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ScienceClass 9CBSE

Why is immune system essential for our health?

Soln: Immune system is the defense line of our body. Immune system comprise of different kind of cells that kills the infecting microorganism. When a pathogen enters our body our immune system send immune cells to fight and kill pathogens. If our immune system clear the disease causing pathogens we stay healthy. If our immune system fail to clear pathogen we encounter disease. In order to be healthy immune system is essential.

ScienceClass 9CBSE

What do you mean by disease symptoms? Explain giving two examples?

Soln: When we encounter with disease some or more parts of our body start behaving abnormal and give certain signs which are not normal. Such visible changes in our body are called as symptoms. Ex: When we get cold our body responds and we start coughing and sneezing and in some cases our body temperature increase these changes in our body are the symptoms of common cold. When we get Malaria our body temperature increases our body start shivering due to chills.

ScienceClass 9CBSE

What is a disease? How many types of diseases have you studied? Give examples.

Each organs of an organ system has specific functions to do. When this functioning change or disrupt it leads to a condition called disease. These changes results in some adverse effects on body’s normal functioning and the changes observed are called signs and symptoms of the disease. Types of Diseases Acute: Diseases that last for only very short periods of time, are called acute diseases. Ex: common cold Chronic: Diseases that last for a long time, even as much as a lifetime are called chronic diseases. Ex: elephantiasis. Infectious: Diseases which are caused by microorganisms are called infectious diseases. These disease can spread from one person to another by vectors or by other means such as air, food and water. Ex: Typhoid Non- Infectious Diseases that are not caused by infectious agents. Their causes vary, but they are not external causes like microbes that can spread in the community. Instead, these are mostly internal, non-infectious causes. Example: High blood pressure.

ScienceClass 9CBSE

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.

Soln: Food is essential for the growth and normal function of our body. Balanced diet is the one which consists of all the essential nutrients in an appropriate Balanced diet provided appropriate amount of biomolecules such as carbohydrates, lipids, proteins, vitamins and minerals which are very essential for our growth and body functioning. Imbalance in diet lead to many physical and physiological diseases. Health is defined as physical, mental and social well-being and Health is always dependent on our surroundings and if our environment is unhygienic we get disease. We get cold and cough in rainy and winter season. Our environment conditions are very important for being healthy. Stangnant water is the breeding environment for mosquitos. Mosquitos spread many diseases like Malaria, Dengue, Elephantisis, chickungunys In order to stop spread of these disease our surrounding should be free of stagnant water. Human beings are social We live in different localities and environments. In order to lead a healthy life we have to keep our environment clean. We need good hygienic food to lead healthy life which depends on our earnings. We often encounter diseases, in order to get treatment we need money and our economic status should be strong to afford the treatments.

ScienceClass 9CBSE

Name any three diseases transmitted through vectors.

Soln: Malaria transmitted by mosquitos Rabies transmitted by mad dogs Elephantisis is transmitted by mosquitos.

ScienceClass 9CBSE

Name any two groups of micro-organisms from which antibiotics could be extracted.

Bacteria and fungi

ScienceClass 9CBSE

Classify the following diseases as infectious or non-infectious. (a) AIDS (b) Tuberculosis (c) Cholera (d) High blood pressure (e) Heart disease (f) Pneumonia Cancer

Soln: AIDS – Infectious disease Tuberculosis - Infectious disease Cholera - Infectious disease High blood pressure- non- Infectious disease Heart disease non- Infectious disease Pneumonia-Infectious disease Cancer- non- Infectious disease

ScienceClass 9CBSE

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———.

Soln: Chronic disease continues for many days and causes long term effect on Acute disease continues for a few days and causes no longer term effect on Health is defined as physical, mental and social well-being and Common cold is viral Many skin diseases are caused by Fungi.

ScienceClass 9CBSE

Who discovered ‘vaccine’ for the first time? Name two diseases which can be prevented by using vaccines.

Soln: Edward Jenner discovered vaccine. Polio and tetanus are the disease which can be prevented by using vaccines.

ScienceClass 9CBSE

Name the target organs for the following diseases (a) Hepatitis targets———. (b) Fits or unconsciousness targets ———. (c) Pneumonia targets ———. (d) Fungal disease targets ———.

Soln: Hepatitis targets Liver. Fits or unconsciousness targets Brain. Pneumonia targets Fungal disease targets Skin.

ScienceClass 9CBSE

Which bacterium causes peptic ulcers? Who discovered the above pathogen for the first time?

Soln: Pneumonia is an example of Bacterial Many skin diseases are caused by Antibiotics commonly block biochemical pathways important for the growth of Bacteria. Living organisms carrying the infecting agents from one person to another are called Vectors.

ScienceClass 9CBSE

Name two diseases caused by Protozoans What are their causal organisms?

Malaria is caused by Plasmodium vivax Kala azar is caused by Leishmania

ScienceClass 9CBSE

Give two examples for each of the following (a) Acute diseases (b) Chronic diseases (c) Infectious diseases Non-infectious diseases

Soln: Acute diseases – Flu, Viral fever Chronic diseases – Tuberculosis, Elephantisis Infectious diseases –Small pox, chicken pox Non-infectious diseases- Diabetes, Cancer

ScienceClass 9CBSE

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 diseased plants

Soln: Answer is (a) animals carry the infecting agents from sick person to another healthy person.

ScienceClass 9CBSE

Viruses, which cause hepatitis, are transmitted through (a) air (b) water (c) food personal contact

Soln: Answer is (b) water

ScienceClass 9CBSE

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 all the above

Soln: Answer is (c) it creates immunity in the body Explanation: Vaccines create immunity against the pathogens against which it is designed.

ScienceClass 9CBSE

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 are not important insects

Soln: Answer is (b) are vectors for many diseases Explanation: Mosquitos are dangerous as they spread disease like Malaria, Dengue, Japanese encephalitis etc.

ScienceClass 9CBSE

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 Acne in not caused by staphylococci

Soln: Answer is (c) Peptic ulcers are caused by eating acidic food Explanation: Answer c is wrong because peptic ulcers are caused by a bacterium call as Helicobacter pylori

ScienceClass 9CBSE

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 Living in a large and well furnished house

Soln: Answer is (d) Living in a large and well furnished house

ScienceClass 9CBSE

Which disease is not transmitted by mosquitoes? (a) Dengue (b) Malaria (c) Brain fever or encephalitis Pneumonia

Soln: Answer is (d) Pneumonia Explanation: Pneumonia is transmitted through air not mosquitos.

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