Selina ICSE Class 8 Biology Solutions Chapter 8 Diseases and First Aid

Selina ICSE Solutions

Question 1. Put a tick mark (✓) against the correct alternative in the following statements:

(a) A mosquito is a vector for
a. Typhoid
b. Cholera
c. Malaria
d. Jaundice
Solution: (c) Malaria

(b) Dengue is caused by a
a. Protozoan
b. Virus
c. Worm
d. Fungus
Solution: (b) Virus

(c) The idea of vaccination was conceived by
a. Charles Darwin
b. Alexander Flemming
c. Issac Newton
d. Edward Jenner
Solution: (d) Edward Jenner

(d) Which one of the following is not a psychotropic drug?
a. Morphine
b. Cocaine
c. Heroin
d. Penicillin
Solution: (a) Morphine

(e) Which one of the following is a communicable disease?
a. Measles
b. Cancer
c. Heart stroke
d. Allergy
Solution: (c) Heart stroke

(f) Cataract is a disease of: –
a. Ears
b. Nose
c. Eyes
d. Throat
Solution: (c) Eyes

(g) Infectious diseases can be prevented by:
a. Medicines
b. Proper food
c. Immunisation
d. Exercise
Solution: (d) Exercise

(h) Which one of the following is a genetic disease?
a. Scurvy
b. Leukemia
c. Goitre
d. Haemophilia
Solution: (c) Goitre

(i) Which one of the following is a degenerative disease?
a. Thalassemia
b. Beri-beri
c. Cataract
d. Diabetes
Solution: (a) Thalassemia

(j) Pellagra is one disease caused by the deficiency of:
a. Vitamin B3
b. Vitamin B1
c. Vitamin C
d. Vitamin D
Solution: (d) Vitamin D

(k) Hay fever and asthma are
a. Deficiency diseases
b. Genetic diseases
c. Organic diseases
d. Allergy diseases
Solution: (c) Organic diseases

Short Answer Questions:

Question 1. What is a non-communicable disease?
Diseases like diabetes and heart attacks that are brought on by the body’s organs not functioning properly. They are not contagious and are not brought on by microorganisms.

Question 2. What are communicable diseases?
Communicable diseases are those that transmit from one person to another by the entrance of germs.

Question 3. How can we control spreading of diseases by mosquitoes and houseflies?
We can control spreading of diseases by mosquitoes and houseflies by using repellants, throwing garbage in covered bins, avoiding stagnation of water and checking breeding of these insects.

Question 4. Public hygiene is equally important as personal hygiene. Give reasons.
Personal hygiene refers to keeping oneself clean. However, maintaining good public hygiene is equally crucial because an unclean environment can increase the number of mosquitoes, houseflies, and other insects that are primary carriers of numerous communicable diseases. Having a clean environment is beneficial for our mental health since it calms our minds.

Question 5. What is a deficiency disease?
These diseases are caused by lack of nutrients, vitamins, minerals as a anaemia, goitre.

Question 6. Biting nails should be strictly avoided. Give reason.
As the soil contains various microorganisms that cause diseases, nail biting may result in numerous illnesses. To prevent diseases, nails should occasionally be trimmed.

Question 7. Regular exercise and proper rest is a must. Give reason.
Regular exercise keeps our body strong and immune to many diseases, rest refreshes our body.

Question 8. Children eating more of fast food tend to suffer from obesity (overweight). Comment
Fast food contains a lot of carbohydrates and lipids, such pizza, burgers, patties, fatty dishes, etc. Children who eat these quickly gain weight and become more obese since they do not engage in a lot of physical activity.

Question 2. Name the following:
1. A viral disease caused due to unhealthy sexual contact
2. A disease caused due to Plasmodium
3. A disease caused by the bite of female Anopheles mosquito
4. Two viral diseases caused by mosquito bites
5. Any droplet — borne disease
6. A viral disease caused by the bite of a dog
7. A disease due to choking of coronary artery
8. Two diseases caused due to deficiency of protein in the diet of a child.
2. Malaria
3. Malaria
4. Dengu, Chikungunya
5. Amoebiasis, Cholera, Hepatitis A.
6. Rabies/Hydrophobia
7. Atheraosclerosis
8. Kwashiorkor and marasmus

Question 3. Write short (2-3 sentences) notes on the following:
1. Disease
2. Immunisation
3. Pathogen
5. Vaccination
6. Vector
1. Disease:- Disease is a deviation from normal health brought on by a structural or functional body condition. Disease can result from food deficiencies, organ malfunction, genetic abnormalities, inappropriate metabolism, allergies, cancer, and mental illnesses such diabetes, haemophilia, leukaemia, and schizophrenia.
2. Immunization:- This is the process of making the body resistant to particular diseases by introducing the corresponding, weaker pathogens. Thus, through immunization, we gain resistance to the relevant disease. Vaccines are substances or germs that are injected into the body to increase resistance to the disease in question. The person’s body generates antibodies as a result, and these antibodies may be able to save the person. The shot can be administered by the Typhoid vaccine and BCG vaccines are both available.
3. Pathogens:- The microorganisms that infect humans and other animals and Pathogens are defined as plants. They contaminate people with the diseases or either through the air or the items worn by those who are ill. Pathogens could various bacterial, viral, fungal, protozoan, or worm species.
4. AICD:- Acquired immune deficiency syndrome, or AIDs It is a viral illness brought on by the HIV-related virus (Human immuno deficiency virus) This virus weakens the immune system. The human body’s mechanisms are incredibly fragile. The body’s immune system functions as W.B.C. gets weaker. As a result, the person contracts infectious diseases quite quickly. This Sexual activity can spread disease since one partner may be a carrier disease.
5. Vaccination:- The illness is extremely lethal. By injecting a deceased or weakened disease-causing bacterium into a body to promote the development of antibodies and create immunity to that disease-causing organism, vaccination is a technique for immunizing the body against a specific disease.
6. Vector:- A vector is an organism that spreads diseases, or disease-causing microorganisms, from one host to another. They are the ones that spread the sickness. For instance, a mosquito or houses fly.

Long Answer Questions:

Question 1. What is vaccination? Mention the four ways in which vaccine’s are prepared, giving the name of one disease for which each type of vaccine is used.
To build up the body’s defenses against a certain disease, we inject germs or germ-containing substances into the body. Prophylaxis is the term for the procedure while vaccination refers to the substance administered to the body. The germ or the germ material is injected into the body as part of the TAB vaccine or given orally as polio drops. The term “vaccine” or “vaccination” was once associated with the small pox, although it is now used more broadly. Preparation:
1. The body is exposed to dead germs. These serve as typhoid, TAB, and Salk’s vaccines for poliomyelitis vaccines. Dogs bite rabies vaccination.
2. Living weakened germs: The living germs are given a treatment that renders them exceedingly vulnerable.
3. Living, fully pathogenic germs that are administered to the body in modest quantities as a vaccination and which stimulate the body to create antibodies that prevent a certain type of germ from causing a disease: This vaccine involves injecting the patient with the cowpox virus. It resembles the small pox virus a lot.
4. Toxoids: Toxoids are made from the extracts of the poisons that bacteria release. The addition of formalin into these toxins, which are poisons, renders them harmless them. They maintain their functionality, so when they are ingested into the body. They create antibodies that are absorbed by the body and prevent the growth of pathogens.

Question 2. Burns can be superficial burns, deep burns or chemical burns. What emergency care you would suggest in each case.
When someone accidentally gets burned, they should not cut the blisters or remove clothing from the burned region. Applying butter, Vaseline, or ointment is advised.
• Superficial burns: Apply some oily substance, such as bumol, castor oil, Vaseline, butter, etc. after washing off any superficial burns with cold water.
• Deep burns: Avoid applying cold water to damaged areas when they are deep. Visit a hospital for assistance and remain under the care of a skin specialist doctor.
• Chemical burns: Cover chemical burns, such as those caused by acid or other chemicals, with dressing after washing with running water for 10 minutes.

Question 3. Describe the ways in which communicable diseases are transmitted through various indirect methods.
Indirect routes of infectious disease transmission:
1. Using objects that have been used by infected people: Healthy individuals can contract an infectious disease by handling goods like towels, handkerchiefs, cutlery, and bedding that have been used by patients with communicable diseases. This approach is used to spread diseases like tuberculosis, ringworm, the common cold, and influenza.
2. Contaminated food and water: Dysentery and cholera are two diseases that spread by contaminated food and water. If consumed by a healthy person, flies sitting on the meal may have bacteria that could make them throw up and have loose bowel movements. Similarly, entamoeba-infected water and food can make people sick with dysentery if they consume it.
3. Vectors or carriers: Mosquitoes, house flies, ticks, and other insects spread germs from the point of infection to healthy people, causing them to contract diseases including malaria, cholera, and plague. These creatures are known as vectors since they do not actually have the illness. Mosquitoes feed on human blood and spread disease-causing protozoans from sick people to healthy ones. In a similar way, houseflies transfer bacteria from sewage and rubbish to food. If the people consume this food, they risk contracting typhoid and other illnesses.
4. Air: A person with a cold may blow out billions of germs that are transported by the air and could infect a healthy person. TB spreads from one person to another.

Question 4. Given a crossword puzzle. Read the clues across and clues downward, and fill up the blank squares. Check up your performance with the correct solution given at the end. Clues
1. Category of pathogen that causes diseases, like common cold and mumps.
2. These may readily grow in your hair, if you do not wash it regularly.
3. This is the vaccine for preventing tuberculosis.
4. Cover this part of your body by a handkerchief while sneezing to prevent droplet infection to others.
5. The disease pertussis is popularly known as whooping
6. One of the most common insects which visit our exposed foods and contaminate them.
7. A disease that weakens body’s defence system.

8. Germ or germ – substance introduced into the body to prevent occurrence of an
infectious disease.
9. A disease in which the eyes, the skin and the urine turn yellow.
10. An organ usually affected by tuberculosis.
11. A disease caused by the bite of an infected dog, and which affects the central nervous system.

Selina ICSE Class 8 Biology Solutions Chapter 8 Diseases and First Aid


Selina ICSE Class 8 Biology Solutions Chapter 8 Diseases and First Aid

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