factors which allow these pathogens to enter our bodies through dirty water, contaminated food, infected surroundings, etc.
Question 3.
Define and give examples of vaccines.
Answer:
Vaccine is an antigenic substance prepared from the agent causing the disease, which is given in advance to a body to provide immunity against that specific disease, e.g., chickenpox vaccine, hepatitis vaccine, polio vaccine.
Question 4.
What is antibiotic penicillin? Give its function.
Answer:
Penicillin is a drug prepared from the fungus Penicillium, which does not allow bacteria to build its protective cell wall, thus it dies off easily. It is used to cure diseases and infections caused by bacteria.
Question 5.
A bacterium is a cell which is destroyed by an antibiotic. Our body is also made up of cells. How come antibiotics do not affect our bodies as well?
Answer:
An antibiotic blocks the biochemical pathway through which bacteria build a protective cell wall. Human body cells do not have this cell wall, so antibiotics cannot have any such effect on our body.
Question 6.
How can cholera become an epidemic in a locality?
Answer:
Cholera is a communicable disease that spreads through contaminated water and food. Let’s say, a person living in a locality contaminates the local water supply with cholera through his excreta. Now, all the people of that locality who drink that water will get infected with cholera.
Question 7.
Why are sick patients asked to take bed rest?
Answer:
Sick patients are asked to take bed rest so that they can conserve their energy which can be used to heal their recovering organs. Moreover, if they move around, there are higher chances of them getting infected with other diseases as their immune system is already weak.
Question 8.
Write a short note on malaria, its symptoms and control.
Answer:
Malaria is caused by a protozoan that lives in blood. The parasite enters our bodies when a female Anopheles mosquito, having the protozoa named Plasmodium, sucks our blood. This protozoan affects our liver and blood cells.
- Symptoms: muscular pain, headache and very high fever.
- Control: keeping the surroundings clean with no stagnant water, using mosquito repellents, use of quinine drug.
Question 9.
What is AIDS? How does a person contract AIDS?
Answer:
AIDS or Acquired Immunodeficiency Syndrome is a disease caused by the Human immuno deficiency virus. A person with AIDS has severely affected immune system. Hence, he or she dies from other diseases that thrive from the lack of Acquired WBCs in the HIV infected body.
A person contracts AIDS in the following ways:
- Blood transfusion
- Sexual intercourse
- From infected mother to a baby (in the womb)
- Sharing of needles with infected people
- Breast feeding (if the feeder is infected).
Question 10.
Becoming infected by an infectious microbe does not always develop into a disease. Why?
Answer:
This is because our immune system is always active and when foreign particles (microbes) enter our body, the immune system instantly attacks it, trying to kill it. So, in cases where our immune system is successful in killing the infectious microbe, we don’t develop the disease it was supposed to cause.
Question 11.
(a) Why is a balanced diet necessary for maintaining a healthy body?
(b) Name two diseases caused by junk food.
Answer:
(a) A balanced diet provides all the nutrients required by our body in the correct amount. It helps to keep our immune system healthy,
(b) Two diseases caused by junk food are obesity and high blood pressure.
Analysing & Evaluating Questions
Question 12.
No polio cases have been reported from India since the last three years. On that basis, WHO has presented certification of poliofree status to India.
1. Which pathogen is responsible for causing polio in children?
2. How the principle of immunisation is implemented for eliminating polio?
3. What is OPV?
Answer:
- Poliomyelitis virus.
- Oral vaccines for polio are given periodically to children under five years to age to eliminate the occurrence of the disease. These vaccines are the preparations of weak forms of polio virus strains. These preparations stimulate the body to produce antibodies in response to the exposure to polio viruses. Thus, body becomes immune to the polio disease.
- Oral Polio Vaccine.
Question 13.
Sachin’s younger brother was suffering from diarrhoea and vomiting. So he made Oral Rehydration Solution (ORS) and gave it to his brother to drink frequently. Then he thought to take him to the doctor for medical checkup.
1. What may be the cause of diarrhoea and vomiting?
2. Name the causative agents for these diseases?
3. Why Sachin gave ORS to his brother?
Answer:
- Diarrhoea and vomiting may occur due to the consumption of contaminated food and water.
- The causative agents for these are mainly bacteria, but some protozoa and viruses can also cause diarrhoea and vomiting.
- Due to diarrhoea and vomiting, the body loses excess of water and other salts leading to dehydration of the body. Therefore, Sachin used his knowledge to save his brother from the discomfort of dehydration by giving him ORS.
Long Answer Type Questions
Question 1.
If someone in the family gets an infectious disease, what precautionary steps will you take to help that person recover fast and prevent other family members from getting infected?
Answer:
(a) The infected person should be kept isolated in a separate room.
(b) The surroundings and the house need to be kept clean.
(c) His (the patient) clothes and utensils should be sanitised regularly.
(d) Separate towels, sheets and blankets should be used by the patient.
(e) Clean and boiled drinking water should be given to the patient.
(f) A balanced and nutritious meal should be provided to the patient.
(g) The patient should be allowed enough rest to recover fully.
Question 2.
What are the different methods used for the treatment and prevention of diseases?
Answer:
Principles of treatment for diseases are:
(a) To reduce the symptoms of the disease.
(b) To kill the cause of the disease, i.e., to kill the disease-causing microbes like bacteria, fungi, protozoa.
Principles of prevention are:
(a) General ways: It relates to preventing exposure to the microbes, which can be done in the following ways.
- For air – borne infections. Avoid public spaces, cover your nose while coughing and sneezing.
- For water – borne infections. Drink safe and filtered water.
- For vector – borne diseases. Keep the surroundings clean, cover your food and water, do not allow stagnant water to collect.
- Self – immunity. Exercise regularly to keep your immune system strong.
(b) Specific ways: By getting vaccination, regular checkups and medications.
Question 3.
State the mode of transmission for the following diseases. malaria, AIDS, jaundice, typhoid, cholera, rabies, tuberculosis, diarrhoea, hepatitis, influenza.
Answer:
| Disease | Mode of transmission |
| 1. Malaria | Mosquito bite (female Anopheles mosquito) |
| 2. AIDS | Infected blood, semen, mother’s milk, sharing needle of an infected person |
| 3. Jaundice | Contaminated water |
| 4. Typhoid | Contaminated food and water |
| 5. Cholera | Contaminated food and water |
| 6. Rabies | Bite of a rabid animal |
| 7. Tuberculosis | Cough and sneeze droplets |
| 8. Diarrhoea | Contaminated food and water |
| 9. Hepatitis | Contaminated food and water |
| 10. Influenza | Cough and sneeze droplets |
Question 4.
(a) What causes chickenpox?
(b) State a few precautionary measures for it.
Answer:
(a) Chickenpox is caused by a virus called varicella-zoster virus,
(b) Some precautionary steps for chicken pox are.
- The infected person should avoid direct contact with people.
- His clothes should be soaked in boiling water before washing so as to kill the virus.
- Vaccination should be taken in advance to prevent the disease.
Analysing & Evaluating Questions
Question 5.
Children living in slum areas frequently suffer from symptoms such as abdominal pain, diarrhoea, loose motions, vomiting and loss of appetite.
(a) Name the target organ or organ system for the occurrence of these symptoms.
(b) Why children are frequently suffering from these symptoms?
(c) What should be done to improve the health status of these children?
Answer:
(a) The target organ or organ system for the occurrence of these symptoms is alimentary canal.
(b) These symptoms appear frequently in the children because they live in unhygienic environment where there is non availability of clean drinking water. Hence, making them prone to infections of alimentary canal.
(c) The local authorities responsible for providing public health services should be informed regarding these health problems in the children. There should be provision of clean drinking water supply and proper sanitation in the area, so that the spread of water-borne infections can be prevented.
Activity 1
- Find out what provisions are made by your local authority (Panchayat/ Municipal Corporation) for the supply of clean drinking water.
- Find out if all the people in your locality are able to access this.
Observations:
- Local authority, i.e., Municipal Corporation of our area recycles the water. Used water is treated in water treatment plants, chlorinated and supplied through pipes to people. Water taken from river is also cleaned and made potable.
- People, who live outside municipal limits use underground water, which is supposed to be safe, by drawing water through handpumps, wells and tube-wells.
Activity 2
- Rabies virus is spread by the bite of infected dogs and other animals. There are anti-rabies vaccines for both humans and animals.
- Find out the plan of your local authority for the control of rabies in your neighbourhood. Also find if these measures are adequate or not. Suggest some improvements.
Observations:
- Local authorities have plan to provide free anti-rabies vaccination at health centres, dispensaries, etc., and also catch the stray dogs. But animal loving organisations force to let them free. Pet owners are required to get anti-rabies vaccination to their dogs/ cats. But this rule is not strictly followed.
- Suggestions.
- People should be educated through campaigns about anti-rabies vaccination for both humans and animals.
- Stray dogs/cats/other animals should be provided with anti-rabies vaccination.
- Pet owners should be strictly instructed to get themselves and their pets vaccinated against rabies.
Value Based Questions
Question 1.
Radha’s brother, who is 5 years old, had high fever for two days. Doctor prescribes him antibiotics. Radha hesitantly asks for the name of the disease his brother had and why he was advised to take antibiotics without any diagnosis.
1. Is fever a disease?
2. What is the role of antibiotics?
3. What values of Radha are reflected in the above act?
Answer:
- Fever is not a disease; it is a symptom.
- Antibiotics are medicines advised to be taken only when the immune system of a patient is unable to fight against the microbes.
- Radha showed moral responsibility and general awareness.
Question 2.
Jyoti was suffering from chickenpox and was advised to stay at home by her doctor. Jyoti’s friend persuades her to go for class picnic along with her and have fun. But Jyoti refuses and stays at home.
1. What is the cause of chickenpox?
2. Give one precaution for it.
3. What value of Jyoti is reflected in not going for picnic?
Answer:
- Virus causes chickenpox.
- One precaution for avoiding spread of chickenpox is to stay away from public places when one is suffering from it and take vaccination.
- Jyoti showed moral responsibility and self-awareness.