Selina Solutions for Class 9 Biology Chapter 17 - AIDS to Health

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1. Give one example of each of the following:
   1. Germ killing body secretion.
   2. Germ trapping body secretion
   3. Mechanical barrier that prevents the entry of germs into the body.

   Solution:

   1. Germ killing body secretion – saliva
   2. Germ trapping body secretion – Sebum
   3. Mechanical barrier that prevents the entry of germs into the body – Mucus
2. Mention of the following statements are True(T) or false(F)
   1. Immune system deals with the germs after they have entered the body.
   2. Antibodies eat up the germs
   3. Human beings can suffer from all those diseases which attack dogs
   4. Anti-venin injection against snake bite is an example of artificially acquired passive immunity.
   5. Mother’s antibodies may reach the fetus through placenta
   6. A person having once suffered from measles usually gets repeated attacks.

   Solution:

   1. The statement is true.
   2. The statement is true.
   3. The statement is false. Human beings are immune to a highly infectious disease of Dogs.
   4. The statement is true.
   5. The statement is true.
   6. The statement is false. A person having once suffered from measles will not normally suffer from it again.
3. Define the term prophylaxis.Solution:

   Artificially introducing the germs or the germ substance into the body for developing resistance to a particular disease. Scientifically this process is referred to as prophylaxis.

4. Name the four categories of materials used for preparing vaccinesSolution:

   The four categories of vaccines are:

   • Killed germs
   • Living weakened germs
   • Living fully poisonous germs
   • Toxoids
5. Name the diseases prevented by:
   1. Salk’s vaccine
   2. BCG vaccine
   3. DTP vaccine

   Solution:

   1. Salk’s vaccine – Poliomyelitis
   2. BCG vaccine – Tuberculosis
   3. DTP vaccine – Pertussis(whooping cough), diphtheria, tetanus
6. Correct the following statements if they are false (without changing the first word).
   1. DDT is an antiseptic.
   2. Penicillin is a disinfectant.
   3. Disinfectants are applied on the body
   4. Deodorants are both antiseptic as well as disinfectants
   5. Alexander Fleming discovered the first sulphonamide
   6. Antibiotics cannot be made synthetically
   7. Sulphonamides are now rarely used.

   Solution:

   1. DDT is a disinfectant.
   2. Penicillin is an antibiotic.
   3. Disinfectants cannot be applied to the body.
   4. Deodorants are neither antiseptics nor disinfectants.
   5. Alexander Fleming discovered the first antibiotic
   6. Antibiotics can be made synthetically.
   7. Sulphonamides are now rarely used.
7. List any three uses of antibiotics.Solution:

   The three uses of antibiotics are:

   • They are used to fight infections
   • Certain antibiotics are used as food preservatives, especially fresh meat and fish.
   • Some are used to control plant pathogens

Multiple Choice Type

(Select the most appropriate option in each case)

1. Penicillin is
   1. An antiseptic
   2. A disinfectant
   3. An antibiotic
   4. An anti-toxin

   Solution:

   (c) An antibiotic

   It was the first antibiotic discovered by Alexander Fleming.

2. “T” in DTP vaccination stands for
   1. Tuberculosis
   2. Typhoid
   3. Tetanus
   4. Tonsillitis

   Solution:

   (c) Tetanus

   DTP stands for Diphtheria, Tetanus and Pertussis

3. World Healthy Day is celebrated on
   1. April 7
   2. February 21
   3. October 10
   4. January 15

   Solution:

   (a) April 7

   It is celebrated to create consciousness about keeping oneself healthy and to disseminate the message at all levels.

4. DTP stands for
   1. Diphtheria, Polio and Tetanus
   2. Diphtheria, Pertussis and Tetanus
   3. Dysentery, Polio and Typhoid
   4. Diphtheria, Polio and Typhoid

   Solution:

   (b) Diphtheria, Pertussis and Tetanus

   DTP it is a vaccination used the treat Pertussis, Diphtheria and Tetanus

5. Vaccines are:
   1. An extract of toxins secreted by bacteria
   2. An extract of dead and weakened microbes
   3. Strong chemicals obtained from fungi
   4. Chemicals that are applied to the skin to kill bacteria.

   Solution:

   (b)An extract of dead and weakened microbes

   The material introduced into the body during the practice of prophylaxis is known as the vaccine

Very short answer type

1. Name the following:
   1. The drug based on arsenic compound, produced in 1910 which killed germs of syphilis.
   2. The antibiotic that was discovered first.
   3. The category of immunity required in the treatment of snake-bite.
   4. Any four antiseptics, any two disinfectants and any two antibiotics.
   5. The vaccines that help to produce immunity against Polio.

   Solution:

   1. The drug based on arsenic compound, produced in 1910 which killed germs of syphilis – Salvarsan and Arsphenamine
   2. The antibiotic that was discovered first – Penicillin
   3. The category of immunity required in the treatment of snake-bite – Passive acquired immunity
   4. Any four antiseptics, any two disinfectants and any two antibiotics.
      

      Antiseptics	Carbolic acid, Lysol, Boric acid, Iodine
      Disinfectants	Cresol, phenol
      Antibiotics	Penicillin, Ampicillin

   5. The vaccines that help to produce immunity against Polio – OPV – Oral polio vaccine
2. Write the full forms of:
   1. AIDS
   2. BCG
   3. DPT vaccine
   4. WHO
   5. HIV
   6. ATS
   7. TAB
   8. STD

   Solution:

   1. AIDS – Acquired Immuno Deficiency Syndrome
   2. BCG – Bacillus Calmette Guerin
   3. DPT vaccine – Diphtheria Pertussis and Tetanus vaccine
   4. WHO – World Health Organization
   5. HIV – Human Immunodeficiency virus
   6. ATS – Anti Tetanus Serum
   7. TAB – Typhoid Paratyphoid A & B
   8. STD – Sexually Transmitted Disease
3. Give the technical term for the kind of proteins produced in the blood to fight and destroy harmful microbesSolution:

   Antibodies. They are the immunoglobulins that are produced in the blood to fight and destroy harmful microbes.

Short Answer Type

1. Mention if the following statements are true (T) or false (F).
   1. Lysol is an antibiotic.
   2. Sweat and tears contain germs-killing substances.
   3. Our body can make only a limited variety of different antibodies
   4. Salk vaccine is used against tuberculosis
   5. Treatment by the use of chemicals is known as allopathy
   6. Alexander Fleming coined the term “antibiotic” for substances like penicillin.
   7. DDT is a disinfectant.
   8. Vaccine provides the body with Active Immunity
   9. Penicillin was discovered by Alexander Fleming.
   10. BCG is the vaccine given to babies to help build immunity against three common diseases.

   Solution:

   1. The statement is false. Lysol is an antiseptic
   2. The statement is true.
   3. The statement is false. Our body can make an unlimited variety of different antibodies
   4. The statement is false. Salk vaccine is used against Poliomyelitis.
   5. The statement is false. Use of chemicals to treat is known as chemotherapy
   6. The statement is false. The term was coined by Selman Waksman.
   7. The statement is true.
   8. The statement is false. It provides the body with Passive Immunity.
   9. The statement is true.
   10. The statement is false. BCG is used to treat Tuberculosis.
2. Differentiate between:
   1. Antiseptic and antibiotic
   2. Antiseptic and disinfectant
   3. Disinfectant and deodorant
   4. Vaccination and sterilization
   5. Active Immunity and passive immunity
   6. Innate immunity and acquired immunity

   Solution:

   The differences are as follows:

   a)Antiseptic and antibiotic

   Antiseptic	Antibiotic
   It is a mild chemical substance applied to the body to kill germs	It is a chemical substance produced by the microbes which kill or hinders the growth of microbes.

   b) Antiseptic and disinfectant

   Antiseptic	Disinfectant
   It is a mild chemical substance applied to the body to kill germs	It is a strong chemical applied to spots on the body where germs live and multiply

   c) Disinfectant and deodorant

   Disinfectant	Deodorant
   It is a strong chemical applied to spots on the body where germs live and multiply	They are neither antiseptics nor disinfectants. They are used to mask the bad smell and are aerosols.

   d) Vaccination and sterilization

   Vaccination	Sterilization
   It is the introduction of any kind of weakened/dead germs into the body of a living beings to develop resistance against diseases.	Process of elimination of microbes from a surface contained in a fluid, in a compound such as biological culture media or in medication

   e) Active Immunity and passive immunity

   Active Immunity	Passive immunity
   Developed by an individual due to a previous infection or antigen which naturally enters the body	The immunity provided to an individual from an outside source as readymade antibodies.

   f) Innate immunity and acquired immunity

   Innate Immunity	Acquired Immunity
   It is the immunity by virtue of genetic constitutional makeup	It is the resistance to a disease the body acquires in his lifetime.

3. Name any three vaccines and the diseases for which they provide immunity. Solution:

   Three vaccines and the diseases for which they provide immunity are as follows:

   Name of the Vaccine	Disease for which immunity provided
   TAB	Typhoid
   Salk’s vaccine	Poliomyelitis
   BCG	Tuberculosis

4. Given below is a table of certain vaccines, the diseases against which they are used and the nature of the vaccine. Fill up the gaps 1 – 10.
   

   Vaccine	Disease(s)	The nature of vaccine
   TAB	__________	__________
   Salk’s vaccine	__________	__________
   BCG	__________	Living weakened germs
   Vaccine for measles	Measles	__________
   Cowpox virus	__________	__________
   Toxoids	__________	Extracts of toxins
   		Secreted by bacteria

   Solution:

   Vaccine	Disease(s)	The nature of vaccine
   TAB	Typhoid	Killed germs
   Salk’s vaccine	Poliomyelitis	Killed germs
   BCG	Tuberculosis	Living weakened germs
   Vaccine for measles	Measles	Living weakened germs
   Cowpox virus	Small pox	Living fully poisonous germs
   Toxoids	Diphtheria	Extracts of toxins
   	Tetanus	Secreted by bacteria

5. Given below are the groups of certain substances of particular categories. Mention the category of each group and identify the wrong example giving a reason.
   1. Lysol, benzoic acid, DDT, mercurochrome.
   2. Formalin, Iodine, Lysol, Phenol
   3. BCG, DTP, ATP.
   4. Tears, Skin, Nasal Secretion, HCl (in stomach)

   Solution:

   1. Lysol, benzoic acid, DDT, mercurochrome – DDT is a wrong example as all others are antiseptics and DDT is a disinfectant which cannot be applied on the skin.
   2. Formalin, Iodine, Lysol, Phenol – Iodine is a wrong example as all others are disinfectant where Iodine is an antiseptic
   3. BCG, DTP, ATP – ATP is a wrong example as all others are vaccines whereas ATP carries energy in living cells.
   4. Tears, Skin, Nasal Secretion, HCl (in the stomach) – skin is a wrong example as all others are germ-killing secretions whereas skin is a protect mechanical barrier, preventing germ-entry.
6. Given below is a scheme of classifying immunity against human diseases. Fill up the types of immunity in the blanks 1-9.

   Solution:

   1 – Innate Immunity

   2 – Acquired Immunity

   3 – Specific Immunity

   4 – Active acquired Immunity

   5 – Passive acquired Immunity

   6 – Natural acquired active Immunity

   7 – Artificial acquired active Immunity

   8 – Natural acquired passive Immunity

   9 – Artificial acquired passive Immunity

7. List any four ways in which the antibiotics are being used.Solution:

   Listed below are the four applications of antibiotics:

   • They are widely used to fight infections
   • They are used as food preservatives especially in fish and fresh meat
   • Used in treating animal feed to prevent internal infections
   • Used for controlling plant pathogens
8. List the merits of local defence system. Solution:

   Merits of the local defence system are as follows:

   • They instantaneously start working
   • They are not dependent on previous exposure to infections
   • Are effective against a wide range of potentially infectious agents.
9. Suppose a person develops the disease diphtheria. Comment upon the principle of the treatment he should receive. Solution:

   Diphtheria is a bacterial disease and is infectious. It causes cold, cough, sneeze, if left untreated in severe cases, it may lead to paralysis or heart failure.

   Treatment for Diphtheria:

   • Combination of supportive care and medication
   • Prompt intravenous administration of diphtheria toxoid which is made harmless
   • Once this is administered into the body of the patient, it stimulates antibody production against pathogens that cause diphtheria

Long Answer Type

1. The principle of vaccination is to produce immunity against a disease. Explain. Solution:

   Vaccination is artificially introducing germs or its substances in the body in order to develop resistance to a particular disease. This practice, scientifically referred to as prophylaxis and the material being introduced is the vaccine. Vaccines are generally introduced by injection or orally sometimes.

   Once the vaccine enters the body, it triggers the lymphocytes to synthesize antibodies to fight germs for that specific disease. Vaccines provide our immunity with a signal to synthesize particular antibodies therefore the principle of vaccination is to provide immunity against a disease.

2. “Abnormally, large number of WBC’s in the blood are usually an indication of some infection in our body”. Comment on the statement.Solution:

   Whenever there is an infection in the body, the immune system receives a signal to synthesize particular antibodies. In response to the quantity of germ-multiplication in the body, white blood cells multiply rapidly which enables it to produce more antibodies thereby stopping in an infection on time. Consequently, abnormal numbers of WBCs are an indication of some infection in the body.

3. Explain briefly, the role of the following health aids:
   1. Antiseptics
   2. Disinfectants
   3. Vaccines

   a)Antiseptics –

   It is a mild chemical substance applied to the body to prevent its growth and kill germs.

   Example – Iodine and Lysol

   b)Disinfectant

   These are the chemicals that kill microbes once they come in contact with them, they are too strong to be used on the body.

   Example – Phenol and Cresol

   c)Vaccines –

   They are the substances that are administered in the body to provide passive immunity. These are the materials that are germs or secreted by germs.

   Example – DTP, OPV

Selina Solutions for class 9 Biology Chapter 17 – AIDS to Health

ICSE Class 9 Biology Chapter 17 – AIDS to health chapter is classified under Unit – VI of Biology textbook – Health & Hygiene. Health refers to the normal and healthy state of the body in all the three aspects namely – physical, mental and social wellness while Hygiene concerns with the conditions and practices in order to maintain health and prevent any chance of diseases.

The unit AIDS to health is included in the syllabus for class 9 in order for students to familiarise with various (natural and artificial) ways to protect oneself from diseases. Apart from the importance of the topic for examination, the information provided is very essential and required to lead a healthy life.

Concept of health is discussed at the personal and community level. Immunity is the body’s defence against diseases. The concept is discussed along with the way in which the disease can enter the body. Some other concepts that are discussed are:

• Local defence system
• Immune system
• Types of immunity
• Antibodies
• Vaccination and immunization

The chapter covers the following types of questions:

• Multiple-choice questions
• State whether true/false
• Fill ups
• Very short answer type questions
• Short answer type questions
• Long answer type questions

List of subtopics covered in Chapter 17 – AIDS to Health

List of Exercise

Selina Solutions for class 9 Biology Chapter 17 – AIDS to Health

Health is an important aspect of life that is often ignored. Through this chapter, students are enlightened with the basic concept of immunity. It is the basic defence system of the body that counter attacks if there is an entrance of any foreign particle in the body. The defence system of the body works at two levels:

• Local defence system
• Immune system

The immune system provides resistance to the onset of disease after infection by harmful germs. There are different types of immunity, and further sub-categories under each of these:

• Innate immunity
• Acquired immunity

Through this chapter, the readers are also guided about the concepts of antibiotics, antiseptics, disinfectants and their sources and the various ways through which diseases can be treated and prevented by the use of these.

Key Features of Selina Solutions for class 9 Biology Chapter 17 – AIDS to Health

• Easy to understand and helpful study tool
• Detailed and step by step organization of answers
• Solutions are answered using the simplest language and easy terminologies
• Selina solutions are easily accessible
• Explanation provided for the activity – State whether statements are true or false
• Use of pointers wherever necessary