ICSE Class 9 Biology Solutions Chapter 16 Diseases: Cause and Control

Class 9th ICSE Biology Solutions Chapter 16 Diseases: Cause and Control

Question 1.
Match the diseases in column I with their categories in column II :

Column I	Column II
Plague	a) Sporadic
Malaria	b) Pandemic
Goitre	c) Epidemic
AIDS	d) Endemic

Answer:

Column I	Column II
Plague	a) Sporadic
Malaria	b) Pandemic
Goitre	c) Epidemic
AIDS	d) Endemic

Question 2.
Classify the following diseases into communicable and non-communicable diseases: cholera, beri-beri, colour blindness, diabetes, malaria, plague, heart-attack.
(i) Communicable ……………..
(ii) Non-communicable …………………..
Answer:
(i) Communicable-malaria, plague, cholera.
(ii) Non-communicable-beri-beri, colour blindness, diabetes, heart-attack.

Review Questions

A. Multiple Choice Type

Question 1.
A disease widely spread worldwide is known as :
(a) endemic
(b) epidemic
(c) pandemic
(d) sporadic
Answer:
(c) pandemic

Question 2.
The letter “B” in the name B.C.G vaccination stands for:
(a) Brief
(b) Beri-beri
(c) Bacteria
(d) Bacillus
Answer:
(d) Bacillus

Question 3.
Use of disposable syringes for injecting medicines, etc. is specially advised to prevent
(a) Poliomyelities
(b) Mumps
(c) Rabies
(d) AIDS
Answer:
(d) AIDS

Question 4.
The vector that transmits the malarial pathogen is :
(a) Culex mosquito
(b) Housefly
(c) Anopheles mosquito
(d) Entamoeba
Answer:
(c) Anopheles mosquito

Question 5.
Amoebiasis is caused by the protozoan :
(a) Amoeba proteus
(b) Engelena
(c) Plasmodium
(d) Entamoeba
Answer:
(d) Entamoeba

Question 6.
BCG vaccine provides immunity against :
(a) Tetanus
(b) Cholera
(c) AIDS
(d) Tuberculosis
Answer:
(d) Tuberculosis

Question 7.
The expanded form of AIDS of :
(a) Active Immunity Deficiency Syndrome.
(b) Acquired Immuno Deficiency Syndrome.
(c) Acquired Immuno Deficiency Status.
(d) Active Immuno Deficiency Syndrome.
Answer:
(b) Acquired Immuno Deficiency Syndrome.

B. Very Short Answer Type

Question 1.
Mention whether following statements are True (T) or False (F):
(a) Filiariasis is transmitted by the housefly. T/F
(b) Malaria is caused by a protozoan. T/F
(c) BCG vaccine is used for the chicken pox. T/F
(d) Louis Pasteur discovered a cure for malaria. T/F
(e) AIDS is caused by a bacterium. T/F
(f) HIV is a serious disease, usually fatal. T/F
(g) AIDS is not transmitted by contact with patient’s clothes.
(h) Chicken pox and hepatitis are bacterial diseases. T/F
(i) Goitre is endemic in sub-Himalayan regions of India. T/F
(j) AIDS is caused by a fungus. T/F
(k) Hay fever and asthma are allergies.T/F
(l) Smallpox still occurs in India. TIF
(m) The disease fihiariasis is caused by the bite of the female nopheles mosquito. TIF
Answer:
(a) F
(b) T
(c) F
(d) F
(e) F
(f) F
(h) T
(i) T
(j) F

Question 2.
Write the full form of AIDS.
Answer:
Acquired Immune Deficiency Syndrome.

Question 3.
Name the following :
(a) Category of pathogen that causes diesases, like common cold and mumps ……………………
(b) The vaccine for preventing tuberculosis ……………………
(c) An organ usually affected by tuberculosis ……………………
(d) A disease that weakens body’s defense system against infections ……………………
(e) Germ of germ-substance introduced into the body to prevent occurrence of an infectious disease ……………………
(f) The vector responsible for transmission of sleeping sickness ……………………
(g) The microorganism that requires a host to produce ……………………
(h) The popular name of the disease filiariasis ……………………
Answer:
(a) viruses,
(b) BCG,
(c) lungs,
(d) AIDS,
(e) antigen,
(f) Trypanosoma brucei,
(g) parasites,
(h) elephantiasis.

C. Short Answer Type

Question 1.
Define the terms infection, pathogen, incubation period and allergen.
Answer:
(a) Infection-Transmission of disease from one person to another is called infection.
(b) Pathogen- Cause of disease is called pathogen.
(c) Incubation period- An infectious disease, usually does not appear immediately after the infection, but it may take some time varying from a few hours to a few days.
(d) Allergen=-Any substance that causes allergy.

Question 2.
What are the different ways in which infectious diseases can spread?
Answer:
Different ways in which infectious diseases can spread are-
(i) Through contact.
(ii) Through various agents like-bacteria, viruses etc.
(iii) Air.
(iv) Sexual intercourse.
(v) Infected usage of things like-needles etc.
(vi) Unhygienic environment.

Question 3.
Name any four non-infectious diseases and their causes.
Answer:
Non-infectious diseases are-

Disease	Cause
1. Diabetes 2. Colour blindness 3. Beri-Beri 4. Coronary Thrombosis (heart-disease)is stopped	Lack of insulin Genetic Vitamin-B deficiency Blood supply to heart

Question 4.
Why is it important to know how the germs leave the body of a patient?
Answer:
It is important to know how germs leave the body of a patient so as to successfully treat the person suffering from the disease and also to find immunization for the respective disease caused by germs.

Question 5.
Name the causative germ of AIDS. How is this disease transmitted?
Answer:
Causative Germ-Human immune deficiency virus Transmission of AIDS

1. Sexual contact.
2. Contaminated blood transfusion.
3. Mother to child transmission during pregnancy
4. Shared injection needles.

D. Long Answer Type

Question 1.
Write very briefly about the following:
(a) B.C.G
(b) Incubation period
(c) Chicken pox
(d) Hepatitis A
Answer:
(a) B.C.G -Vaccination found useful in developing immunity for tuberculosis.

(b) Incubation period -Discussed in answer 1 (c) of this lesson.

(c) Chicken pox -The disease is cause by Herpes virus ‘Varicella Zoster’. It is a common contagious disease occurring mainly in children, but can also affect adults. The disease spreads quickly by close contact with an infected person. Its symptoms are highly irritating rashes that appear on the body starting near the chest and back and gradually spread to arms, legs, face and head. The rashes first appear as a pink spot and rapidly changes to a watery blister, The blister gradually shrivels up and soon dries forming scabs, this time is the infectious period.

(d) Hepatitis A – Hepatitis A virus has an incubation period of 14 to 45 days and is most common in children and young adults, mainly transmitted by contaminated food and water.

Question 2.
What are the causes and symptoms of malaria, chicken pox and tuberculosis? How can theese diseases be prevented?
Answer:
(a) Malaria :
Causes
Malaria caused by a protozoan through the bite of mosquito. ,
Symptoms
Chilling, shivering, high fever accompanied with headaches and nausea, fever subsides with profuse sweating.

Prevention :

• Keeping insects aways.
• Use Anti-malarial drugs like chloroquine, primaquine.
• Using mosquito nets or repellants.

(b) Chicken Pox :
Causes:
The disease is caused by a Herpes virus ‘Varicella Zoster’. Symptoms Dark red coloured rash or pox changing into vesicles, crusts and falling.

Prevention:

• Do not prick the blister.
• Keeping the rashes clean and dry.
•  Use of neem leaves too helps.

(c) Tuberculosis :
Disease of the lungs caused by a small rod-shaped bacterium (Mycobacterium tuberculosis) and spread by sputum from infected persons.
Prevention : B.C.G vaccination

E. Structured / Application / Skill Type

Question 1.
Given alongside is the diagram of an animal closely related with certain human diseases.
(a) Name the animal.
(b) Name the phylum and the class to which it belongs.
(c) Name any two diseases which it spreads.
(d) Can you call it a germ, a pathogen, a parasite or a carrier? Give reasons.
(e) Where does it breed?

Answer:
(a) House Fly
(b) Musca Nebula
(c) Cholera, Typhoid.
(d) Pathogen because housefly feeds on organic food like, rotting meat
(e) The housefly breeds in decaying organic matter including human and animal excreta.

Additional Questions

A. Tick the most appropriate Answer.

Question 1.
Communicable diseases are caused by
a. only viruses
b. only bacteria
c. only protozoa
d. viruses, bacteria protozoa and fungi
Answer:
d. viruses, bacteria, protozoa and fungi

Question 2.
Which of these is not a viral disease?
a. conjunctivitis
b. measles
c. tuberculosis
d. polio
Answer:
c. tuberculosis

Question 3.
Which of these is a not fungal disease?
a. ringworm
b. mumps
c. hepatitis
d. rabies
Answer:
a. ringworm

Question 4.
Typhoid spreads through
a. air
b. insect bite
c. canned food
d. polluted water
Answer:
d. polluted water

Question 5.
Botulism is a kind of
a. heart disease
b. food poisoning
c. delicious food
d. protozoa
Answer:
b. food poisoning

Question 6.
Ringworm is a disease of
a. heart
b. kidney
c. skin
d. lungs
Answer:
c. skin

Question 7.
Which of these diseases is spread through contact with infected rats?
a. dengue
b. sleeping
c. filariasis
d. plague
Answer:
d. plague

Question 8.
Protein deficiency leads to
a. marasmus
b. plague
c. anaemia
d. scurvy
Answer:
a. marasmus

Question 9.
Deficiency of vitamin K can lead to
a. blocked arteries
b. bleeding gums
c. haemorrhaged
d. rickets
Answer:
c. haemorrhage

Question 10.
Lack of insulin leads to Cause
a. atherosclerosis
b. diabetes
c. arthritis
d. goitre
Answer:
b. diabetes

B. Match the name of disease with its cause.

Disease	Cause
1. anaemia	a. deficiency of vitamin A
2. night blindness	b. deficiency of vitamin B
3. rickets	c. deficiency of iodine
4. beri-beri	d. deficiency of vitamin C
5. scurvy	f. deficiency of vitamin D
6. goitre	e. deficiency of iron

Answer:

Disease	Cause
1. anaemia	c. deficiency of iron
2. night blindness	a. deficiency of vitamin A
3. rickets	f. deficiency of vitamin D
4. beri-beri	b. deficiency of vitamin B
5. scurvy	d. deficiency of vitamin C
6. goitre	e. deficiency of iodine

C. Find the odd one out. Give reason for your choice.

Question 1.
night blindness, scurvy, beri-beri, typhoid
Answer:
Night blindness, scurvy, beri-beri, typhoid is odd all other terms relates to vitamins deficiency. Typhoid is bacterial disease.

Question 2.
Typhoid, chickenpox, polio, measles
Answer:
Typhoid is the odd one is bacterial disease and all other disease are viral

Question 3.
weak bones and teeth, dehydration, lack of haemoglobin, night blindness
Answer:
dehydration is odd one as it is the loss of water from the body and the body becomes very weak. All other deficiency diseases

Question 4.
calcium, vitamin D, iron, magnesium
Answer:
Vitamin B is odd one as it is vitamin and all other are minerals

Question 5.
diabetes, goitre, arthritis, heart attack, cancer
Answer:
Diabetes is odd one as it pertains to sugar as it comes through the urine. All other relate to body parts.

Question 6.
malaria, plague, measles, dengue, yellow fever.
Answer:
Measles is odd one as it is a viral disease but measles, yellow fever and dengue are caused by different types of Mosquitoes.

D. Differentiate between the following :

Question 1.
Acquired and congenital diseases :
Answer:
It is difficult to classify diseases but we can divide the diseases into two categories :
A 1. Congenial disease These are certain diseases which are right from the birth. These are called congenital diseases as chromosomal diseases as diabetes, Night blindness.

2. Acquired diseases These diseases develop in organism after its birth.
These diseases can be divided into two main groups :

1. Communicable diseases
2. Non Communicable diseases

1.Communicable diseases These diseases are passed by infected person to another healthy person directly or indirectly. Communicable diseases are caused by germs which are micro organism, can only be seen under the microscope. These be divided into four categories:

1. Bacteria: These are found everywhere and cause disease like Typhoid, Tetanus, Cholera, Diphtheria, Tuberculosis, leprosy, Pneumonia, Whooping cough and food poisoning.

2. Viruses: These can be seen under the electron microscope and are between the living and non living organism. They only multiply when they are inside a cell. They cause diseases like Chickenpox, Measles, Polio, Rabies, Cold, Influenza, Mumps conjunctiva.

3. Fungi :
These are non green plants may be single (yeast) or many celled (Agarics). These cause food poisoning and skin diseases Ring worm.

4. Protozoa: These are single celled organism and cause diseases like Malaria, Sleeping sickness, Amoebic dysentery,

b. Non-communicable diseases: These diseases can not be passed from person to person directly or indirectly. These diseases are Nutritional deficiency

diseases, Vitamin deficiency diseases, Mineral deficiency diseases.

Question 2.
Communicable and non-communicable diseases :
Answer:
A. Communicable diseases:
These diseases are passed by infected person to another healthy person directly or indirectly. Communicable diseases are caused by germs which are microscopic organism, can only be seen under the microscope. These disease causing germs can be divided into four categories:

1. Bacteria: These are found everywhere and cause disease like Typhoid, Tetanus, Cholera, Diphtheria, Tuberculosis, leprosy, Pneumonia, Whooping cough and food poisoning.

2. Viruses: These can be seen under the electron microscope and are between the living and non living organism. They only multiply when they are inside a cell. They cause diseases like Chickenpox, Measles, Polio, Rabies, Cold, Influenza, Mumps, conjunctive.

3. Fungi: These are non green plants these may be single called (yeast) or many called (Agarics). These cause food poisoning and skin diseases like Ring worm.

4. Protozoa: These are single celled organism and cause diseases like Malaria, Sleeping sickness, Amoebic dysentery.

b. Non-communicable diseases :
These diseases can not be passed from person to person directly or lindirectly. These diseases are Nutritional deficiency diseases,

Vitamin deficiency diseases, Mineral deficiency diseases. Protein energy deficiency as Rickets, night blindness, goitre, anaemia.

Question 3.
Infectious and deficiency diseases :
Answer:
Infectious diseases: These diseases are passed on by the infectious organism to healthy organism either directly or indirectly. The diseases are called infections diseases. Micro organisms which cause these are called germs. These germs can be put into four categories.

1. Bacteria :

These are found every where and cause many diseases as Diphtheria, Typhoid, Tetanus, Cholera, Tuberculosis etc.

2. Viruses: These are micro organisms which can be seen under the electron microscope. These divide only in the living cells. They cause diseases like Measles, Polio, Rabies, Cold influenza, Mumps, conjunctiva.

3. Fungi: These are non green plants and cause many disease and spoil food. These cause skin diseases as ring worm.

4. Protozoa: These are single celled micro organisms and cause diseases amoebic, sleeping sickness.
Deficiency diseases: When a person takes diet which fulfills the requirement of the body. It is called balanced diet. But it lacks one or two nutrients from the diet. Then a specific nutrient is lacking from the diet. It is malnutrition, It may cause deficiency diseases.

Vitamin deficiency: Vitamins are required in small quantities daily for good health and Mopergrowth. If these are not provided in required quantities. The deficiency vitamin may cause a specific diseases in the body as see it from the following chart

Vitamin	Sources of the vitamin	Deficiency diseases
A	Yellow of fruits and vegetables as Mango, Papita, Carrot, Fish, Egg	Night blindness
B	Egg, Whole rice, Yeast.	Bery-Bery
B12	Fish, Meat, Yeast	Anaemia
C	Tomato, Potato, Citrus, Fruits, Green leafy vegetable	Scurvy (swollen teeth) gums and bleeding
D	Liver, Egg, Milk, Sunlight	Rickets
E	Wheat, Milk, Fish meat	Skin & Reproductive system is affected
K	Haemorrhage ( Bleeding )	Cabbage, Spinach, Soyabean

Mineral deficiency: Mineral are needed in small quantities for proper growth and development of bones and teeth. They are essential for the R.B.C.S. They are important for proper Circulatory and nervous systems. Deficiency of minerals may cause diseases as shown in the following chart.


Middle healthy child ; either side-rachitic children of the same age.

E. Given below are the names of a few diseases. Classify them according to microorganisms which cause them.
Answer:
Various groups
1. Bacteria: Botulism, typhoid, whooping cough, diphtheria, cholera, pneumonia.
2. Viruses: Rabies, mumps, chickenpox, conjunctivitis, influenza, cold.
3. Fungi: Food poisoning, ring worm.
4. Protozoa: Sleeping sickness (spread by the bite of fly). Amoebic dysentery, malaria (through plasmodium)
5. Vector borne diseases: Plague (through rod shaped of bacterium present in the fleas of rats) filariasis (through worms caused by Culex mosquito)

G. Answer these questions.

Question 1.
Name the various microorganisms which cause communicable diseases. Give two examples each of the diseases caused by these microorganisms?
Answer:
Communicable diseases : These are those disease which pass from infected person to a healthy person through contact either directly or indirectly. These diseases which cause infections to the organisms are called infectious disease. These communicable diseases are caused by the following microorganisms.

1. Bacteria These are microscopic organisms found every where and caused many diseases like diphtheria, cholera, whooping cough, tetanus, leprosy, food poisoning. Botulism is also a food poisoning. Bacteria gets entry into the canned foods and release toxic substances which are harmful to the nerves. Unboiled milk can also be source of bacterial infection. So pasteurized milk should be used.

2. Viruses These are very tiny organisms. These can only be under the electron microscope. These can only multiply when inside the cell. They can cause many diseases as chickenpox, rabies, polio, cold, influenza, measles, and conjunctivitis spread through contact.

3. Protozoa These are one celled organisms and cause many diseases as amoebic dysentery, malaria, sleeping sickness.

4. Fungi These are non-green organisms. They may be single called (Yeast) or multicellular as in Agarics, Fomes. They cause as well many skin diseases (Ring Worm) and food poisoning (Botulism).

ICSE Class 9 Biology Solutions